W4186: Variability, Adaptation and Management of Nematodes Impacting Crop Production and Trade

(Multistate Research Project)

Status: Inactive/Terminating

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SAES-422 Reports

Annual/Termination Reports:

[01/16/2019] [01/13/2020] [01/11/2021] [01/01/1970] [02/13/2023]

Date of Annual Report: 01/16/2019

Report Information

Annual Meeting Dates: 11/08/2018 - 11/09/2018
Period the Report Covers: 10/01/2017 - 09/30/2018

Participants

Cynthia Gleason, Saad Hafez, Russell Ingham, Isgouhi Kaloshian, Vince Klink, Kathy Lawrence, Haddish Melakeberhan, Amy Michaud, Tom Powers, Phil Roberts, Brent Sipes, Steve Thomas

Brief Summary of Minutes

Group conversation regarding accomplishments of previous year and future plans for project renewal.

Accomplishments

Objective 1:   Characterize genetic and biological variation in nematodes relevant to crop production and trade.  Rapid and accurate identification of nematodes for regulatory and management purposes continues to be a challenge. A LAMP (Loop mediated isothermal amplification) assay was developed for the rapid identification of Meloidogyne chitwoodi and M. fallax from infested soil samples. The LAMP assay exploits the genetic variation between root-knot nematode species. As a result, M. chitwoodi and M. fallax can be identified in an assay that is more sensitive than conventional PCRs and does not require expensive thermocyclers or imaging equipment. Because M. chitwoodi is an important potato pathogen in the Pacific Northwest, the LAMP assay will be useful for growers to determine if the nematode is present in their fields. Building off this work, the Gleason lab is beginning to develop assays to identify specific races of M. chitwoodi that differ in host range and distribution in Washington. Discovery and identification of Meloidogyne species has been conducted using cytochrome c oxidase I (COI) DNA barcoding. The ML tree of 322 specimens currently includes 21 described species and 6 unknown species. A notable feature is that COI does discriminate M. konaensis and M. incognita grahami within the tropical group. We have been exploring the mitochondrial ND5 gene for added taxonomic resolution within the tropical group. Only two root-knot nematode species have been identified in Alabama, M. incognita and M. javanica. We have continued to build the COI DNA barcoding datasets of major groups of plant and insect parasitic nematodes. Recent additions to the datasets have been made for Aphelenchoides, the Criconematoidea, Heterodera, Heterorhabditis, Meloidogyne, Pratylenchus, and Steinernema. For Heterodera, DNA barcoding evidence for the North American presence of alfalfa cyst nematode, Heterodera medicaginis was made. Additional cyst species have been added including Meloidodera from Texas, Punctodera from Nebraska, and the first report of Heterodera trifolii in New Mexico. For Aphelenchoides, the COI barcode dataset remains at 154 specimens. An unresolved question is: what exactly are the species boundaries of A. besseyi? There is still uncertainty about Brazilian A. besseyi reproducing on forage grasses. Among the 154 specimens are five described species on the Aphelenchoides tree and multiple groups of unknown species. In the Heterorhabditis/Steinernema group, native isolates of both Heterorhabditis and Steinernema were found during corn management trials targeting corn rootworm in central Nebraska. The addition of a number of reference isolates (named strains) from the USDA via David Shapiro-Ilan was made. These native isolates are being re-isolated to determine their physiological and biological characteristics. The annotated Criconematoidea dataset now includes 1,701 specimens. The Pratylenchus tree now consists of 860 specimens, not counting GenBank accessions. The tree represents 527 agricultural fields. This tree provides a comprehensive picture of Pratylenchus diversity in the Great Plains Region. Using the COI primer set JB3/5, we have amplified other taxa including: Malenchus, Lelenchus, Filenchus, Aphelenchus, Eudorylaimus, Acrobeloides, Cervidellus Acrobeles, Eucephalobus, Zeldia, Helicotylenchus, Hoplolaimus, Aorolaimus, Rotylenchus, Scutellonema, Scutylencus,Tylenchorhynchus, Rotylenchulus,  Longidorus, Xiphinema, and Aporcelaimellus. Several first reports of nematodes have been noted. Cactodera cacti was isolated from cactus in Idaho. This is a quarantine pest. The alfalfa cyst nematode, Heterodera medicaginis, was identified in Kansas and Montana. The project also noted the first report of Heterodera trifolii in New Mexico.  Objective 2:  Determine nematode adaptation processes to hosts, agro-ecosystems and environments.  The biological parameters used to measure nematodes can appear straightforward. However, environmental factors, slight modifications to protocols among laboratories, and differences among people can result in different measures of a biological parameter. A study was conducted to determine if Meloidogyne incognita reproductive factors (Rf) calculated from the differential-host test differ based upon what the host crop the nematode was surviving on in the field. Three large soil samples were taken from a root-knot nematode infested field in central Alabama. Each soil sample was collected from a different area in the field that had been cropped with cotton, soybean, or corn over the last three years. A differential-host test was then run on each of the samples for root-knot species and race identification and for host range and reproductive analysis. The Rf was calculated for each population on eight different crops. All three samples were identified as Meloidogyne incognita race 3 by the differential host tests, however, the Rf was always highest on the crop that was the original host of the population in all three samples. Meloidogyne incognita grown on cotton for three years had n Rf of 8.7 on cotton but the Rfs on corn and soybean were 1.7 and 2.2 respectively. The same trend was observed on soybean. Meloidogyne incognita grown on soybean for three years had an Rf of 6.6 on soybean but lower Rf’s on cotton and corn of 3.2 and 2.1, respectively. Corn supported the lowest Rf on corn (4.1) and an Rfs of 2.7 on cotton and 1.7 on soybean. Thus, crop rotation may reduce M. incognita race 3 population levels even though the rotation crop is a susceptible host.    Dissemination of nematode pests is important for management and a fundamental tactic of IPM is pest exclusion. Dissemination occurs in many ways and some methods have been ignored. Our data indicate that snails and slugs (terrestrial gastropods), common in agricultural production systems, are associated with at least 6 genera of plant-parasitic nematodes. Furthermore, snails may disseminate plant-parasitic nematodes through deposition of viable propagules in fecal pellets. Methods for exclusion may only be developed if means of pest dissemination are understood. At present, terrestrial gastropods have not been considered as a means of nematode dissemination in agricultural production systems.   Alleviating the intertwined and grand challenges of food and nutritional insecurities have been a major focus. Plant-parasitic nematodes (PPN) and poor soil health negatively affect crop yield. Farmers may have limited knowledge of the cause-and-effect relationships between agricultural practices, soil health, nematodes, and crop yield. In order to enhance the adoption of best practices to overcome the challenges, we need to understand farmer's perceptions of these multifaceted relationships between PPN and soil health. In order to understand the thought process of farmers and farmer perceptions on 'best' practices, we used a fuzzy cognitive mapping approach to mental model how farmers view the influence of these practices on potato productivity prior to demonstrating the results of the field experiments. Using a structured mental model protocol, we interviewed potato farmers. We evaluated the farmers' perceptions on the relationships between various agronomic practices on PPN, soil health, potato yield, and the likelihood of the farmer adopting the practices. The farmers' mental maps showed they perceive the use of biocontrol, nematicides and compost to negatively impact PPN while the use of certified seeds, chicken litter and fertilizer positively impact PPN. A squashing function was applied to run intervention scenarios for five agricultural practices: certified seeds, compost, biocontrol, chicken litter and nematicide. The output impact on yield, PPN and soil health are mostly similar directionally except for application of compost, certified seeds and pesticides. Experts’ map shows certified seeds and compost reduce PPN. Farmer’s map showed using certified seeds increase yield. Understanding the knowledge gaps of farmers and experts helps tailor the development of extension activities to ameliorate knowledge gaps and promote higher rates of adoption of 'best' practices that will lead to enhanced soil health, higher potato yield, lower PPN and improved farmer livelihoods. The results of more weights given to the perceptions of agronomic practices toward soil health are indicative of better understanding of these practices on soil health than understanding of the impact on PPN. If reducing yield loss to PPN is the goal of the project, evidence-based training on the 'best' practices is needed by these smallholder farmers. The studied regions lay over Mollisol and Andisol soil groups. The Mollisols are at 3,200 m to 3,353 m and Andisols around 2,896 m altitude. The experiment in each region consisted of testing the effects of amending soils either with or without bio-mix and 0, 318, or 454 kg composted chicken manure at eight locations. The bio-mix (BioCopia) consisted of isolates of Purpureum and Bacillus to suppress harmful nematodes. Over the growing season, nematode abundance averaged about 300 to 600 individuals/100 cm3 of soil. Herbivores accounted for 20-40% of the nematode fauna in both regions. Herbivores, predators and omnivores tended to increase with time in Andisols plots more so than in Mollisols plots. Soil pH in the Andisols averaged 5.5 and 5.0 in Mollisols. P was similar in both soils. While K was above recommended levels in both soils, K was higher in Andisols than in Mollisols. Percent soil organic matter and C:N ratio were significantly higher in Mollisols than in Andisols, suggesting nutritional imbalances between the soil groups. Yet, based on the Ferris SFW model, the agroecosystem suitability profile of the two soil groups fell into Quadrant C - needing biological activity for nutrients to be released. The combination of the biophysiochemical data suggest that neither soil group has suitable conditions, but the soil groups differ in the practices needed to achieve ideal agroecosystem conditions - profile outcomes falling into Quadrant B of the SFW model. At midseason, striking differences in plant growth between compost and non-compost amendment treatments existed in both regions. These differences were reflected in yield although not statistically significant (P >0.05). Cyst nematode population density trended similar to yield, with both parameters higher in Andisols than in Mollisols. Soil pH and percent organic matter (%OM) did not show significant correlation with either yield nor the number of cysts across amendments. However, yield, soil pH and %OM were positively and significantly correlated in Andisols, suggesting differences between the soil groups. As part of assessing integrated efficiency of the soil amendment treatments and potential sustainability of the outcomes, cyst (x-axis) and yield (y-axis) were expressed as a percent of control and fitted to the fertilizer use efficiency (FUE) model. Based on the FUE model, the data fell into Quadrant B - soil amendments are increasing cyst population density and yield in both soil groups. The data suggest the need for additional measures for managing potato cyst nematodes without compromising biological processes that increase %OM or yield response.  Some established southern New Mexico vineyards are experiencing yield reductions of >50% attributed to M. incognita. In December 2017, Pratylenchus vulnus populations 10-fold greater than the damage threshold were recovered from a declining Riesling planting in northern NM.  Due to growing numbers of small, boutique vineyards and wineries in New Mexico and surrounding states, a survey of nematode populations associated with healthy, transitional, and declining vines in 25 vineyards was conducted in 2018. Results found that 44% of vineyards contained root-knot populations exceeding damage thresholds, with M. incognita occurring the south and M. hapla in the areas north of Albuquerque.  Xiphinema americanum was the most prevalent PPN, exceeding thresholds in 64% of vineyards statewide.  Pratylenchus species exceeded thresholds in 32% of vineyards, mostly in the northern half of the state.  Objective 3:  Develop and assess nematode management strategies in agricultural production systems.                The management of plant-parasitic nematodes can follow several paths from host plant resistance to chemical controls to biological controls. Some approaches integrate multiple paths. Root-knot nematode resistance in carrot is being integrated with pesticide applications. There are five regions in the carrot genome identified so far that hold resistance determinants. There are a number of resistance sources in carrot and advanced material is continuously released to the vegetable seed industry. M. javanica resistance and M. incognita resistance are controlled by different genes, at least in part, because different determinants have been identified in the carrot genome through QTL analysis. In some carrot populations the M. javanica resistance gene Mj1 is fixed (homozygous) but resistance to M. incognita is segregating. M. hapla resistance was found in carrot varieties Homs and different Brasilia parents. Of 691 carrot lines from the USDA germplasm collection screened for resistance to M. incognita, 100 lines with? putative resistancewere identified in field-screens. Of these, 21 lines have some resistance with 10 lines having high resistance after re-testing in controlled greenhouse screens. These lines are from around the world including southeast Asia, India and South Africa. Within the 100 lines with putative M. incognita resistance, a subset were identified to also carry M. hapla resistance. Tioxazafen (Nemastrike) from Bayer AG, a public partner in the project, is being tested as a soil incorporated pre-plant treatment in conjunction with resistance. Initial results from this combination of chemicals and resistance indicate that the nematicide treatment has strong efficacy in protecting the carrot taproot from root-knot nematode galling damage. This is a promising integrated control.  The soybean cyst nematode (SCN, Heterodera glycines) is the most destructive plant-parasitic nematode in soybean-growing regions around the world. Different fungal genera have been associated with cysts of SCN and Corynespora cassiicola is one of them. The nematicidal activity of twelve culture filtrates obtained from C. cassiicola isolates was investigated in vitro against SCN J2s. Twelve C. cassiicola isolates were recovered from cotton and soybean symptomatic leaves sampled at different locations in Alabama. Culture filtrates were placed into 96-well plates with SCN J2s and incubated at room temperature for 48 hours. SCN mortality ranged from 14.4 to 64.3% for the culture filtrates. Of 12 culture filtrates, three (PBU04, FHP22, and LIM13) were significantly more effective in killing SCN J2s, compared to other culture filtrates and untreated control (Ƥ ≤ 0.05). Future investigation is needed to identify the compounds present in these bioactive culture filtrates from C. cassiicola with potential nematicidal activity against juveniles of H. glycines, as well as the potential of activity against other plant-parasitic nematodes species.  Plant Growth Promoting Rhizobacteria (PGPR) are rhizosphere bacteria known to promote plant growth and inhibit different plant pathogens including plant-parasitic nematodes through production of a range of secondary metabolites. Recently, there has been much interest in identifying these metabolites as a biological alternative to chemical nematicides. In total, 663 PGPR strains were assayed for their nematicidal activity by co-culturing them with 30-50 second stage juveniles (J2) of Heterodera glycines. Their nematicidal effect was determined by observing the response of juveniles to Na2CO3. The juveniles changed their body shape from straight to curled or hook-shaped and showed quick movements within 2 minutes of addition of 1 µl of 1 N Na2CO3 if alive while dead ones did not respond. Eight PGPR strains showing the highest effect on J2s after 48 hours of co-culture were grown in Tryptic Soy Agar (TSA) for 10 days. The cell biomass (≈100 mg) from these plates were collected in 1ml sterile water, and the cells were lysed by repeated exposure to boiling (in water bath) with intermittent cooling in ice for 15 minutes. The lysis was followed by removal of cell materials by centrifugation at 4,500 rpm for 5 minutes. The cell-free supernatants were collected as crude extracts, and their efficacy against the J2s was tested in vitro in 96 well plates. The in vitro results indicated that of the eight strains tested, five strains: Bacillus altitudinis (Bal13), B. mojavensis (Bmo3), B. safensis (Bsa27), B. aryabhattai (Bar46), and B. subtilis subsp. subtilis (Bsssu2) produced metabolites that were significantly more toxic to J2s of H. glycines compared to the control and other PGPR strains tested (P ≤ 0.05). Chemical nematicides continue to be an important management tool for plant-parasitic nematodes. Columbia Root-knot Nematodes (CRKN, Meloidogyne chitwoodi) infect potato tubers and cause quality defects consisting of galling of the tuber surface and small brown spots that surround the female and egg mass inside the tuber. Furthermore, CRKN is a quarantined pest in some countries. Control of CRKN has been challenging as some products are not always adequate alone and there has been an inadequate supply of products in recent years. Recently, several new, less toxic, nematicides have been developed and are being tested. In the first trial Velum Prime (Fluopyram) and Movento (Spirotetramat) were tested. Untreated plots had a high level (65%) of culled tubers. A standard Vydate program consisting of an in-furrow application at planting plus chemigation applications at 1,440 degree-days and every 2 weeks until late season, reduced culls to an acceptable level (10%).  Replacing the in-furrow Vydate application with Velum Prime in-furrow was very good either with (7% culls) or without (2% culls) an additional application of Velum Prime at a six-inch rosette (May 23). Replacing the Velum Prime in-furrow treatment with a Velum Prime application at rosette was not acceptable (27% culls). Replacing the Velum Prime in-furrow treatment with a Velum Prime application at rosette and four weeks later (June 20) was also not acceptable (24% culls). A treatment with Velum Prime in-furrow and at rosette with applications of Movento instead of Vydate on July 4 and July18 was not acceptable (24% culls). This same treatment without Vydate or Velum Prime in-furrow was no different than the untreated control (59% culls). The second trial was organized around broadcast preplant incorporated (PPI) applications (April 19) of Nimitz (Fluensulfone). There were no statistical differences between treatments so the following comments are based on the relative ranking of treatment means. Untreated plots had a high level (67%) of culled tubers. A standard Vydate program consisting of an application in-furrow at planting plus chemigation applications at 1,440 degree-days (base soil temperature 41 F, July 4) and every two weeks until September 12 did not reduce culls to an acceptable level (46%). Nimitz PPI alone did not reduce the level of nematode culled tubers (67%). Velum Prime in-furrow alone reduced nematode culled tubers slightly (46%) but Nimitz PPI plus Velum Prime in-furrow had little effect on culled tubers (57%). Nimitz PPI plus Velum Prime in-furrow plus the in-season Vydate program starting July 4 reduced nematode culls substantially (30%). Nimitz PPI plus in-furrow Velum Prime plus two early season (June 13, July 4) applications of Movento was the best treatment in this trial (28% culled tubers).  However, Nimitz PPI plus in-furrow Velum Prime plus two late season applications of Movento was not as effective (37% culled tubers).  The newer nematicides Nimitz® and Velum 1® both proved effective at significantly reducing M. incognita RF factor compared to untreated control plots on pinto bean eight weeks after emergence in microplot studies in NM.  The 3.5 pt/A and 5.0 pt/A rates of Nimitz provided better nematode control than 7.0 pt/A Nimitz or Velum 1.  The significant reduction in RF with 3.5 pt/A Nimitz persisted through harvest.  Pinto bean yields were lower in all root-knot infested plots compared to noninfested plots, regardless of nematicide treatment.   Beyond resistance genes, other genes are involved in the nematode host interaction. There are early associated patterns or Plant Innate Immunity patterns that trigger immunity. Effectors such as resistance proteins trigger the plant immunity. Tomatoes also have pathogen recognition factors for nematodes. Susceptible plants have perception pathways, so silencing these pathways results in greater susceptibility to the nematode. We do not know what is being recognized in the nematode systems yet. The 2018 Nobel Prize was for work in cancer on negative immune regulation - plants have a similar type of immune regulation. So we may have a similar system in plants for nematodes. The immune system has “brakes” to control the immune response to prohibit autoimmune diseases. Using the CRISPR/CAS9 system we could target the recognition genes or the break genes to enhance the immune system and confer resistance to nematodes. A transcriptome analysis on M. chitwoodi infected potato roots demonstrated that there are at least 167 nematode genes that are significantly up-regulated in expression during potato infection. These genes are being further investigated to determine if they encode proteins with important roles in nematode pathogenicity. The goal is to use these nematode genes as probes in plant cells to find their host cell interaction partners. The interaction partners are involved in controlling host susceptibility to nematodes. Genes in the syncytia of resistant and susceptible soybean shows what is common and what is unique. Induction of expression of one gene induces expression of all the genes in the cascade because of cross communication. A similar situation occurs with suppression of one gene where suppression of other genes will occur. α-SNAPs are targets for suppression as these genes are for vesicle transport system and defense.

Publications

Journal Articles   Ahmed, F.A., B.S. Sipes, and A.M. Alvarez. 2017. Postharvest diseases of tomato and natural products for disease management. African Journal of Agricultural Research: 12:684-691. DOI: 10.5897/AJAR2017.12139   Avelar, Sofia, Drew W. Schrimsher, Kathy S. Lawrence, and Judith K. Brown. 2018. First report of cotton leafroll dwarf virus associated with cotton blue disease symptoms in Alabama. Plant Disease. <a href="https://doi.org/10.1094/PDIS-09-18-1550-PDN">https://doi.org/10.1094/PDIS-09-18-1550-PDN</a>   Chan, C., B. Sipes, A. Ayman, X. Zhang, P. LaPorte, F. Fernandes, A. Pradhan, J. Halbrendt, and P. Roul. 2017. Efficiency of conservation agriculture production systems for smallholders in rainfed uplands of India: A transformative approach to food security. Land 6:58, doi:10.3390/land6030058.   Lawaju, B.R., Lawrence, K.S., Lawrence, G.W., and Klink, V.P. 2018. Harpin-inducible defense signaling components impair infection by the ascomycete Macrophomina phaseolina. Plant Physiology and Biochemistry 129:331–348.   Leelarasamee, N., Lei Zhang, and Cynthia Gleason. 2018. The root-knot nematode effector MiPFN3 disrupts plant actin filaments and promotes parasitism. PLOS Pathogens 14(3): e1006947. doi: 10.1371/journal.ppat.1006947.   Ndeve, A. D., W. C. Matthews, J. R. P. Santos, B.-L. Huynh and P. A. Roberts. . Broad-based root-knot nematode resistance identified in cowpea gene-pool two. Journal of Nematology 50:545-558. Doi: 10.21307/jofnem-2018-046   Powers, Thomas, Andrea Skantar, Tim Harris, Rebecca Higgins, Peter Mullin, Saad Hafez, Zafar Handoo, Tim Todd, and Kirsten Powers. 2019. DNA barcoding evidence for the North American presence of alfalfa cyst nematode, Heterodera medicaginis. Journal of Nematology 51 (in press).   Powers, T.O., Harris, T., Higgins, R., Mullin, P., and Powers, K. 2018. Discovery and identification of Meloidogyne species using COI DNA barcoding. Journal of Nematology 50 DOI: 10.21307/jofnem-2018-029.   Pradhan, A., C. Chan, P.K. Roul, J. Halbrendt, and B. Sipes. 2018. Potential of conservation agriculture (CA) as climate smart technology for food security under rainfed uplands of India: A transdisciplinary approach. Agricultural Systems 163:27-35.   Munawar, M., Powers, T. O., Tian, Z., Harris, T., Higgins, R., and Zheng, J. 2018. Description and distribution of three Criconematid nematodes from Hangzhou, Zhejiang Province China. Journal of Nematology 50 DOI: 10.21307/jofnem-2018-010.   Munawar, Maria, Ruihang Cai, Weimin Ye, Thomas O. Powers, and Jingwu Zheng. 2018. Description of Gracilacus paralatescens n. sp. (Nematoda: Paratylenchinae) found from the rhizosphere of bamboo in Zhejiang, China. Journal of Nematology 50 DOI: 10.21307/jofnem-2018-041.   Santos, J.R.P., Ndeve A., Huynh B.L., Matthews W.C., and Roberts P.A. 2018. Transcriptome analysis of cowpea near-isogenic lines reveals candidate genes for root-knot nematode resistance. PLoS ONE 13 (1): e0189185.   Till, Stephen, Kathy Lawrence and Patricia Donald. 2018. Nematicides, Starter Fertilizers, and Plant Growth Regulators Implementation into a Corn Production System. Plant Health Progress 19: 242-253. <a href="https://doi.org/10.1094/PDIS-09-18-1550-PDN">https://doi.org/10.1094/PDIS-09-18-1550-PDN</a>   Wang C, Ulloa M, Duong TT, Roberts PA. 2017. QTL analysis of transgressive nematode resistance in tetraploid cotton reveals complex interactions on chromosome 11 regions. Frontiers in Plant Science 8: 1979 p.1-12.  <a href="http://doi.org/10.3389/fpls.2017.01979">doi: 10.3389/fpls.2017.01979</a>   Xiang, Ni, K.S. Lawrence, and P.A. Donald. 2018. Biological control potential of plant growth-promoting rhizobacteria suppression of Meloidogyne incognita on cotton and Heterodera glycines on soybean: A review.  Journal of Phytopathology. 2018:1–10. <a href="https://doi.org/10.1111/jph.12712">https://doi.org/10.1111/jph.12712</a>   Xiang, Ni, K.S. Lawrence, J.W. Kloepper, and P.A. Donald. 2018. Biological control of Rotylenchulus reniformis on soybean by plant growth-promoting rhizobacteria. Nematropica: 48:116-125.    Zhang, Lei and Cynthia Gleason. 2018. Loop-mediated isothermal amplification for the detection of Meloidogyne chitwoodi and M. fallax. Plant Disease doi: 10.1094/PDIS-01-18-0093-R   Abstracts, Proceedings and Conferences   <ol start="2018"> <li>Chan, P. LaPorte, J. Chan-Dentoni, B.S. Sipes, A. Sanchez, A. Sacbaja, and H. Melakeberhan. 2018. Assisting smallholder farmers in adopting integrated nematode-soil health management: I – Fuzzy cognative mapping to understand grower perceptions. Journal of Nematology 50: in press.</li> </ol>   Dyer, David R., Kathy S. Lawrence and Drew Schrimsher.  2018. Yield loss to cotton cultivars due to reniform and root-knot nematode and the added benefit of Velum Total. Proceedings of the 2018 Beltwide Cotton Conference Vol. 1: 511-514. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm</a>   Dyer, D.,  K. S. Lawrence, S. Till, W. Groover, N. Xiang, M. Rondon, K. Gattoni, C. Norris. 2018. Cotton variety evaluation with and without Velum Total for reniform management in north Alabama, 2017 Report No. 12:N010 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N010.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N010.pdf</a>   Dyer, D.,  K. S. Lawrence, S. Till, W. Groover, N. Xiang, M. Rondon, K. Gattoni. 2018. Cotton variety evaluation with and without Velum Total for root-knot management in Alabama, 2017. Report No. 12:N011 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N011.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N011.pdf</a>   Dyer, D.,  K. S. Lawrence, S. Till, W. Groover, N. Xiang, M. Rondon, and K. Gattoni. 2018. Effects of starter fertilizers, plant hormones, and nematicides to manage reniform nematode damage in Alabama, 2017. Report No. 12:N012 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N012.pdf   Dyer, D.,  K. S. Lawrence, S. Till, W. Groover, N. Xiang, M. Rondon, K. Gattoni, M. Pegues. 2018. Cotton variety evaluation with and without Velum Total for root-knot nematode management in south Alabama, 2017. Report No. 12:N013 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N013.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N013.pdf</a>   Dyer, D.,  K. S. Lawrence, S. Till, W. Groover, N. Xiang, M. Rondon, K. Gattoni, C. Norris. 2018. Cotton variety evaluation with and without Velum Total for reniform management in north Alabama, 2017 Report No. 12:N014 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N014.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N014.pdf</a>   Dyer, D.,  K. S. Lawrence, S. Till, W. Groover, N. Xiang, M. Rondon, K. Gattoni. 2018. Cotton variety evaluation with and without Velum Total for root-knot nematode management in Alabama, 2017. Report No. 12:N019 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N019.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N019.pdf</a>   Dyer, D.,  K. S. Lawrence, S. Till, W. Groover, N. Xiang, M. Rondon, K. Gattoni, C. Norris. 2018. Evaluation of a by-product fertilizer to increase plant growth and decrease reniform population density on cotton in Alabama, 2017. Report No. 12:N020 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N020.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N020.pdf</a>   Faske, Travis R., Tom W. Allen, Gary W. Lawrence, Kathy S. Lawrence, Hillary L. Mehl, Charlie Overstreet, and Terry A. Wheeler. 2018. Beltwide Nematode Research and Education Committee Report on Cotton Cultivars and Nematicides Responses in Nematode Soils, 2017. Proceedings of the 2018 Beltwide Cotton Conference Vol. 1: 811-814. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm</a>   Gattoni, Kaitlin, Ni Xiang, Kathy Lawrence and Joseph Kloepper. 2018. Systemic Induced Resistance to the root-knot nematode cause by Bacillus spp.  Proceedings of the 2018 Beltwide Cotton Conference Vol. 1: 506-510. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm</a>   Gattoni, Kaitlin, N Xiang, K. S. Lawrence, W. Groover, A. Till, D. Dyer, M. N. Rondon, and M. Foshee. 2018. Evaluation of cotton nematicide combinations and rates for reniform nematode management in northern Alabama, 2017. Report No. 12:N040 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N040.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N040.pdf</a>   Gattoni, Kaitlin, N Xiang, K. S. Lawrence, W. Groover, A. Till, D. Dyer, M. N. Rondon, and M. Foshee. 2018. Evaluation of cotton nematicide combinations for reniform nematode management in northern Alabama, 2017 Report No. 12:N041 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N041.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N041.pdf</a> Giese, William, J. M. Beacham, S. H. Thomas, Sutherland, T. O. Powers, L. Roberts, D. Goodrich, M. Kersten, and A. Bennett.  2018. Plant parasitic nematodes associated with New Mexico vineyards. Journal of Nematology 50: in press.   Groover, Will, K.S. Lawrence, N. Xiang, S. Till, D. Dyer, M. Foshee, M. Rondon, K. Gattoni. 2018. Soybean variety and nematicide evaluation in a reniform infested field in northern Alabama, 2017. Report No. 12:N004 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N004.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N004.pdf</a>   Groover, Will, K.S. Lawrence, N. Xiang, S. Till, D. Dyer, M. Foshee, M. Rondon, K. Gattoni. 2018. Nematicide and fertilizer combinations for root-knot nematode management on soybean in northern Alabama, 2017. Report No. 12:N005 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N005.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N005.pdf</a>   Groover, Will, K.S. Lawrence, N. Xiang, S. Till, D. Dyer. 2018. Nematicide and fertilizer combinations for root-knot nematode management on soybean in central Alabama, 2017. Report No. 12:N006 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N006.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N006.pdf</a>   Groover, Will and Kathy S. Lawrence. 2018. Meloidogyne Spp. Identification and distribution in Alabama crops via the differential-host test and molecular analysis. Proceedings of the 2018 Beltwide Cotton Conference Vol. 1: 503-505. National Cotton Council of America, Memphis, TN. http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm   Groover, Will, K.S. Lawrence, N. Xiang, S. Till, and D. Dyer. 2018. Fertilizer and nematicide combination for reniform nematode management on soybean in central Alabama, 2017 Report No. 12:N008 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N008.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N008.pdf</a>   Groover, Will, K.S. Lawrence, S. Till, D. Dyer, and N. Xiang. 2018. Fertilizer and nematicide combination evaluations for root-knot nematode management in southern Alabama, 2017 Report No. 12:N009 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N009.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N009.pdf</a>   Groover, Will, K.S. Lawrence, N. Xiang, S. Till, D. Dyer, M. Foshee, M. Rondon, and K. Gattoni. 2018. Soybean variety and nematicide evaluation in a root-knot nematode infested field in southern Alabama, 2017. Report No. 12:N007 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N007.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N007.pdf</a>   Kakaire, S., A. Sanchez, B.S. Sipes, C.-L. Lee, A. Sacbaja, C. Chan, and H. Melakeberhan. 2018. Assisting smallholder farmers in adopting integrated nematode-soil health management: III – Changes in soil biophysiochemistry. Journal of Nematology 50: in press.   Klink VP. 2018. A harpin elicitor induces the expression of a CC-NB-LRR defense signaling gene and others functioning during defense to different parasitic nematodes. Plant and Animal Genomes Meeting XXVI. San Diego, CA.   LaPorte, P., C. Chan, B.S. Sipes, A. Sanchez, A. Sacbaja, and H. Melakeberhan. 2018. Assisting smallholder farmers in adopting integrated nematode-soil health management: II – Fuzzy cognative mapping identifying gaps between experts and farmers perceptions. Journal of Nematology 50: in press.   LaPorte, P., J. Chan-Dentoni, C. Chan, B. Sipes, H. Melakeberhan, and A. Mejia. 2018. Perception of potato practices and their impacts by farmers in Guatemala using fuzzy cognitive mapping. 30th International Conference of Agricultural Economics. Vancouver, Canada.   LaPorte, P., B. Sipes, H. Melakeberhan, C. Chan, A. Sanchez-Perez, and A. Sacbaja. 2017. An interdisciplinary assessment of integrated nematode-soil health management for smallholder potato farming systems in the western highlands of Guatemala. Journal of Nematology 49:510.   Lawrence, K., Austin Hagan, Randy Norton, J. Hu, Travis R. Faske, Robert B. Hutmacher, John Muller6, Ian Small, Z. Grabau, Robert C. Kemerait, Charlie Overstreet, Paul Price, Gary W. Lawrence, Tom W. Allen, Sam Atwell, John Idowa, Randy Bowman, Jerry R. Goodson, Heather Kelly, Jason Woodward, Terry Wheeler and Hillary L. Mehl. 2018.  Cotton Disease Loss Estimate Committee Report, 2017. Proceedings of the 2018 Beltwide Cotton Conference Vol. 1: 161-163. National Cotton Council of America, Memphis, TN.  <a href="http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm</a>   Lawrence. K., N. Xiang, W. Groover, S. Till, D. Dyer, K. Gattoni, and M. Rondon. 2018. Cotton seeding rate and fungicide combinations for cotton seedling disease management in north Alabama, 2017. Report No. 12:N021 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N021.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N021.pdf</a>   Lawrence. K., N. Xiang, W Groover, S. Till, D. Dyer, K. Gattoni, and M. Rondon. 2018. Cotton nematicide combinations for reniform management in north Alabama, 2017. Report No. 12:N022 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N022.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N022.pdf</a>   Lawrence. K., N. Xiang, W Groover, S. Till, D. Dyer, K. Gattoni, and M. Rondon. 2018. Cotton nematicide combinations for reniform management in central Alabama, 2017. Report No. 12:N023 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N023.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N023.pdf</a>   Lawrence. K., N. Xiang, W Groover, S. Till, D. Dyer, K. Gattoni, and M. Rondon. 2018. Cotton nematicide combinations for reniform management in north Alabama, 2017. Report No. 12:N024 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N024.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N024.pdf</a>   Moye, Hayden Hugh, Ni Xiang, Kathy S. Lawrence, Joyce Tredaway and Edzard van Santen. 2018. Birdsfoot Trefoil (Lotus corniculatus) Cover for Alabama Cropping Systems: Fungal Diseases, Susceptibility to Nematodes, and Efficacy of Herbicides. Proceedings of the 2018 Beltwide Cotton Conference Vol. 1: 497-502. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm</a>   Moye, H. H., K.S. Lawrence, N. Xiang, W. Groover, S. Till, D. Dyer, M. Foshee, K. Gattoni, and M. Rondon. 2018. Reniform nematode control on cotton using nematicide combinations in north Alabama, 2017. Report No. 12:N025 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N025.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N025.pdf</a>   Niraula, P.M., Lawaju, B.R., McNeece, B.T., Pant, S.R., Sharma, K., Al-Jaafri, W.A., Long, D.H., Lawrence, K.S., Lawrence, G.W., and Klink, V.P. 2018. A functional genomic screen for defense genes in Glycine max as it relates to parasitism by the plant parasitic nematode Heterodera glycines. American Phytopathological Society.   Rondon, Marina, Ni Xiang, Jenny Koebernick and Kathy Lawrence. 2018. Detection of Cassiicolin-Encoding Genes in Corynespora cassiicola Isolates from Cotton and Soybean. Proceedings of the 2018 Beltwide Cotton Conference Vol. 1: 493-496. National Cotton Council of America, Memphis, TN. http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm   Rondon, Marina Nunes, N. Xiang, K.S. Lawrence, S. Till, W. Groover, D. Dyer, K. Gattoni. 2018. Evaluation of seed treatments fungicides for damping-off control in northern Alabama, 2017. Report No. 12:ST002 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/ST002.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/ST002.pdf</a>   Schrimsher, Drew, Brad Meyer, Kathy Lawrence and Trey Cutts. 2018. Cotton Virus Associates with Whiteflies or Something Else? Proceedings of the 2018 Beltwide Cotton Conference Vol. 1: 925. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm</a>   Sharma, K. 2018. Co-regulation of the Glycine max soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE)-containing regulon occurs during defense to a root pathogen. Nepalese Agriculture Professionals in America, Biennial conference.   Sharma, K. 2018. Co-regulation of the Glycine max soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE)-containing regulon occurs during defense to a root pathogen. The 17th Biennial Conference on the Molecular and Cellular Biology of the Soybean.   Sharma, K. 2018. Co-regulation of the Glycine max soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE)-containing regulon occurs during defense to a root pathogen. Second Annual Summer Student Science Symposium, Mississippi Academy of Sciences Till, Stephen R., Kathy S. Lawrence and Drew Schrimsher. 2018. A Cost-Effective Approach for Combining Nematicides, Starter Fertilizers, and Plant Growth Regulators in order to Create a Sustainable Management System for the Southern Root-Knot Nematode, Meloidogyne incognita. Proceedings of the 2018 Beltwide Cotton Conference Vol. 1: 515-514. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm</a>   Till, S. R., K.S. Lawrence, N. Xiang, W. Groover, D. Dyer, M. Foshee, K. Gattoni, and M. Rondon. 2018. The effect of Counter 20G and corn hybrid selection on early corn plant growth and yield in the presence of root-knot nematode in Alabama, 2017. Report No. 12:N026 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N026.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N026.pdf</a>   Till, S. R., K.S. Lawrence, N. Xiang, W. Groover, D. Dyer, M. Foshee, K. Gattoni, and M. Rondon. 2018. Corn hybrid and nematicide evaluation in root-knot nematode infested soil in central Alabama, 2017. Report No. 12:N027 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N027.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N027.pdf</a>   Till, S. R., K.S. Lawrence, N. Xiang, W. Groover, D. Dyer, M. Foshee, K. Gattoni, M. Rondon. 2018. Evaluation of nematicides, starter fertilizers, and plant growth regulators for root-knot nematode management in south Alabama, 2017. Report No. 12:N028 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N028.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N028.pdf</a>   Till, S. R., K.S. Lawrence, N. Xiang, W. Groover, D. Dyer, M. Foshee, K. Gattoni, M. Rondon, and M. Foshee. 2018. Corn variety evaluation with and without Counter 20G for root-knot management in south Alabama, 2017. Report No. 12:N029 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN.  <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N029.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N029.pdf</a>   Xiang, Ni, K. S. Lawrence, W. Groover, S. Till, D. Dyer, and K. Gattoni. 2018. Evaluation of BioST nematicide for root-knot nematode management on corn in central Alabama, 2017. Report No. 12:N032 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN.  <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N032.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N032.pdf</a>   Xiang, Ni, K. S. Lawrence, W. Groover, S. Till, D. Dyer, K. Gattoni. 2018. Evaluation of BioST nematicide for root-knot nematode management on cotton in central Alabama, 2017. Report No. 12:N033 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N033.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N033.pdf</a>   Xiang, Ni, K. S. Lawrence, W. Groover, S. Till, D. Dyer, and  K. Gattoni. 2018. Evaluation of BioST nematicide for reniform nematode management on cotton in north Alabama, 2017. Report No. 12:N034 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N034.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N034.pdf</a>   Xiang, Ni, K. S. Lawrence, W. Groover, S. Till, D. Dyer, and K. Gattoni. 2018. Evaluation of BioST nematicide for root-knot nematode management on soybean in central Alabama, 2017. Report No. 12:N035 DOI: 11.1094/PDMR12 The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N035.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N035.pdf</a>

Impact Statements

• Understanding the knowledge gaps of farmers and experts assists in tailoring extension activities to promote higher rates of adoption of 'best' practices by livelihoods.

Date of Annual Report: 01/13/2020

Report Information

Annual Meeting Dates: 11/14/2019 - 11/15/2019
Period the Report Covers: 01/01/2019 - 12/31/2019

Participants

Beacham, Jacqueline, New Mexico State University; Dandurand, Louise-Mary, University of Idaho; Gleason, Cynthia, Washington State University; Hafez, Saad, University of Idaho; Ingham, Russell, Oregon State University; Kaloshian, Isgouhi, University of California-Davis; Klink, Vince, Mississippi State University; Lawrence, Kathy, Auburn University; Melakeberhan, Haddish, Michigan State University; Powers, Tom, University of Nebraska; Roberts, Phil, University of California-Riverside; Siddique, Shahid, University of California-Davis; Sipes, Brent, University of Hawaii; Thomas, Stephen, New Mexico State University

Brief Summary of Minutes

W4186 Minutes

14-15 November 2019

Riverside, CA

Present: Phil Roberts, Isgouhi Kaloshian, Saad Hafez, Vince Klink, Russ Ingham, Haddish Melakeberhan, Cynthia Gleason, Jacki Beacham, Brent Sipes, Shahid Siddique

Meeting Summary: Group conversation regarding accomplishments of previous year and future plans for project renewal.

Accomplishments

Multistate Project W4186 2019 Annual Report   Project/Activity Number:      W4186 Project/Activity Title:            Variability, Adaptation and Management of Nematodes Impacting Crop Production and Trade Period Covered:                     2019 Date of This Report:              January 13, 2020 Annual Meeting Date(s):       November 14-15, 2019     Participants: Beacham, Jacqueline (New Mexico State University) Dandurand, Louise-Mary (University of Idaho) Gleason, Cynthia (Washington State University) Hafez, Saad (University of Idaho) Ingham, Russell (Oregon State University) Kaloshian, Isgouhi (University of California-Davis) Klink, Vince (Mississippi State University) Lawrence, Kathy (Auburn University) Melakeberhan, Haddish (Michigan State University) Powers, Tom (University of Nebraska) Roberts, Phil (University of California-Riverside) Siddique, Shahid (University of California-Davis) Sipes, Brent (University of Hawaii) Thomas, Stephen (New Mexico State University)     Accomplishments and Impacts     Objective 1:   Characterize genetic and biological variation in nematodes relevant to crop production and trade. Critical to nematode management practices is the rapid and accurate identification of nematodes for regulatory and management purposes. However, this objective is a major challenge. The following activities have been performed regarding objective 1. Plant-parasitic nematodes, of which 4,100 species have been described, are estimated to cause 100 billion USD in agricultural loss per year. Economic, health, and environmental considerations make natural host plant resistance a preferred strategy for nematode control, but there are limitations to this approach. In many cases, the resistance conferred by resistance genes is partial, and some of the nematodes are able to survive. Similarly, nematode resistance genes are often effective against only one or a few species, whereas plants are exposed to several pathogens in the field. Another concern is the emergence of pathotypes that can overcome resistance. In view of all these limitations, it is important to identify additional biological mechanisms that can be used to develop novel and durable crop resistance against nematodes. Fundamental to achieving this goal is understanding the mechanisms by which plants recognize and defend themselves against nematodes. The plant cell plasma membrane contains pattern recognition receptors (PRRs) that mediate recognition of evolutionarily conserved molecules from bacteria, oomycetes, or fungi. A plethora of studies have focused on the recognition and activation of PTI responses during various types of plant -pathogen interactions. The goal of the current project is to identify plant receptors that are implicated in nematode perception. To identify those receptors, Arabidopsis thaliana plants were infected with cyst nematodes and changes in gene expression for all membrane-receptors was measured. In this way, we have so far identified 108 membrane-localized receptors whose expression is significantly upregulated during the invasion and induction stages of nematode infection. Knock-out mutants for approximately 50 genes were tested for nematode infection and 5 receptors were identified that are implicated in nematode susceptibility. The mechanism behind the role of receptors in nematode recognition is being investigated. The research plan focuses initially on the model plant A. thaliana and its interaction with cyst nematode and root-knot nematode. However, the knowledge gained will be transferred to crop plants during the subsequent years, particularly to soybean (Glycine max), almond (Prunus dulcis), tomato (Lycopersicon esculentum) and sugar beet (Beta vulgaris). In collaboration with a Nebraska-based biotechnological company, MatMaCorp (<a href="http://www.matmacorp.com/">http://www.matmacorp.com/</a>) we have developed a custom test to simultaneously detect and identify four economically important cyst species. In about two hours, we are able to detect and identify Heterodera avenae (cereal cyst), H. glycines (soybean cyst), H. medicaginis (alfalfa cyst), and H. schachtii (sugarbeet cyst) from soil or root samples, and differentiate them from H. trifolii (clover cyst) or other closely-related nematodes. Each of these cyst nematode species have been observed in the western Great Plains states, and potentially can coexist in fields with cropping strategies that include host plants of multiple species. Barley (Hordeum vulgare), for example, a preferred host of the cereal cyst nematode, is often grown in rotation with sugar beet. Many sugar beet fields in the west have populations of sugar beet cyst nematode. The diagnostic test can be conducted on a single juvenile extracted from the soil or community DNA extracted from the nematode population. No DNA extraction is necessary for working with single infective juveniles. The DNA template is added to a lyophilized C-SAND assay that includes sequence-specific fluorescent probes for each of the four species. These reactions are processed and immediately analyzed on a Solas 8 portable device. We are currently conducting validation tests under a range of conditions. A second project completed and published was the survey of Pratylenchus species of the Great Plains. It was determined that P. neglectus is the most wide-spread species in the region occurring on most crops grown in the Great Plains. The second most frequently recovered was P. scribneri, which is found in most corns fields in the region. Both species co-occurred in approximately 20% of the fields. Pratylenchus alleni, P. penetrans, and P. zeae were observed in very low frequency (<1%) in the surveyed fields. A third project for which we contributed over 100 nematode datasets, each representing a nematode community analysis, resulted in a multi-investigator paper published in Nature, that estimated the global abundance and biomass of nematodes. Columbia Root-knot Nematodes (CRKN, Meloidogyne chitwoodi) infect potato (Solanum tuberosum) tubers and cause quality defects consisting of galling of the tuber surface and small brown spots that surround the female and egg mass inside the tuber. There is little tolerance for infection in tubers in domestic markets for fresh or processed potatoes and crops that exceed these tolerances may be devalued or rejected. Furthermore, there is no tolerance for infection in tubers intended for export to countries where CRKN is considered a quarantined pest and even one infested tuber can prevent a shipment from being exported. Several trials were conducted to test new management strategies using nematicides to control tuber damage from CRKN. After harvest, tubers were peeled and examined for CRKN infection. Any tuber with six or more infection sites was considered a cull. Metam sodium is considered a fumigant nematicide but has a lower vapor pressure than other fumigants and therefore does not move far from points of injection. This leaves areas in the soil that do not get adequately treated allowing nematodes to survive treatment. In this trial metam sodium was shanked-in 16 in. deep at 30 or 40 gallons per acre (gpa) and then the soil was mixed with a spader- tiller (or not) in an attempt to improve coverage. All treatments significantly reduced percentage of culled tubers compared to the control plots (99%) but none were acceptable. There were no differences between rate (30 gpa = 83%, 40 gpa = 76%) or spader (shank only = 84%, shank plus spader = 75%) treatments. Following a spader treatment of metam sodium at 40 gpa with an oxamyl standard program consisting of an in-furrow application at planting (April 19) followed by chemigation applications at emergence (May 15), 1,272 degree-days base 41F (June 12) and every two weeks until September 4 reduced percentage of culled tubers. There was no difference between ReTurn XL (29%) and Vydate C-LV (39%) formulations of oxamyl. A season-long program of Velum Prime (Fluopyram) in-furrow and at emergence plus in-season applications of Vydate C-LV reduced the percentage of culled tubers by 81% and was as good as beginning the program with Vydate in-furrow. In contrast to results from a similar trial in 2017, replacing two mid-season Vydate applications with Movento (Spirotetramat) did not reduce the level of control. In a trial testing broadcast preplant incorporated (PPI) applications of Nimitz (Fluensulfone), Velum Prime, and Vydate, Nimitz alone did not reduce the level of nematode-culled tubers and there was no difference between fall (78%) and spring (67%) applications (Untreated = 82%). Nimitz followed by Velum Prime in-furrow reduced the percentage of culled tubers when Nimitz was applied in the fall (56%) or the spring (45%). A standard Vydate program consisting of an in-furrow application at planting (April 19) followed by chemigation applications at emergence (May 15), 1,272 degree-days base 41F (June 12), and every two weeks until September 4 reduced percentage of culled tubers (19%). The best treatment was fall Nimitz followed by Velum Prime in-furrow, plus Vydate at 1,272 degree-days base 41F (June 12), and every two weeks until September 4 (3%). However, this was not significantly different from the standard Vydate program. Potatoes rank as one of the four most important staple crops on a global scale, and Washington produces a significant portion of the potatoes grown in the USA. Meloidogyne chitwoodi (also known as the Columbia root-knot nematode) is major problem for potato producers in this region. The nematode infects the potatoes and causes defects in the tuber that can significantly diminish the value of the crop. Because there are no commercially available crops with root-knot nematode resistance, we have been working to develop new forms of nematode controls. Treatment of potato roots with the defense elicitor peptide called Pep1 enhanced potato resistance against root-knot nematodes. In addition, we engineered the rhizobacteria Bacillus subtilis to produce and secrete Pep1. The bacterially-produced Pep1 also increased potato resistance against root-knot nematodes. Using various plant hormone mutants, we determined that the enhanced resistance in the plants is at least partially dependent on the defense hormones salicylic acid and jasmonic acid. Our work with the plant defense elicitor showed that the induced plant defenses were effective against different pathotypes of M. chitwoodi, suggesting a conserved resistance mechanism against the different strains of this nematode. The different pathotypes of M. chitwoodi found in the state of Washington have been an on-going issue because all pathotypes infect potatoes, but they differ in their ability to infect other hosts. Of these pathotypes, race 1 and race 2 differ in their ability to infect alfalfa (Medicago sativa). Alfalfa was previously recommended as a rotation crop to control M. chitwoodi. Race 1 cannot reproduce on alfalfa. However, a second race (Race 2) was discovered that can reproduce on alfalfa, diminishing the effectiveness of alfalfa crops as a nematode control tactic. We are using the genetic variability between races to develop markers so that growers can determine which race(s)/pathotypes are in their fields. We have performed transcriptome analyses on two of the most common pathotypes of M. chitwoodi in the state of Washington. The gene expression information was used to design primers that can distinguish race 1 and race 2 by a simple PCR. We are performing additional sequencing projects to develop more markers for four different races/pathotypes.              Objective 2:  Determine nematode adaptation processes to hosts, agro-ecosystems and environments. The procedures that have been developed so that nematodes can be measured can suffer from variation in the execution of the procedures among various laboratories and other factors including environmental conditions. This situation can lead to variation in the outcome of nematode measurements. A number of actions have been performed regarding objective 2. The northern root-knot nematode (NKRN), a problem in the northern hemisphere vegetable cropping systems, continues to be one of the major foci. Currently there are no commercially available resistant cultivars. The NRKN has parasitic variability that seems to be associated with soil types, and it occurs in varying soil health conditions. The agrobiological basis of NRKN parasitic variability remains unknown. The goal of this project is to understand how NRKN parasitic variability relates to the biological and physiochemical conditions in the environment in which it survives. The objective of this study is to establish any correlation between presence or absence of NRKN and soil health conditions, as indicated by nematode community, in different vegetable production regions of Michigan. To test the objective, 15 vegetable fields in three regions within the lower peninsula of Michigan (east, south-west and north-west) were selected. These fields represented muck and mineral soil types. In each of the fields, five 25 m2 area were flagged. Within each 25 m2, one geo-reference flag was randomly marked on the rows to collect rhizosphere soil and another flag about 30 cm away in between rows to represent bulk soil. As a control, five sampling points were flagged in an adjacent non-agricultural field. Each sample consisted of approximately 1 liter of composite of 10 cores around a flag. Nematodes were extracted from 100 cc sub-sample of each sample and identified to trophic and colonizer-persister groups to determine soil food web structure and function. The presence or absence of NRKN was tested by planting two weeks-old tomato seedlings cv Rutgers into 300 cc sub-sample from each of the bulk soil samples. The assumption was that the soil from 1 m2 will have the same NRKN population. The experiment was set up in a greenhouse set at 8 h dark and 16 h day diurnal cycle. Twelve weeks later, seedlings were assessed for presence or absence of NRKN by gall index. Based on the Ferris et al soil food web model, the rhizosphere and bulk soil in the muck soils were primarily disturbed and the mineral soils primarily degraded. Those of the non-agricultural soils of both soil types were disturbed. In three of the nine mineral soil fields and in all of the muck soils NRKN was present. How the presence of NRKN in degraded and disturbed soil health condition relates to parasitic variability is being investigated. Analysis of root-knot nematode resistance traits in carrot (Daucus carota) and cowpea (Vigna unguiculata) was conducted to determine presence of novel resistance genes and variation within and between root-knot nematode species for virulence to the resistance traits. In carrot, selections of entries were made from screenings of the USDA carrot germplasm collection exhibiting resistance to Meloidogyne incognita, M. javanica, and M. hapla.  High resistance was found in lines from Brasilia, South Africa and India to M. incognita and M. javanica. In the Brasilia source, QTL mapping using genotyping-by-sequencing derived SNPs revealed resistance determinant loci on carrot chromosomes 4 and 6. These results are being validated through analysis of additional segregating populations. Resistance to M. hapla in a carrot entry from Syria was found effective against nine out of ten different M. hapla isolates collected from different cropping systems and agro-ecologies. Segregation for resistance in a population developed from a heterozygous single root selection conformed to recessive inheritance behavior, and QTL mapping using genotyping-by-sequencing derived SNPs revealed a large-effect QTL on carrot chromosome 9. This result is being confirmed with a second mapping population. In cowpea, further analysis of the genome-level organization of root-knot nematode resistance traits revealed trait determinants on four of the 11 cowpea chromosomes. Single resistance traits were found for resistance to M. javanica and or M. incognita on chromosomes 1, 3 and 11. However, a complex resistance locus with allelic or tandem duplicated resistance specificities to virulent and avirulent M. incognita and M. javanica isolates, including one gene for resistance to root-galling, was found on cowpea chromosome 4. Fine mapping and candidate gene functional analysis using Agrobacterium rhizogenes-transformed hairy root cowpea plants is in progress to identify the specific coding genes underlying the resistance loci.     Objective 3:  Develop and assess nematode management strategies in agricultural production systems.  Plant-parasitic nematode the management can proceed down several paths. These paths include host plant resistance, chemical and biological controls with some strategies employing multiple approaches. A number of studies presented below have been performed to address objective 3. Included in such management plans is been a vineyard nematicide trial that has been performed due to the important agronomics of wine production. Wine distribution, sales, and consumption in New Mexico generates ~$876.7 million in annual economic activity. In 2017, the industry generated ~$51.6 million in state and local taxes, and $55.4 million in federal taxes. Nematodes can cause premature vineyard decline, reduced vine vigor, and increased fungal infection and virus transmission with yield losses of >60% due to nematodes (Teliz et al., 2007). Recent developments of new nematicides necessitate investigations into these new chemistries their integration with New Mexico cultural practices. A field study was conducted in 2018 to measure Meloidogyne incognita management and wine-grape plant response to three spring application rates (3.5, 5 and 7 pint per acre [pt/acre]) of fluensulfone (Nimitz®) compared to spirotetramat (Movento®) and an untreated control.  Treatments were applied to established (~ 20 years) non-grafted Cabernet Sauvignon grape (Vitis vinifera) vines with a history of severe root-knot nematode (M. incognita, RKN) injury under buried drip irrigation. Vines in some areas showed noticeable stunting and berry yield in the block being investigated was < 50% of that achieved prior to root-knot nematode symptom development. A number of observations have been made from the experiments including: (1) No phytotoxicity was observed from any of the three rates of Nimitz or from Movento 21 days after application; (2) Both the 3.5 and 7.0 pt/acre rates of Nimitz showed significant increases in general vine canopy vigor 21 days post-treatment; (3) Soil populations of RKN six weeks after spring treatments were significantly lower with 7.0 pt/acre Nimitz compared to the untreated control; (4) Six weeks after treatment applications, soil root-knot populations were significantly higher in plots treated with 5.0 pt/acre Nimitz compared to the 3.5 and 7.0 pt/acre rates and the untreated control.  This result is puzzling and unexplainable.  The trend persisted in population levels at harvest; (4) No significant reduction in root-knot nematodes occurred following fall application of 3.5 pt/A Nimitz to plots that received the same treatment in spring.  However, there was a large and significant increase in soil RKN numbers in plots previously treated with Movento; (5) Machine-harvested yields tended to be greater in plots treated with Nimitz and less in those treated with Movento compared to untreated plots; (6) Juice quality parameters were largely unaffected by any nematicide treatments in 2018. Work is being done to start tracking juice quality parameters to evaluate if there is a correlation between juice quality and RKN stress. The Movento treated plots had the highest RKN populations at the end of the season, the lowest yields, the highest juice sugar content, and decreased juice nitrogen values compared to those of other treatments. A pilot project was initiated in 2019 to focus on further evaluating this correlation. Data is currently being analyzed. A turfgrass nematicide trial is being conducted to evaluate the effects of several commercially available and experimental products on root-knot (Meloidogyne spp.) and ring (Mesocriconema nebraskense) soil nematode counts, visual turf quality, percent green cover, Dark Green Color Index (DGCI), Normalized Differences Vegetation Index (NDVI) and root development before and after treatment applications on Princess 77 bermudagrass (Cynodon dactylon) turf. We have finished the second year of the study and are currently analyzing data to summarize combined findings across both years. The experiments have been arranged as a randomized complete block design (RCBD) with six blocks. The treatments in this experiment include: (1) Non Treated Control; (2) Divanem (Abamectin) 0.28 oz/1,000ft2 (4 applications); (3) Nimitz Pro G (Fluensulfone) 1.38 oz/1,000ft2 (4 applications); (4) Indemnify (Fluopyram) 0. 3227 oz/1,000ft2 (2 applications); (5) Indemnify (Fluopyram) 0. 1963 oz/1,000ft2 (2 applications); (6) Indemnify (Fluopyram) 0.3227 oz/1,000ft2 (3 applications); (7) Todal (Abamectin) 1.31 oz/1,000ft2 (3 applications). Preliminary results from 2018 indicate that both high rate treatments of Indemnify (0.3227 oz/1,000ft2) with 2 and 3 application frequency, Todal and Divamen provided increased in-season control of Mesocriconema nebraskense. In-season control of Meloidogyne was present only with 2 applications of Indemnify at the high rate. Looking at carryover efficacy, plots previously treated with 3 applications of the high rate of Indemnify had lower presence of M. nebraskense and Meloidogyne sp. as grass emerged from dormancy the following spring. An analysis is being performed regarding winter Cover crop and nematode communities. The integration of winter cover crops (WCC) into an annual crop rotation has been shown in other environments to provide numerous soil ecological services, limit external input requirements and promote sustainability in many aspects of agriculture. In arid, irrigated systems, this practice may compete with irrigation demands of the cash crop and increase costs of farm operations through water availability and pumping costs as well as costs of labor. A study was initiated this year to address these issues. The objectives are to: (1) Determine the minimum water usage needed to produce a cover crop stand of adequate biomass to provide soil ecosystem benefits and (2) Assess impacts of irrigation regimes and cover crops on cash crop yields, soil quality indicators and soil pests. Data from these objectives will be used to select the cover crops and irrigation programs that are promising for ecosystem services while minimizing water use and farm operation costs. Three cover crops are being evaluated: Austrian winter pea (Pisum sativum subsp. sativum), barley, mustard (Sinapis alba X Brassica juncea var. Caliente 199), and a mix of all three. Five regimes of flood irrigation include: (1) a single fall irrigation after planting, (2) single fall and spring irrigations, (3) a single fall irrigation with two spring irrigations, (4) two irrigations in the fall and one in the spring and (5) two irrigations in both fall and spring. Plots have been arranged in a randomized complete block design, replicated four times, and each block is paired with a non-irrigated fallow check plot. This study is being conducted concurrently at Ag. Science Research Centers in southern and central New Mexico over two years, applying the same irrigation and cover crop treatments to the same plots each year. A cash crop of sweet corn (Zea mays) will be planted in all plots in both years. Biotic and abiotic response variables being measured to assess cover crop and irrigation impacts include: nematode community dynamics, weeds within cover crops, weed winter seedbank dynamics, soil suppressiveness to fungal disease (Verticillium dahliae and Phytophthora capsici), phospholipid fatty acid (PFLA) analysis of soil, permanganate oxidizable carbon, dry aggregate size distribution and wet aggregate stability, pH, electrical conductivity, macronutrients, micronutrients, organic matter and cation exchange capacity. The efficacy of new products in mint has been examined. Field, microplot, and greenhouse trials were conducted to determine chemical efficacy of several nematicide products against lesion, Northern root-knot (NRKN), and pin nematode on mint at the University of Idaho Research and Extension Center, Parma. The products tested, Velum Prime (fluopyram), Movento 240 SC (spirotetramat), and Vydate-L (oxamyl) showed moderate efficacy against lesion nematode over time, but little impact against NRKN or pin nematode. Additionally, two fungicidal products (Velum Prime, Elatus) were tested against Verticillium dahliae in greenhouse and field conditions. Neither was effective in managing verticillium wilt disease. The chemical efficacy of several new products against Southern RKN in greenhouse tomato have been examined. Greenhouse trials were developed to determine the efficacy of several new numbered products from Marrone Bio and Gowan for Southern root-knot nematode (SRKN) control in greenhouse tomato. The Marrone Bio product failed to provide significant control of SRKN, while the Gowan product reduced nematode counts in the soil and root tissue by significant margins- roughly a 50% reduction on average. Management strategies for Columbia RKN and lesion nematode in potato have been examined. Chemical efficacy of new non-fumigant chemistries and formulations, soil surfactant additives for fumigation, and several combinations of fumigants + non-fumigants were tested on potato in field conditions to determine management strategies for Columbia root-knot and lesion nematode. Fumigation of Telone II and Vapam HL proved extremely effective this year, reducing CRKN populations by 99% and reducing incidence of tuber infection to 3% or less despite high initial nematode populations. Non-fumigant nematicides did not fare as well against CRKN, showing no statistically significant differences in infected tuber counts from untreated controls. Treatments with Velum Prime and Vydate C-LV showed significant increases in yield when applied to lesion nematode-infested soil. Sugar beet cyst nematode management strategies in sugar beet have been examined. A green manure study and several chemical efficacy trials were conducted in field and greenhouse conditions to determine potential management of SBCN on beet yield and sugar production. Neither green manure treatments nor chemical treatments produced significant differences in sugar beet yields in field trials. Greenhouse chemical efficacy trials revealed two new numbered compounds from Gowan and Bayer that had significant impacts against SBCN. New nematode records have been made. The alfalfa cyst nematode Heterodera medicaginis was found in samples from Kansas, Montana, and Utah. This is the first time alfalfa cyst nematode has been found in North America. The cactus cyst nematode, Cactodera cacti, was found in Idaho and Colorado, a first for these two states. There has been a possible new turf Meloidogyne species or first report of M. marylandi occurring in New Mexico. Co-occurring in this study with Mesocriconema nebraskense, the Meloidogyne sp. present shares only a 92-93% identity to other isolates of M. graminicola (COII) (personal communication (Dr. Tom Powers-University of Nebraska). It is however, a 99% match to a turfgrass-Meloidogyne spp. recently found in Georgia that has been reported as M. marylandi. (G. B. Jagdale et al., Disease Notes [2019]). Dr. Paulo Vieira (Virginia Tech) has been further analyzing DNA sequences of our isolate and found it to share 99 to 100% identity on 18S+ITS and 28S D2/D3 with that of the isolate from Georgia but has only 93% identity and two to four gaps on COII-16S with many sequences of M. marylandi in GenBank. More isolates of M. marylandi are being evaluated for comparison. Physical cultures have been sent to Dr. Jon Eisenback (Virginia Tech) for morphological analysis. An unknown Rotylenchulus sp. has been recovered from the NMSU Leyendecker Plant Science Research Center, Las Cruces, NM with an affinity for corn. BLAST queries of the sequenced DNA (COII) indicate the isolate does not have a match in the GenBank database. It is not R. reniformis (86% match), R. parvus (87% match), or R. macrosoma (86% match) (personal communication, T. Powers-University of Nebraska). This unknown Rotylenchulus sp. has been isolated and is being grown in the greenhouse for morphological evaluation of all life stages. A turf project has been performed to evaluate the Unmanned Aerial Systems (UAS) for its ability to detect plant-parasitic nematode damage in turf grass through the Normalized Difference Vegetation Index (NDVI) and Normalized Difference Red Edge Index (NDRE) in conjunction with nematicide applications.  Both of the indexes used in this study are closely associated with plant health.  In 2018, microplot trials were conducted on ‘TifWay 419’ hybrid bermudagrass. Individual microplots had previously been inoculated with either Meloidogyne incognita or Belonolaimus longicaudatus. Nematicides included Multiguard Protect (furfural), Nimitz Pro G (fluensulfone), Divanem (abamectin), Indemnify (fluopyram), and an untreated control as a comparison.  Image analysis was collected via a DJI Phantom 4 equipped with a Micasense RedEdge-M camera at three time points: prior to nematicide treatment, 30 days after treatment (DAT), and 60 DAT.  Nematode population counts per 100 cm3 of soil were also taken the same time as image collection from each plot.  Data were analyzed using analysis of variance (SAS 9.4), and means were compared using the Dunnett’s statistic with P ≤ 0.05.  All nematicides led to a significant reduction of M. incognita at 30 DAT, and all but abamectin led to a significant reduction of B. longicaudatus at 30 DAT (P ≤ 0.05).  At 60 DAT, fluopyram was significantly lower than the untreated control in both nematode populations (P ≤ 0.05). Abamectin had a significantly lower M. incognita population compared to the untreated at 60 DAT (P ≤ 0.05). All other nematicides were statistically similar to the untreated at 60 DAT (P ≤ 0.05).  All treatments except furfural saw a significant increase in NDVI and NDRE values compared to the untreated control at 30 DAT, indicating an increase in plant vigor (P ≤ 0.05). At 60 DAT, only fluopyram had a significantly higher NDVI value compared to the untreated, and NDRE values were statistically similar across all treatments. Overall, all nematicides were effective at lowering both M. incognita and B. longicaudatus populations, and positive trends were observed for both NDVI and NDRE indexes for plant health analysis. This data shows that NDVI and NDRE can be valuable vigor assessments for tracking nematode populations in turfgrass. The interactions between the RKN and fusarium (Fusarium oxysporum) have been investigated. The overall objective of the study was to evaluate the presence of FOV races in a cotton (Gossypium sp.) field and document the effects of M. incognita population density and resistance traits of the cotton.  A total of 132 isolates of FOV were collected throughout the season which represented 7 different races.  The most prominent race of FOV collected from the field was race 1, a race known to have a strong interaction with M. incognita. The highest nematode population density was recorded on the two Pima cotton varieties included in the test, Phytogen 800 and Pima S7 (2069 and 1539 eggs/g of root respectively). However, low rates of FOV infection, 8% on Phytogen 800 and 4% on Pima S7, were recorded on these varieties which may be due to resistance traits to FOV that are possessed by these varieties.  The highest infection rate of FOV (16%) was recorded on Rowden variety of upland cotton which also supported the highest M. incognita population density (316 eggs/g of root) of any upland cotton varieties.  A similar rate of FOV infection (14%) was recorded on the upland cotton variety of DP 1558NR B2XF.  This is a M. incognita resistant cotton variety that supported low population density of nematodes; however, the variety is also susceptible to FOV. This result demonstrates that nematode resistance alone is not sufficient to protect against FOV. It is well known that Rotylenchulus reniformis causes yield loss in cotton across the mid-south and southeastern region. Further experiments have been performed with the objective being to quantify the yield loss due to R. reniformis and document any yield increase from the addition of a nematicide. Field trials were established in two adjacent fields, one was infested with R. reniformis and one where R. reniformis was not detected. In both fields, seven cotton cultivars were planted with and without Velum Total (1.02 L/ha). In 2017, R. reniformis reduced cultivar yields by an average of 59% between the non-infested and the R. reniformis infested field. The nematicide application increased seed cotton yields in the R. reniformis field by 55% and no yield increase was observed in the non-infested field. In 2018, R. reniformis reduced seed cotton yields by an average of 42% between the non-infested field and the R. reniformis infested field. Across the cultivars addition of the nematicide increased seed cotton yields by an average of 6% in the R. reniformis infested field and an average of 8% in the non-infested field. The nematicide reduced R. reniformis eggs per gram of root by an average of 92% in 2017 and 78% in 2018 across all cotton cultivars.  Overall R. reniformis reduced seed cotton yields by 50% which was equivalent to 2,225 kg/ha.    Plants recognize nematode infections during root penetration, before initiating an elaborate feeding site characteristic of sedentary endoparasitic nematodes, and initiating a strong immune response. This immune response, known as pattern-triggered immunity, is tightly regulated. Tight regulation is necessary to control runaway immunity that may cause uncontrolled cell death or autoimmune disease. Such controls, also known as negative regulators of immunity, have been identified in Arabidopsis thaliana, orthologs are which are also present in crops including tomato. The absence of one such negative regulators results in enhanced resistance to the root-knot nematode, Meloidogyne incognita, in A. thaliana. To develop a similar resistance in tomato, tomato orthologs of the A. thaliana gene were targeted for mutations using clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 gene editing. CRISPR-Cas9 vectors used for editing tomato were used to develop constructs to edit two different tomato homologs of the negative regulator of immunity. Constructs targeting the individual genes or both genes together, using two guide RNAs for each, were developed and used in Agrobacterium/Rhizobium rhizogenes transformation of tomato cotyledons. Hairy roots induced by A. rhizogenes transformation were evaluated for deletions in the targeted genes using PCR. Our results indicated high efficiency in deletion in one of the targeted genes and lower efficiency in the second gene. No transgenic roots were identified with deletions in both genes suggesting either low mutation efficiency or lethal phenotype when both genes are eliminated. The successful constructs are currently being used to develop stable transgenic gene edited tomato plants for evaluation with nematodes. Plants have an intrinsic ability to protect themselves from parasitic nematodes. However, processes relating to the nematode circumvent these defense processes. To examine if it is possible to activate these intrinsic plant defense processes in a normally susceptible host, laser microdissection has been done on Glycine max (soybean) root cells prior to and after parasitism by H. glycines. Hundreds of genes have been determined to be expressed specifically within the cells that are parasitized by H. glycines, but are undergoing a defense response. Prior work has shown the bacterial effector harpin effectively decreases parasitism by M. incognita, R. reniformis and H. glycines. Harpin treatment results in the activated transcription of a membrane receptor called NON-RACE SPECIFIC DISEASE RESISTANCE 1 (NDR1) which functions in defense to plant parasitic nematodes. NDR1 has been shown in new experiments to activate mitogen activated protein kinase (MAPK) signaling in the G. max-H. glycines pathosystem that leads to a defense response. In G. max there are 32 MAPKs. Transgenic experiments show that 9 of the 32 MAPKs function in defense. Illumina® RNA sequencing of the 9 MAPK overexpressing and also the 9 MAPK suppressing (by RNA interference [RNAi]) transgenic lines have led to the identification of over 450 candidate defense genes. Experiments are being performed to determine what role they perform in resistance to H. glycines. More broadly, many of these genes are highly conserved between different taxonomic groups of plants so it is likely that the types of genes identified in the G. max-H. glycines pathosystem will be relevant to the discovery of defense genes in other agriculturally relevant crops species.     Impact Statements <ul> <li>Novel plant receptors involved in recognition and response to nematode infection have been identified.</li> <li>Continued efforts are being made to refine and define the conditions and limitations DNA barcoding using the COI mitochondrial gene.</li> <li>Barcoding surveys on a large geographic scale will help establish species boundaries of plant parasitic nematodes.</li> <li>A field device for rapid identification of cyst nematode juveniles could accelerate the time and reduce the expense of species identification.</li> <li>Global assessments of nematode abundance and community trophic structure will aid in monitoring below ground changes due to environmental conditions.</li> <li>Mixing the soil with a spader tiller after shank injection of metam sodium did not improve control of tuber damage from Columbia root-knot nematode (Meloidogyne chitwoodi).</li> <li>A new oxamyl product, ReTurn XL, was equal to Vydate C-LV at suppressing tuber damage from CRKN.</li> <li>Using Velum Prime (Fluopyram) in-furrow was as good as using Vydate in-furrow.</li> <li>No treatments were effective if they did not have either Vydate or Velum Prime in-furrow.</li> <li>Replacing two mid-season Vydate applications with Movento (Spirotetramat) did not reduce the level of control.</li> <li>preplant incorporated (PPI) application of Nimitz (Fluensulfone).alone had no effect on the level of culled tubers but appeared to be of benefit when used before a full season program consisting of an in-furrow application of Velum Prime (or presumably Vydate) and the complete in-season Vydate program.</li> <li>There are several reasons to use Velum Prime in-furrow rather the oxamy1: (a) Velum Prime is less toxic than oxamyl so growers may be more inclined to use it in-furrow, (b) Velum Prime may be marginally better than oxamyl, (c) Allows one or two more in-season applications of oxamyl before the allowable a.i. is reached</li> <li>Overall, our molecular studies on resistance in potato combined with our work on the genetic variability of different chitwoodi races has given us insights into the genetic factors involved in plant-nematode interactions.</li> <li>The experiments establish a basis for identifying the biotic and abiotic factors of nematode adaptation and parasitic variability that lead to understanding biological interactions and developing location-specific solutions.</li> <li>The experiments develops new knowledge on natural host resistance traits to manage root-knot nematodes in field and vegetable crops, which can be adopted by plant breeding programs and the seed industry to benefit growers by producing nematode resistant crop varieties.</li> <li>Normalized Differences Vegetation Index (NDVI) and Normalized Difference Red Edge Index (NDRE) can be valuable vigor assessments for tracking nematode populations in turf.</li> <li>Root knot nematode resistance in cotton will not eliminate FOV disease incidence.</li> <li>The reniform nematode reduced cotton yield potential in half even with nematicide applications.</li> <li>Growers plant healthy fields first and wash equipment after leaving a nematode infested field.</li> <li>Understanding how plant immunity is regulated to resist nematode infection will lead to better engineering crops with broad-spectrum and durable resistance.</li> <li>Understanding the genetic basis of resistance in one plant can be used as an effective tool for identifying the underlying conserved mechanism of resistance in other important crop species.</li> </ul>

Publications

Publications Acar I, Sipes S. 2019. Enhancing the biological control potential of entomopathogenic nematodes protection from desiccation and UV radiation. Biological Control (Submitted). Alshehri HA, Alkharouf NW, Darwish O, McNeece BT, Klink VP. 2019. MAPKDB: A MAP kinase database for signal transduction element identification. Bioinformation 15:338-341. DOI: 10.6026/97320630015338. Austin HW, McNeece BT, Sharma K, Niraula PM, Lawrence KS, Klink VP. 2019. An expanded role of the SNARE-containing regulon as it relates to the defense process that Glycine max has to Heterodera glycines. Journal of Plant Interactions 14:276-283. DOI: 10.1080/17429145.2019.1622043. Disi JO, Mohammad HK, Lawrence K, Kloepper J, Fadamiro H. 2019. A soil bacterium can shape belowground interactions between maize, herbivores and entomopathogenic nematodes. Plant Soil 437:83–92.  DOI.org/10.1007/s11104-019-03957-7. Eisenback JD, Holland LA, Schroeder, J, Thomas S, Beacham JM, Hanson SF, Paes-Takahashi VS, Vieira P.  2019.  Meloidogyne aegracyperi n. sp. (Nematoda: Meloidogynidae), a root-knot nematode parasitizing yellow and purple nutsedge in New Mexico.  Journal of Nematology 51: DOI: 10.21307/jofnem-2019-071. Groover W, Lawrence KS, Donald P. 2019. Reproductive rate differences of root-knot nematodes from multiple crops in a single field. Nematropica 49:00-00 (In press). Hall, M. Lawrence KS, Shannon DA, Gonzalez T, Newman M. 2019. Southern root knot nematode (Meloidogyne incognita Kofoid and White) Chitwood susceptibility to tumeric (Curcuma longa L.) accessions. International Journal of Applied Research on Medicinal Plants 2:007. DOI:10.29011/IJARMP-107.100007. Lonardi S, Muñoz-Amatriaín M, Liang Q, Shu S, Wanamaker SI, Lo S, Tanskanen J, Schulman AH, Zhu T, Luo M-C, Alhakami H, Ounit R, Hasan AM, Verdier J, Roberts PA, Santos JRP, Ndeve A, Doležel J, Vrána J, Hokin SA, Farmer AD, Cannon SB, Close TJ. 2019. The genome of cowpea (Vigna unguiculata [L.] Walp.). The Plant Journal 98:767–782. DOI: 10.1111/tpj.14349. Marquez J, Sipes B, Cheng Z, Wang K-H. 2019. Enhancement of indigenous entomophathogenic nematodes by no-till cover cropping with black oat (Avena strigose) in a corn (Zea mays) agroecosystem. Biological Control (Submitted). McNeece BT, Sharma K, Lawrence KS, Lawrence GW, Klink VP. 2019. The mitogen activated protein kinase (MAPK) gene family functions as a cohort during the Glycine max defense response to Heterodera glycines. Plant Physiology and Biochemistry 137:25–41. DOI.org/10.1016/j.plaphy.2019.01.018. Ndeve AD, Santos JRP, Matthews WC, Huynh BL, Guo Y-N, Lo S, Muñoz-Amatriaín M, Roberts PA. 2019. A novel root-knot nematode resistance QTL on chromosome Vu01 in cowpea. G3 (Genes, Genomes, Genetics) 9:1-11. DOI: 10.1534/g3.118.200881. Ozbayrak M, Todd T, Harris T, Higgins R, Powers K, Mullin P, Sutton L, Powers T. A COI DNA barcoding survey of Pratylenchus species in the Great Plains region of North America. Journal of Nematology.  51:e2019-81. DOI: 10.21307/jofnem-2019-081. Powers T, Skantar A, Harris T, Higgins R, Mullin P, Hafez S, Handoo Z, Todd T, Powers K. 2019. DNA barcoding evidence for the North American presence of alfalfa cyst nematode, Heterodera medicaginis. Journal of Nematology 51:1–17. DOI: <a href="https://doi.org/10.21307/jofnem-2019-016">https://doi.org/10.21307</a>. Skantar AM, Handoo ZA, Kantor MR, Hult MN, Hafez SA. 2019. First report of the cactus cyst nematode, Cactodera cacti from a cactus garden in Idaho. Journal of Nematology 51:1-6. DOI: <a href="https://doi.org/10.21307/jofnem-2019-044">https://doi.org/10.21307/jofnem-2019-044</a>. Van Den Hoogen, J, Geisen, S, Routh D, Ferris H, Traunspurger W, Wardle DA, De Goede RGM, et al. 2019. Soil nematode abundance and functional group composition at a global scale. Nature 572:194-198. DOI: 10.1038/s41586-019-1418-6. Zasada IA, Ingham RE, Baker H, Phillips WS. 2019. Impact of Globodera ellingtonae on yield of potato (Solanum tuberosum). Journal of Nematology. 51:2019-073. <a href="https://doi.org/10.21307/jofnem-2019-073">https://doi.org/10.21307/jofnem-2019-073</a>. Zasada IA, Kitner M, Wram C, Wade N, Ingham RE, Hafez S, Mojtahedi H, Chavoshi C, Hammack N. 2019. Trends in occurrence, distribution, and population densities of plant-parasitic nematodes in the Pacific Northwest of the United States from 2012 to 2016. Plant Health Progress. 20:20-28. <a href="https://doi.org/10.1094/PHP-11-18-0077-RS">https://doi.org/10.1094/PHP-11-18-0077-RS</a>.     Abstracts, Proceedings, Conferences and Reviews Brown JK, Avelar S, Schrimsher DW, Conner K, Jacobson A, Lawrence K. 2019. Identification of a Cotton Leafroll Dwarf Virus- Like polerovirus infecting cotton in Alabama during 2017-2018. Proceedings of the 2019 Beltwide Cotton Conference 1:40-46. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm</a>. Dyer D, Lawrence KS. 2019. Effect of Meloidogyne incognita populations density on the prevalence of Fusarium oxysporum f. sp. vasinfectum races. Journal of Nematology 51: (In press). Dyer D, Lawrence KS. 2019. Use of a Liquid Fertilizer (AgraLi) to Reduce Rotylenchulus Reniformis Population Density and Increase Cotton Yields. Proceedings of the 2019 Beltwide Cotton Conference 1:363. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm</a>. Dyer DR, Lawrence K, Aida M. 2019. Evaluations of the temporal and spatial occurrence of Fusarium oxysporum f. sp. vasinfectum races as influenced by selected cotton genotypes in the National Cotton Fusarium Wilt evaluation field in Alabama. Proceedings of the 2019 Beltwide Cotton Conference 1:364-371. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm</a>. Faske TR, Allen TW, Grabau Z, Kemerait R, Lawrence KS, Mehl HL, Overstreet C, Thiessen LD, Wheeler TA. 2019. Beltwide Nematode Research and Education Committee Report on Field Performance of Seed-Applied and Soil-Applied Nematicides, 2018. Proceedings of the 2019 Beltwide Cotton Conference 1:364-371. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm</a>. Gattoni K, Xaing N, Lawaju BR, Lawrence KS, Kloepper JW. 2019. Systemic response stimulated by Bacillus spp. can manage Meloidogyne incognita population density in Gossypium hirsutum. Proceedings of the 2019 Beltwide Cotton Conference 1:114-122. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm</a>. Gattoni K, Xiang N, Lawaju B, Lawrence KS, Park SW, Kloepper JW. 2019. Potential mechanism of action for Bacillus spp. inducing resistance to Meloidogyne incognita on cotton. Journal of Nematology 51: (In press). Giese WG, Beacham JM, Velasco-Cruz C, Thomas SH, Powers TO. 2019.  Nematode occurrence, frequency, relationships and correlations in New Mexico vineyards. Journal of Nematology 51: (In press). Groover W, Lawrence KS, Dyer D. 2019. Yield loss of cotton cultivars due to the reniform nematode and the added benefit of Velum Total. Proceedings of the 2019 Beltwide Cotton Conference 1:333-336. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm</a>. Groover W, Lawrence KS. 2019. Unmanned aerial system imagery analysis of modern turf grass nematicides. Journal of Nematology 51: (In press). Guyer RR,  Newman MS, Kelly H, Allen TW, Sciumbato G, Wilkerson TH, Barham JD, Barnett W, Beach A, Keiser AR, Bayles MB, Verhalen LM, Caceres J, Lawrence GW, Colyer PD, Kelley T, Thacker R, Kemerait RC, Lawrence KS, Mehl HL, Phipps PM, Padgett G, Price P, Rothrock C, Winters S, Schuster G, Spurlock T, Woodward J. 2019. A historical review of the national cottonseed treatment program: 1995-2017. Proceedings of the 2019 Beltwide Cotton Conference 1:587-591. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm</a>. Heather K, Guyer RR, Pate SN, Allen TN, Wilkerson TH, Bayles MB, Colyer PD, Lawrence KS, Mehl H, Price P, Spurlock T, Woodward J, Cartwright ML. 2019. Report of the Cottonseed Treatment Committee for 2018. Proceedings of the 2019 Beltwide Cotton Conference 1:577-584. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm</a>. Kaloshian I, Teixeira M. 2019. Advances in plant−nematode interactions with emphasis on the notorious nematode genus Meloidogyne. Phytopathology 109:1988-1996. DOI: 10.1094/PHYTO-05-19-0163-IA. Klink VP. 2019. A developmental genomics analysis of soybean defense processes. Plant and Animal Genomes Meeting XXVII. San Diego, CA. Klink VP. 2019. The use of crop functional developmental genomics to enhance undergraduate education. 83rd Mississippi Academy of Sciences Annual Meeting-Science Education Section, Hattiesburg, MS. Klink VP, McNeece BT, Sharma K, Niraula P, Troell HA, Khatri R, Adhikari M, Acharya S. 2019. A functional genomics analysis of 20 S particle proteins in Glycine max as it resists infection by the plant parasitic nematode Heterodera glycines. American Society of Cell Biologists. Washington DC. Lartey I, Marsh TL, Melakeberhan H. 2019. Soil type-driven foodweb dynamics associated Meloidogyne hapla in Michigan vegetable fields. Society of Nematologists 58th Annual Meeting. Raleigh, NC. 57. Lawrence KS, Jacobson A, Sikora E, Hagan A, Conner K, Schrimsher D, Brown JK. 2019. Cotton Leafroll Dwarf Virus – A Polerovirus identification, symptomatology, and occurance in Alabama. Proceedings of the 2019 Beltwide Cotton Conference 1:125-128. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm</a>. Lawrence KS, Sandlin T, Raper TB, Butler S, Kelly H, Meyer B, Silvey N. 2019. Cotton cultivar disease incidence, severity, and yields when challenged with Verticillium Wilt in the Tennessee Valley Region, 2018. Proceedings of the 2019 Beltwide Cotton Conference 1:129-132. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm</a>. Lawrence KS, Hagan A, Norton R, Hu J, Faske TR, Hutmacher RB, Mueller J, Small I, Grabau ZJ, Kemerait RC, Price P, Allen TW, Atwell S, Idowu J, Thiessen LD, Byrd SA, Goodson J, Kelly H, Wheeler T, Isakeit T Mehl HL. 2019. Cotton Disease Loss Estimate Committee Report, 2018. Proceedings of the 2019 Beltwide Cotton Conference 1:54-56. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm</a>. Luff K, Hafez SL.  2019. The use of new chemistries for potato nematode management programs in Idaho, USA. Society of Nematology, South Carolina. Nunes MN, Lawaju B, Groover W, Dyer D,  Gattoni K, Sanchez W, Lawrence KS. 2019. Nematicide application through drip irrigation systems for Southern Root-knot nematode management. Journal of Nematology 51: (In press). Park, SW, Liu W, Jones AL, Gosse HN, Lawrence KS. 2019. Root exudates convey host-specific messages that control the short-range underground orientation of plant parasitic nematodes. Journal of Nematology 51: (In press). Pate SN, Kelly H, Guyer RR, Lawrence KS, Allen TW, Bayles MB, Colyer PD, Mehl H, Price P, Spurlock T, Woodward J. 2019. Current methods of the national cottonseed treatment program and proposed changes in protocol.  Proceedings of the 2019 Beltwide Cotton Conference 1:548-551. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm</a>. Rondon MN. Lawaju BR, Lawrence KS. 2019. In vitro effect of fungicides on Corynespora cassiicola isolates from cotton and soybean in Alabama. Proceedings of the 2019 Beltwide Cotton Conference 1:151-156. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2019/index.htm</a>. Sanchez, WD, Williams G, Lawrence KS. 2019. Efficacy of entomopathogenic nematodes on small hive beetles (Aethina tumida) in kalmia loamy sand. Journal of Nematology 51: (In press). Zhang L, Gleason C, 2019. Bacterially secreted defense peptide StPep1 stimulates root-knot nematode resistance in potato. The XVII Congress on Molecular Plant-Microbe Interactions, Glasgow, Scotland. Zhang L, Gleason C, 2019. Engineering bacteria as delivery agents of the defense-inducing peptide StPep1 improves root-knot nematode resistance in potato. Society of Nematologists 58th Annual Meeting. Raleigh, NC.

Impact Statements

Date of Annual Report: 01/11/2021

Report Information

Annual Meeting Dates: 11/12/2020 - 11/13/2020
Period the Report Covers: 01/01/1970 - 01/01/1970

Participants

Gleason, Cynthia (Washington State University)
Hafez, Saad (University of Idaho)
Ingham, Russell (Oregon State University)
Kaloshian, Isgouhi (University of California-Riverside)
Klink, Vince (Mississippi State University)
Lawrence, Kathy (Auburn University)
Melakeberhan, Haddish (Michigan State University)
Powers, Tom (University of Nebraska)
Roberts, Phil (University of California-Riverside)
Siddique, Shahid (University of California-Davis)
Sipes, Brent (University of Hawaii)

Guests: A. Borgmeier, A. Coomer, A. Sales, S. Szumski, V. Williamson, H. Yimer

Brief Summary of Minutes

Kaloshian reported on effector-triggered immunity. S. Siddique shared results of research on PSY peptides. V. Klink related work on the early defense processes with xyloglucans. K. Lawrence reported on resistance and nematicides for nematode control. S. Hafez relayed identification of sever first reports of nematodes in Utah, and California. R. Ingham shared results of test with the harpin protein for nematode control. P. Roberts discussed allelic dosage and additive effects of resistance against nematodes. A. Borgmeier highlighted nematode diversity in a prairie corridor. H. Melakeberhan presented results of soil health and nematode adaptations to environments. C. Gleason discussed work on induced resistance, immune-stimulants, and diagnostics. B. Sipes share work on improvement of entomopathogenic nematode living bombs and nematicides.Loper shared that these are different times and thanked the project on their efforts, noting this is a broad project with aspect from molecular to the field. The 2020 report had particularly good impact statements. It would be good to feature collaborative efforts in this year’s report such as between Washingtion, Wisconsin and USDA; Idaho and Nebraska; Michigan and Hawaii; and Alabama and Mississippi. NIFA Kansas City is 95% staffed with two new Multistate Program Leaders.Fayad has been assigned as MPL to our project and wanted to reiterate J. Loper’s comments.

Business

Officer Election: C. Gleason will rotate from Vice Chair to Chair. K Lawrence will rotate from Secretary to Vice Chair. S. Siddique was elected Secretary by acclamation.

2021 Meeting Site: Hawaii will host the meeting assuming pandemic restrictions are not prohibitive. Davis, California will serve as the backup site if issues arise with travel to Hawaii.

Accomplishments

Objective 1:   Characterize genetic and biological variation in nematodes relevant to crop production and trade.  Plant-parasitic nematodes are a large diverse group of nematodes that cause significant agricultural loses globally.  In economic terms, annual crop losses due to plant-parasitic nematodes are estimated to be least $8 billion in the United States and $80 billion worldwide. Due to their significant, detrimental effects in agricultural systems, it is critical that scientists study nematode species associated with crop production and trade, and in doing so, investigate the genetic and biological variation within a nematode species. Intraspecies variation can significantly impact nematode management strategies. With this in mind, the following activities have been performed regarding objective 1. Researchers at the University of California at Riverside (UCR) have conducted an analysis of root-knot nematode resistance traits in carrot and cowpea to determine presence of novel resistance genes and variation within and between root-knot nematode species for virulence to the resistance traits. In carrot, high resistance was found in carrot lines from Brasilia, South Africa and India to Meloidogyne incognita and M. javanica. Resistance to M. hapla in a carrot entry from Syria was found effective against nine out of ten different M. hapla isolates collected from different cropping systems and agro-ecologies. In cowpea, analysis was continued of the genome-level organization of root-knot nematode resistance traits, identified on four of the 11 cowpea chromosomes. Researchers have established an Agrobacterium rhizogenes-transformed hairy root system for cowpea plants to study resistance traits. Several researchers in the project work on potato-nematode interactions.  Potatoes rank as one of the four most important staple crops on a global scale, and Washington/Oregon/Idaho produce a significant portion of the potatoes grown in the USA. Meloidogyne chitwoodi (also known as the Columbia root-knot nematode) is major problem for potato producers in this region. The nematode infects the potatoes and causes tuber defects that can significantly diminish the value of the crop. The different pathotypes of M. chitwoodi have been an on-going issue. Researchers at Washington State University have performed genomic and transcriptomic analyzes of different races/pathotypes of M. chitwoodi. This has led to insights into its intraspecies genetic diversity. Additional molecular diagnostic tools for M. chitwoodi and other potato-infecting root-knot nematodes are being developed.  Using information about nematode variability has also been important for cyst nematode diagnostic assays. Together with a Nebraska based biotechnology MatMaCorp, researchers at University of Nebraska are continuing to validate a 4-cyst nematode diagnostic assay for single J2s in the soil. The assay features simultaneous identification of four different Heterodera species known from the Great Plains regions. The assay uses a rolling-circle style amplification that produces a detectable signal within an hour and can be performed in the field. Its performance in community DNA soil extractions is currently being tested.  Cyst and root-knot nematodes are the most economically important plant parasitic nematodes in the USA. Researchers at Michigan State University have focused on both the soybean cyst nematode (SCN) and the Northern root-knot nematode (NRKN). Research has looked at SCN adaptation by simulating Midwest cropping systems and changes in soil conditions over time. After almost two decades after SCN was introduced, the research into the effects of tillage, rotation and crop species (e.g. till or no-till and corn (C), SCN-resistant (R), SCN-susceptible (S) monocropping or RCRC, SCSC rotation) shows that SCN is barely detectable and less so in no-till than in tilled plots. The focus on NRKN started with characterizing its distribution in soil types across regions and testing parasitic variability (PV) of populations isolated from the field under greenhouse conditions. About half a dozen NRKN populations are being characterized for PV by assessing their ability to induce galling in a series of experiments. The data provide insights into how nematodes establish and adapt in new locations.   Objective 2:  Determine nematode adaptation processes to hosts, agro-ecosystems and environments.  A number of actions have been performed under objective 2 (studying nematode adaptation to climatic conditions, cropping systems, and/or soil properties).  For example, work at Michigan State University has focused on understanding the distribution, parasitic variability (PV) and adaptation of soybean cyst (SCN) and northern root-knot nematodes (NKRN) in Michigan cropping systems. The goal has been to understand how SCN and NRKN PV relate to the biological and physiochemical conditions in the environment in which they survive. Studies have been undertaken to understand how SCN adaptation relates to changes in soil biophysiochemical conditions. Cropping systems seem to have the greatest influence on the soil food web. Now soil microbiomes have been incorporated into the soil analysis. Investigations are continuing in order to study how changes in soil microbiomes relate to soil health and potential SCN adaptation. Meanwhile, NRKN PV seems to be associated with soil types, but its occurrence relative to soil health conditions remains unknown. Preliminary analyses suggest that soils in which NKRN has been observed seem to have degraded and depleted soil food web conditions. This work lays down a foundation for more targeted investigations to understand the potential links between NKRN’s PV and ecosystem to microbiome level changes in its soil environment.  Another project in objective 2 has been to study nematode adaptation, at the community level, in different geographic locations. At the University of Nebraska, researchers are examining changes in the soil nematode community within native and unplowed grazing lands that feature varying levels of disturbance and management regimes. By using DNA barcoding, the project has looked at the biodiversity of nematode communities. This data will be important for gaining an understanding of the prairie ecosystem and how the nematode communities in one prairie space compare to communities form other prairie spaces in the Midwest.  Lastly, within in this objective, new nematode records have been made. There was a first report of Ditylenchus dipsaci from alfalfa in New Mexico. New Mexico alfalfa hay production ranked as the fourth largest cash commodity in the state $125 million with 160,000 planted. It is a critical agricultural industry that supports the dairy and cattle producing industries, which are the two top yielding agricultural commodities in New Mexico.The alfalfa cyst nematode Heterodera medicaginis was found in samples from Kansas, Montana, and Utah. This is the first time that the alfalfa cyst nematode has been found in North America. The cactus cyst nematode, Cactodera cacti, was found in Idaho and Colorado, a first for these two states. There was a first report of Cactodera milleri from Quinoa fields in Colorado.  Objective 3:  Develop and assess nematode management strategies in agricultural production systems.            There are many approaches for controlling plant parasitic nematodes in agriculture. Although chemical nematicides are often used, research is needed to investigate new formulations or application methods. Other approaches to nematode control include host plant resistance, green manures, and biological controls. Overall, there is a continued need for new safe, effective and inexpensive nematode control options. A number of studies presented below have been performed to address objective 3, the development and assessment of nematode management strategies. Conventional potato growers primarily rely on nematicides to control root-knot nematodes on potato. Several trials were conducted at Oregon State University to test new management strategies using nematicides to control tuber damage from Meloidogyne chitwoodi. After harvest, tubers were peeled and examined for M. chitwoodi infection. Any tuber with six or more infection sites was considered a cull. Employ (Plant Health Care, Inc., Raleigh, NC) contains 1% Harpinαβ, a protein that is said to activate a natural defense mechanism in host plants referred to as systemic acquired resistance (SAR). Various applications (seed piece dipping, foliar treatments) were made at planting or after plant emergence  to plants that had been inoculated with M. chitwoodi eggs. None of the treatments had any effect on the number of J2 or eggs recovered. Work on nematicides at the University of Idaho looked at the efficacy of new non-fumigant chemistries and formulations and several combinations of fumigants + non-fumigants  on potato fields to determine management strategies for Pratylenchus species and Meloidogyne chitwoodi. Treatments with Velum Prime and Vydate C-LV have showed significant increase in yield when applied to lesion nematode-infested soil.  Efforts to move away from nematicide use in potato have also been undertaken. In one project in this objective, potato roots were treated with the defense elicitor peptide called Pep1. Treatment with a plant peptide enhanced potato resistance against Meloidogyne chitwoodi. To develop an easy method to deliver this peptide to potato, researchers at Washington State University engineered the bacteria Bacillus subtilis to produce and secrete Pep1. By treating the potato plants with B. subtilis that secretes the Pep1 defense elicitor, the plants became more resistant against M. chitwoodi. This indicates that a “probiotic” bacterial treatment of potatoes may help growers combat M. chitwoodi. An alternative to method of nematode control in potato is to use cover crops. Several cover crops are being marketed in the Pacific Northwest to be grown as green manure crops to suppress nematodes and soil borne fungal diseases. One important factor for success is for the crop grown prior to incorporation to be a poor or non-host for Columbia root-knot nematode (CRKN, Meloidogyne chitwoodi). The host status of most of these crops is not currently known. In a trial performed by Oregon State University researchers, three-week-old seedlings were inoculated with 5,000 CRKN eggs. Plants were harvested 55 days later, eggs were extracted from roots, and the Reproductive factor (Rf = final population/initial population) was determined. Good hosts were determined as plants with an Rf of 1.00 or greater, poor hosts as those with an Rf from 0.01 to 1.00 and non-hosts as those with an Rf less than 0.01. Caliente 199, Caliente Rojo, Caliente 61 and Trifecta Power Blend were determined to be good hosts and were not different from wheat (the good host standard). Caliente 119, Kodiak, Pacific Gold, White Gold and a blend of Nemat and Caliente 61 were good hosts but had Rf values less than wheat. Nemat alone and in blends with Caliente 199 or Caliente Rojo were poor hosts while Terranova and Sordan 79 were non-hosts. This data will help growers chose the best cover crops for CRKN control. In addition to infecting potato, plant-parasitic nematodes are also a major pest of turfgrass in the United States, yet there are few options for successful management. Most current management strategies rely on the use of a limited number of chemical nematicides, so finding a new management option for nematode suppression would be extremely valuable for turfgrass managers. The goal of this study at Auburn University was to evaluate a new nematicide, fluazaindolizine (Reklemel™ active), for its ability to reduce plant-parasitic nematode population density and improve turfgrass quality. Greenhouse evaluations performed at demonstrated multiple rates of fluazaindolizine reduced B. longicaudatus population density, and one of the two M. incognita trials showed multiple rates of fluazaindolizine reduced nematode population density. Reklemel was also effective at reducing population density of both B. longicaudatus and M. incognita in microplot settings for both 2018 and 2019, and a significant improvement in turf quality was observed for both visual turfgrass ratings and NDVI. Field trials demonstrated a significant reduction for both B. longicaudatus and M. incognita population density by multiple rates of fluazaindolizine, but no significant differences in turf quality ratings were observed. Overall, fluazaindolizine shows promise as a chemical nematicide for plant-parasitic nematode management on turfgrass.         Cotton can also be infected by nematodes, and researchers at Auburn University have studied Fusarium oxysporum f. sp. vasinfectum (FOV) and Meloidogyne incognita infections on cotton. FOV and M. incognita combine to form the Fusarium wilt disease complex of cotton, which has been causing losses in the cotton industry around the world for more than 125 years. The goal of this study was to evaluate the use of fluazaindolizine (Reklemel™ active), for its ability to lower M. incognita population density, its effects on FOV, and its usefulness in management the FOV-nematode disease complex. The objectives of this study were 1) evaluate the impact of ReklemelTM on the growth of FOV isolates in vitro and 2) assess cotton growth, yield, and disease incidence with the application of ReklemelTM under greenhouse and field conditions. In greenhouse testing, ReklemelTM significantly reduced M. incognita population density but had no significant effect on Fusarium wilt incidence. However, in the field, ReklemelTM reduced both M. incognita population density and Fusarium wilt incidence. This reduction in FOV incidence was not observed with the treatment of Velum TotalTM which had statistically similar reductions in M. incognita egg population density. Rotylenchulus reniformis another important nematode that causes yield loss in cotton across the mid-south and southeastern region. Researchers at Auburn University wanted to quantify the yield loss due to Rotylenchulus reniformis and document any yield increase from the addition of a nematicide. Field trials were established in two adjacent fields, one was infested with R. reniformis and one where R. reniformis was not detected. In both fields, seven cotton cultivars were planted with and without Velum Total (1.02 L/ha). Across the cultivars, addition of the nematicide increased seed cotton yields by an average of 6% in the R. reniformis infested field and an average of 8% in the non-infested field. The nematicide reduced R. reniformis eggs per gram of root by an average of 92% in 2017 and 78% in 2018 across all cotton cultivars.  Research on new nematicides has also been performed in mint fields. Several plant parasitic nematodes infect mint, and researchers at the University of Idaho, Parma research and extension center worked to determine the efficacy of new chemical compounds against Pratylenchus sp., Meloidogyne hapla and Paratylenchus species infecting mint. Results from some of the products tested [Velum Prime (fluopyram), Movento 240 SC (spirotetramat), and Vydate-L (oxamyl)] showed moderate efficacy against lesion nematode over time, but little impact against NRKN or pin nematodes. In addition to the mint trials, work in Idaho also looked at nematicides on greenhouse tomatoes. They found that the efficacy of some new numbered products from Gowan for management of Meloidogyne incognita showed promising results.  Meanwhile, in New Mexico, work has progressed on nematicide trials in vineyards. Wine distribution, sales, and consumption in New Mexico generates ~$876.7 million in annual economic activity. In 2017, the industry generated ~$51.6 million in state and local taxes, and $55.4 million in federal taxes. Nematodes can cause premature vineyard decline, reduced vine vigor, and increased fungal infection and virus transmission with yield losses of >60% due to nematodes (Teliz et al., 2007). Recent developments of new nematicides necessitate investigations into these new chemistries their integration with New Mexico cultural practices. A field study at the University of New Mexico was initiated in the spring of 2020 to measure Meloidogyne incognita management and wine-grape yield response to fluensulfone (Nimitz®) compared to spirotetramat (Movento®) and an untreated control.  As anticipated, yields were not significantly improved by either of the spring nematicide treatments at any of the vineyard sites evaluated. This was the first year of the trial, and treatments applied this year have the best opportunity to influence grape yields more directly in 2021. In order to be effective, the nematicidal treatments in vineyards must be applied to the soil environment during the time when there is the highest probability that the vulnerable life stage of the pathogen will also be present in the soil matrix. However, little is known about the seasonal population dynamics of Meloidogyne incognita race 3 (southern root-knot nematode -SRKN) in wine grape vineyards of southern New Mexico. To investigate this, a monitoring study has been initiated this year that will attempt to track soil temperature, soil presence of SRKN juveniles and SRKN egg production on the roots of grapevines of varying rootstocks in a vineyard in Dona Ana County, NM. This information will contribute to improved efficacy of chemical management tools that target the particular life-stage of this nematode in the ever-growing number of vineyards in this region. Lastly, there has been work performed at the University of Hawaii to study nematicide treatments to control nematodes in pineapple. Chemical approaches to management of plant-parasitic nematodes was a common approach amongst producers, and multiple preplant chemicals, including fumigant nematicides such as 1,3-D, methyl bromide, EDB, fenamiphos, and postplant organophosphates and carbamates, were incorporated into the pineapple cropping system. Many of these chemicals have been removed from the market and are no longer available for use in any cropping system. Consequently, replacement options are needed. The efficacy of preplant crown dips with abamectin or fluopyram was tested on pineapple establishment and growth in soil infested with Rotylenchulus reniformis. Plants not infected with nematodes grew better than plants treated with abamectin, fluopyram, or left untreated. Nematode populations were low in all treatments. These chemicals may not have utility as preplant dips in pineapple. Researchers in Hawaii have also studied Entomopathogenic nematode (EPNs) as a method of insect control. EPN live bombs hold promise as a novel biocontrol agent delivery method, however the bombs have not performed well. Laboratory experiments with 0.2 g, 2-2.5 cm mealworm larvae yielded an average of 7,842 IJ S. feltiae over a 27-day period. The mealworms produced 3,555 IJ of H. indida and 7,035 Oscheius sp. Not all of the mealworm larvae were successfully infected by the EPN. The number of cadavers recovered from an infection court varied from 100 to 10% infection. Infection averaged 71% with S. feltiae, 97% with H. indica and 100% with Oscheius. IJ emergence also varied by time. Two peaks of IJ of S. feltiae were observed, the first at 15 days and a second at 22 days after placement into the infection court. A similar peak was observed at 15 days in H. indica and Oscheius. From the literature, emergence of S. feltiae peaks at 15 days in Galleria mellonella. Emergence of H. indica has a similar peak at 14 days in Temnorhynchus baal larvae. The rate of emergence of Oscheius is not as clear. The first peaks observed in the current experiment fit the behavior of S. feltiae and H. indica, however the second peaks are puzzling. In the next set of experiments, insect death at 24 and 48 hours after introduction to the infection court will be noted. This work will help us understand how to improve EPN as a biocontrol tool. Biotechnology offers new approaches to nematode control and will reduce the reliance on nematicides, which are often expensive. In a biotechnology project from UCR, researchers have identified a negative regulator of root-knot nematode immunity in Arabidopsis and have shown that the absence of this gene results in over 50% decrease in RKN infection. To assess the role of this gene in tomato, they developed CRISPR-Cas9 constructs to target the tomato putative ortholog(s) of the Arabidopsis gene.  Several primary tomato transformants were obtained and a few made it to maturity. A number of putative transgenic plants were lost due to lack of daily care because of the pandemic lockdown. Sequence analysis indicated that the CRISPR edited plants had point mutations and were all heterozygous for the mutations. All transgenic plants that made it to maturity were able to set fruits with seeds. The seeds will be planted to obtain homozygous mutants for evaluation with RKN.  Additional tomatoes are being transformed to obtain several independent CRISPR edited lines for future studies. These “biotech” tomatoes may have novel root-knot nematode resistance. With the view that it is important to identify additional biological mechanisms that can be used to develop novel and durable crop resistance against nematodes, researchers at Davis are interested in further understanding the mechanisms by which plants recognize and defend themselves against nematodes. Basal plant immune responses (also known as PAMP-triggered immunity, PTI) can help defend plants against nematodes. However, mechanisms that underlie the activation of PTI in plant-nematode interactions remain unclear. Davis researchers and their collaborators previously identified a plant receptor (NILR1) that is involved PTI activation upon nematode infection. However, the identity of nematode PAMP whose perception is mediated by NILR1 remains unknown. They are now focusing on isolating nematode-derived peptides whose perception is mediated by NILR1 and how the activation of NILR1 is linked to downstream immune signaling. The research plan focuses initially on the model plant Arabidopsis thaliana and its interaction with cyst nematode and root-knot nematode. However, the knowledge gained will be transferred to crop plants during the subsequent years, particularly to rice, soybean (Glycine max), almond (Prunus dulcis), tomato (Lycopersicon esculentum) and sugar beet (Beta vulgaris). Biotechnology has also provided breakthrough in understanding soybean cyst nematode resistance. A Glycine max (soybean) hemicellulose modifying gene, xyloglucan endotransglycoslase/hydrolase (XTH43), is expressed within an Heterodera glycines-induced nurse cell known as a syncytium developing within the soybean root undergoing a defense response. Transgenically expressing XTH43 in Gossypium hirsutum (upland cotton) resulted in an 18% decrease in galls, 70% decrease in egg masses, 64% decrease in egg production and a 97% decrease in second stage juvenile (J2) production as compared to transgenic controls, but did not significantly affect root mass. The results demonstrate XTH43 expression functions effectively in impairing the development of M. incognita (Niraula et al. 2020a). XTH is a secreted protein. Secreted proteins move through the cell in various ways involving two major pathways, the anterograde and retrograde transport. The universal eukaryotic conserved oligomeric Golgi (COG) complex, functioning in retrograde trafficking maintains the correct Golgi structure and function. The COG complex is composed of 8 subunits COGs1-4 compose Sub-complex A while COGs5-8 compose Sub-complex B. Functional transgenic studies demonstrate at least one paralog of each COG gene family functions in G. max during H. glycines resistance (Lawaju et al. 2020). Anterograde transport can culminate through the action of the exocyst. The G. max exocyst is encoded by 61 genes: 5 EXOC1 (Sec3), 2 EXOC2 (Sec5), 5 EXOC3 (Sec6), 2 EXOC4 (Sec8), 2 EXOC5 (Sec10) 6 EXOC6 (Sec15), 31 EXOC7 (Exo70) and 8 EXOC8 (Exo84) genes. At least one member of each gene family is expressed within the syncytium during the defense response. Syncytium-expressed exocyst genes function in defense while some are under transcriptional regulation by mitogen-activated protein kinases (MAPKs) (Sharma et al. 2020). G. max has 32 mitogen activated protein kinases (MAPKs) with nine of them exhibiting defense functions to H. glycines. RNA seq analyses of transgenic G. max lines overexpressing (OE) each defense MAPK has led to the identification of 309 genes that are increased in their relative transcript abundance. Here, 71 of those genes have measurable amounts of transcript in H. glycines-induced syncytia undergoing a defense response. The 71 genes have been grouped into 7 types, based on their expression profile. Overexpression experiments that increase the relative transcript abundance of the candidate defense gene reduces the ability that the plant parasitic nematode Heterodera glycines has in completing its life cycle while, in contrast, RNAi of these genes leads to an increase in parasitism. The results provide a genomic analysis of the importance of MAPK signaling in relation to the secretion apparatus during the defense process defense in the G. max-H. glycines pathosystem and identify additional targets for future studies (Niraula et al. 2020).

Publications

Refereed Journal Articles: Avelar, Sofia, Roberto Ramos-Sabrinho, Kassie Conner, Robert L. Nichols, Kathy Lawrence, and Judith K. Brown. 2020. Characterization of the Complete Genome and P0 Protein for a Previously Unreported Genotype of Cotton Leafroll Dwarf Virus, an Introduced Polerovirus in the United States. Plant Disease 104:780-786. doi.org/10.1094/PDIS-06-19-1316-RE Anjam, M. S., Shah, S. J., Matera, C., Rozanska, E., Sobczak, M., Siddique, S., and Grundler, F. M. W. 2020. Host factors influence the sex of nematodes parasitizing roots of Arabidopsis thaliana. Plant Cell Environ 43:1160-1174. Dyer, David R., William Groover, Kathy S. Lawrence. 2020. Yield loss of cotton cultivars due to Rotylenchulus reniformis and the added benefit of a nematicide. Plant Health Progress 21:113-118. <a href="https://doi.org/10.1094/PHP-10-19-0073-RS">https://doi.org/10.1094/PHP-10-19-0073-RS</a> Groover, W., K. S. Lawrence, and P. Donald. 2020. Temporal distribution of plant-parasitic  nematodes on select bermudagrass sites in Alabama. Nematropica 50:77-85. <a href="https://journals.flvc.org/nematropica/article/view/124876">https://journals.flvc.org/nematropica/article/view/124876</a> Groover, W., and K. S. Lawrence. 2020. Plant health evaluations of Belonolaimus longicaudatusand Meloidogyne incognita colonized bermudagrass using remote sensing. Journal of Nematology 52:1-13. DOI: 10.21307/jofnem-2020-109. Groover, Will, David Held, Kathy Lawrence, and Kendra Carson. 2020. Plant growth-promoting rhizobacteria: a novel management strategy for Meloidogyne incognita on turfgrass. Pest Management Science DOI 10.1002/ps.5867. Gutbrod, P., Gutbrod, K., Nauen, R., Elashry, A., Siddique, S., Benting, J., Dormann, P., and Grundler, F. M. W. 2020. Inhibition of acetyl-CoA carboxylase by spirotetramat causes growth arrest and lipid depletion in nematodes. Scientifc Reports 10:12710. Hamada, N., Yimer, H. Z., Williamson, V. M., and Siddique, S. 2020. . Chemical hide and seek: nematode’s journey to its plant host. Molecular Plant, 13 (2):1-2. Handoo, Z. A., Skantar, A. M., Kantor, M. R., Hafez, S. L., and Hult, M. N. 2020a. Molecular and morphological characterization of the amaryllis lesion nematode, Pratylenchus hippeastri (Inserra et al., 2007), from California. J Nematol 52:1-5. Handoo, Z. A., Skantar, A. M., Hafez, S. L., Kantor, M. R., Hult, M. N., and Rogers, S. A. 2020b. Molecular and morphological characterization of the alfalfa cyst nematode, Heterodera medicaginis, from Utah. J Nematol 52:1-4. Hiltl C, Siddique S. New Allies to Fight Worms. Nature Plants, 6: 598-599. Kantor, M.R., Z.A. Handoo, A.M. Skantar, M.N. Hult, R.E. Ingham, N.M. Wade, W. Ye, G.R. Bauchan, and J.D. Mowery. 2020. Morphological and molecular characterization of Punctodera mulveyi n. sp. (Nematoda: Punctoderidae) from a golf course green in Oregon, USA, with a key to species of Punctodera. Nematology (in press). Kranse O, Beasley B, Adams S, da Silva AP, Bell C, Lilley C, Urwin P, David Bird D, Miska E, Smant G, Gheysen G, Jones J, Viney M, Abad P, Maier TR, Baum TJ, Siddique S, Williamson V, Akay m, Eves-van den Akker S (2020). Towards genetic modification of plant-parasitic nematodes: delivery of macromolecules to adults and expression of exogenous mRNA in second stage juveniles. G3:GENES, GENOMES, GENETICS. ** IN PRESS **. Lawaju BR, Prakash P, Lawrence GW, Lawrence KS, Klink VP. 2020. The Glycine max conserved oligomeric Golgi (COG) complex functions during a defense response to Heterodera glycines. Frontiers in Plant Science doi: 10.3389/fpls.2020.564495. Niraula PM, Lawrence KS, Klink VP. 2020a. The heterologous expression of a soybean (Glycine max) xyloglucan endotransglycosylase/hydrolase (XTH) in cotton (Gossypium hirsutum) suppresses parasitism by the root knot nematode Meloidogyne incognita. PlosOne 15:e0235344. doi: 10.1371/journal.pone.0235344. Niraula PM, Sharma K, McNeece BT, Troell HA, Darwish O, Alkharouf NW, Lawrence KS, Klink VP. 2020b. Mitogen activated protein kinase (MAPK)-regulated genes with predicted signal peptides function in the Glycine max defense response to the root pathogenic nematode Heterodera glycines PlosOne, <a href="https://doi.org/10.1371/journal.pone.0241678">https://doi.org/10.1371/journal.pone.0241678</a>). Powers, T., Harris, T.S., Higgins, R.S., Mullin, P.G. and Powers, K.S., 2020. Nematode biodiversity assessments need vouchered databases: A BOLD reference library for plant-parasitic nematodes in the superfamily Criconematoidea. Genome, (ja). https://doi.org/10.1139/gen-2019-0196 Sharma, Keshav, Prakash M. Niraula, Hallie A. Troell, Mandeep Adhikari, Hamdan Ali Alshehri, Nadim W. Alkharouf, Kathy S. Lawrence & Vincent P. Klink. 2020. Exocyst components promote an incompatible interaction between Glycine max (soybean) and Heterodera glycines (the soybean cyst nematode). Scientific Reports 10:15003. doi.org/10.1038/s41598-020-72126-z Singh, R. R., Verstraeten, B., Siddique, S., Tegene, A. M., Tenhaken, R., Frei, M., Haeck, A., Demeestere, K., Pokhare, S., Gheysen, G., and Kyndt, T. 2020. Ascorbate oxidation activates systemic defence against root-knot nematode Meloidogyne graminicola in rice. Journal of Experimental Botany 71:4271-4284. Subedi, Pratima, Kaitlin Gattoni, Wenshan Liu, Kathy S. Lawrence, and Sang-Wook Park, 2020. Current utility of plant growth–promoting rhizobacteria as biological control agents towards plant-parasitic nematodes. MDPI Plants 9: 1167. DOI:10.3390/plants9091167 Velasco-Cruz, C., G. Giese, D. Saldaña-Zepeda, J. Beacham. 2020. Modeling nematode population dynamics using a multivariate poisson mixture model. Journal of Applied Statistics. (in review) Waisen, P., Z. Cheng, B.S. Sipes, J. DeFrank, S.P. Marahatta, and K.-H. Wang. 2020. Effects of biofumigant crop termination methods on suppression of plant-parasitic nematodes. Applied Soil Ecology 154:103595. <a href="https://doi.org/10.1016/j.apsoil.2020.103595">https://doi.org/10.1016/j.apsoil.2020.103595</a>  Zhang, L. and Gleason C., “Enhancing potato resistance against root-knot nematodes using plant elicitors delivered by bacteria.” Nature Plants, 6, pages 625–629   Extension publications: Cynthia Gleason and Sagar Sathuvalli “Genetic Diversity in Columbia Root-Knot Nematode, and a Request for Help in Research” Potato Progress Vol XX, No. 13, 2020 Lei Zhang and Cynthia Gleason “Loop-Mediated Isothermal Amplification for the Diagnostic Detection of Meloidogyne chitwoodi,” Potato Progress Vol XX, No. 1, 2020 Book chapters: Lawrence, Kathy S. 2020. Reniform nematode (Rotylenchulus reniformis) and its interactions with cotton (Gossypium hirsutum) Chapter 14: pages XX-XX in Integrated nematode management: state of the art and visions for the future. eds Richard Sikora, Johan Desaeger and Leendert Molendijk for CABI. (In press.) Lawrence, K. S. and G. W. Lawrence. 2020. Plant-Parasitic Nematode Management Chapter 12: pages 164-180 in Conservation Tillage Systems: Production, Profitability and Stewardship. eds J. Bergtold, R. Raper, G. Hawkins, and K. Iversen. CRC Press LLC. Roberts, P.A. 2020. Integrated management of root-knot and other nematodes in food legumes. Pp.1-9 in Integrated nematode management: state of the art and vision for the future. Sikora, R., et al., (eds.). (In press). Published Abstract: Kathy S. Lawrence, Austin Hagan, Randy Norton, Jiahuai Hu, Travis R. Faske, Robert B Hutmacher, John Muller, Ian Small, Zane J. Grabau, Robert C. Kemerait, Doug Jardine, Paul Price, Thomas W. Allen, Calvin D Meeks, John Idowu, Lindsey D. Thiessen, Seth A. Byrd, Jerry Goodson, Heather Kelly, Terry Wheeler, Thomas Isakeit and Hillary L. Mehl. 2020. Cotton Disease Loss Estimate Committee Report, 2020.         Proceedings of the 2020 Beltwide CottonConference Vol. 1: 117-119. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm</a> Heather Kelly, Rachel R. Guyer, Shelly Neill Pate, Thomas W. Allen, Tessie H. Wilkerson, P. D. Colyer, Thomas Isakeit, Robert C. Kemerait, Kathy S. Lawrence, Hillary L. Mehl, Paul Price, Alejandro Rojas, Lindsey D. Thiessen and Terry A. Wheeler. 2020. Report of the Cottonseed treatment committee for 2019. Proceedings of the 2020 Beltwide Cotton Conference Vol. 1: 393-402. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm</a> Kathy S. Lawrence, Tyler Sandlin, Andy Page, Tyson B Raper, Heather Kelly, Brad Meyer and Nathan Silvey. 2020.  <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/data/conferences/2020/paper/19671.pdf">Cotton Cultivar Disease Incidence, Severity, and Yields When Challenged with Verticillium Wilt in the Tennessee Valley Region, 2019</a>. Proceedings of the 2020 Beltwide Cotton Conference Vol. 1: 112-116. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm</a> Kara Gordon, Kathy S. Lawrence, Drew Schrimsher and Brad Meyer. 2020. A Cost-Effective Prescription Management Strategy Utilizing Fertilizers and Nematicides to Combat Yield Losses from Rotylenchulus reniformis on Cotton. Proceedings of the 2020 Beltwide Cotton Conference Vol. 1: 169-171. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm</a> Bisho Ram Lawaju and Kathy S. Lawrence. 2020. Evaluation of Salibro as a New Nematicide for Cotton Production Systems.  Proceedings of the 2020 Beltwide Cotton Conference Vol. 1: 458-463. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm</a> Drew Schrimsher, Brad Meyer, Kathy S. Lawrence, Bisho Ram Lawaju, Marina Rondon, Will Groover, David R Dyer and Kara Gordon. 2020. Cotton Cultivar Response to CLRDV as Influenced By Planting Dates.  Proceedings of the 2020 Beltwide Cotton Conference Vol. 1: 388-391. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm</a> Marina Nunes Rondon and Kathy Lawrence. 2020. G143A Mutation in the Cytochrome B Gene Detected from Corynespora cassiicola Isolates in Alabama.  Proceedings of the 2020 Beltwide Cotton Conference Vol. 1: 202-206. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm</a> Shelly Neill Pate, Heather Kelly, Rachel R. Guyer, Thomas W. Allen, Tessie H. Wilkerson, P. D. Colyer, Kathy S. Lawrence, Thomas Isakeit, Robert C. Kemerait, Hillary L. Mehl, Paul Price, Alejandro Rojas, Lindsey D. Thiessen and Terry A. Wheeler. 2020. An Assessment of Seed Treatment Efficacy and Cotton Seedling Disease Presence Using Innovative Techniques. Proceedings of the 2020 Beltwide Cotton Conference Vol. 1: 327-328. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm</a> Travis R. Faske, Thomas W. Allen, Zane J. Grabau, Jiahuai Hu, Robert C. Kemerait, Kathy S. Lawrence, Hillary L. Mehl, John Mueller, Paul Price, Lindsey D. Thiessen, and Terry A Wheeler. 2020. Beltwide Nematode Research and Education Committee Report on Field Performance of Seed and Soil-Applied Nematicides, 2019. Proceedings of the 2020 Beltwide Cotton Conference Vol. 1: 192-196. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm</a> R. Dyer, K.S. Lawrence, W. Groover, D. Dyer, M. Rondon, K. Gattoni, W. Sanchez, K. Gordon. 2020. Evaluation of nematicide products for increasing cotton plant growth and yield and decreasing reniform nematode population density on cotton in North Alabama, 2019. Plant Disease Management Reports 14:N007. The American Phytopathological Society, St. Paul, MN. <a href="https://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2020/N007.pdf">https://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2020/N007.pdf</a> R. Dyer, K.S. Lawrence, W. Groover, D. Dyer, M. Rondon, K. Gattoni, W. Sanchez, K. Gordon. 2020. Evaluation of Salibro for increasing cotton plant growth and decreasing root-knot nematode population density and fusarium wilt incidence on cotton in central Alabama, 2019. Disease Management Reports 14:N006. The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2020/N006.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2020/N006.pdf</a> Kara Gordon, K.S. Lawrence, W. Groover; D. Dyer; M. Rondon, W. Sanchez. 2020. Management strategies utilizing nematicides to combat yield loss from reniform nematode on cotton, 2019. Plant Disease Management Reports 14:N013. The American Phytopathological Society, St. Paul, MN. <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2020/N013.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2020/N013.pdf</a>  B.R. Lawaju, K.S. Lawrence, W. Groover, D. Dyer, M. Rondon, K. Gattoni, W. Sanchez, K. Gordon. 2020. Evaluation of fungicides for management of damping-off in cotton in north Alabama, 2019.Plant Disease Management Reports 14:CF054. The American Phytopathological Society, St. Paul, MN.  <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2020/CF054.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2020/CF054.pdf</a> B.R. Lawaju, K.S. Lawrence, W. Groover, D. Dyer, M. Rondon, K. Gattoni, W. Sanchez, K. Gordon. 2020.  Combinations of seed treatments for seedling disease management in cotton in northern Alabama, 2019. Plant Disease Management Reports 14:CF053. The American Phytopathological Society, St. Paul, MN.  <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2020/CF053.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2020/CF053.pdf</a> B.R. Lawaju, K.S. Lawrence, W. Groover, D. Dyer, M. Rondon, K. Gattoni, W. Sanchez, K. Gordon. 2020. Fungicide seed treatments for management of seedling disease in cotton in northern Alabama, 2019. Plant Disease Management Reports 14:CF052. The American Phytopathological Society, St. Paul, MN.  <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2020/CF052.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2020/CF052.pdf</a> Marina Nunes Rondon, K.S. Lawrence, W. Groover; D. Dyer, B.R. Lawaju, K. Gordon. 2020. Nematicide seed treatments for reniform nematode management on soybean in north Alabama, 2019. Plant Disease Management Reports 14:CF038. The American Phytopathological Society, St. Paul, MN.  <a href="http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2020/CF038.pdf">http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2020/CF038.pdf</a>

Impact Statements

Nematicide efficacy studies and insights into the population dynamics of Meloidogyne incognita in vineyards will provide valuable management insights to New Mexico and its regional agricultural industry.

Date of Annual Report: 01/01/1970

Report Information

Annual Meeting Dates: 11/15/2021 - 11/16/2021
Period the Report Covers: 01/01/1970 - 01/01/1970

Participants

Officers
Chair: Cynthia Gleason
Vice Chair: Kathy Lawrence
Secretary: Shahid Siddique
USDA Administrator: Isgouhi Kaloshian

W4186 Meeting Participants:
Gleason, Cynthia (Washington State University)
Ingham, Russell (Oregon State University)
Kaloshian, Isgouhi (University of California-Riverside)
Lawrence, Kathy (Auburn University)
Melakeberhan, Haddish (Michigan State University)
Roberts, Phil (University of California-Riverside)
Siddique, Shahid (University of California-Davis)
Sipes, Brent (University of Hawaii)
Groen, Nils (University of California-Riverside)
Dandurand, Louise-Marie (University of Idaho)
Thomas, Steve (University of New Mexico)

Absent: Hafez, Saad (University of Idaho), Powers, Tom (University of Nebraska), Beacham, Jacqueline (University of New Mexico)

Brief Summary of Minutes

Project/Activity Number: W4186

Project/Activity Title: Variability, Adaptation and Management of Nematodes Impacting Crop Production and Trade

Period Covered: 2021

Date of This Report: 1/12/2022

Annual Meeting Date(s): November 15-16, 2021

Venue: University of Hawai’i, Hawaii

Brief summary of minutes of annual meeting:

Kathy Lawrence discussed her latest research on nematode-resistant [reniform and root-knot nematode (RKN)] cotton varieties and nematicides applications. Use of reniform-resistant cotton increased yield by 877 kg/ha and reduced nematode population by 83%. The effect on yield was less significant in case of RKN resistant cotton.

Louise-Marie Dandurand discussed status of potato cyst nematode (Globodera pallida) in Idaho. DSSAT (Decision Support System for Agrotechnology Transfer) growth model was used to predict potato yield reduction in relation to initial G. pallida population. US varieties are susceptible to G. pallida. Various breeding programs are underway to integrate resistance into potato. A 3-year rotation experiment involving litchi tomato and barley is currently underway.

Cynthia Gleason updated progress on development of tools for molecular identification of Meloidogyne chitwoodi. Efforts are underway to develop race-specific primers through various approaches including whole-genome sequencing.

Shahid Siddique gave an update about the progress on characterization of PSY peptides in M. javanica. Whole genome sequencing of M. javanica wild-type strain (VW4) and resistant-breaking strain (VW5) is currently underway. Tools for genetic transformation of M. hapla are being developed.

Simon Niels Goren is a new faculty member at UCR. He updated the group about his research plans to work on plant toxins and the evolution of host-parasite interactions.

Phil Roberts updated on RKN resistance trait in carrots. Resistance markers were developed against M. hapla in carrot cultivar “Homs”. Ongoing efforts in resistance screening against M. javanica and M. incognita were discussed.

Haddish Melakeberhan discussed parasitic variability in M. hapla. A look at the enrichment index and structure index-based Soil Food Web model shows that conditions that favor presence of M. hapla also favor presence of other nematodes. Haddish discussed nematode management strategies using Soil Food Web (SFW) and Fertilizer Use Efficiency (FUE) models.

Russel Ingham talked about RKN infection problems in potato. He discussed nematode suppression by green manure cover crops.

Steve Thomas presented for Jacki Beacham who could not attend the meeting. Ditylenchus dipsaci was found last year from New Mexico. Garlic but not alfalfa often has stem nematode. Temporal studies were conducted on Vitis vinifera for M. incognita detection and to determine the optimal time for nematicide application.

Brent Sipes updated on issues related to poor survival of native plants in areas around the University of Hawaii Campus. Various native plants were tested for infection by RKN and reniform nematodes. In general, a lot of variation was observed for nematode reproduction factor on native plants for reasons not clear. A survey of M. enterolobii was conducted on Asian vegetables and Asian perennials that are potentially imported as rooted plants. Meloidogyne enterolobii was never detected.

Business

Business Meeting: Nov 15, 2021

Following items were discussed,

Location: Davis was selected as a location for 2022 meeting. Shahid will check potential dates (beginning to mid November 2022).

Officer’s Election: Haddish Melakeberhan was elected as secretary unanimously. Louise-Marie Dandurand volunteered to be the new secretary in year 2022.
Kathy Lawrence will move to become the chair.
Shahid Siddique will move to become the vice chair.

Reports: Reports for 2021 should be sent to Cynthia Gleason before Christmas.

New Members: Chair Kathy Lawrence will write to Peter DiGenarro (University of Florida), Chris Taylor (Ohio State University), Triston Watson (Louisiana State University), Travis Faske (University of Arkansas), Inga Zasada (USDA, Corvallis, OR) and Zhang Lei (Purdue University) inviting them to join the group.

Project Renewal: Project renewal is due in 2023. So, we will have to think about renewing the project already next year. Phil Roberts will send previous project proposal to the group.

Accomplishments

Objective 1:   Characterize genetic and biological variation in nematodes relevant to crop production and trade. Plant-parasitic nematodes are a large diverse group of roundworms that cause significant agricultural crop losses. These losses are estimated to be at least $8 billion in the United States and $80 billion worldwide. Therefore, it is important to understand and characterize the genetic and biological variation of plant parasitic nematodes. These variations may affect nematode virulence and/or host range, with implications relevant to crop production and trade. The following activities have been performed regarding objective 1. Several researchers in the project work on potato-nematode interactions.  Washington/Oregon/Idaho produce the majority of the potatoes grown in the USA. Meloidogyne chitwoodi is a major problem for potato producers in this region because the nematode causes tuber defects that can significantly diminish the value of the crop. There are different isolates of M. chitwoodi present in the region that differ in virulence and host range. Therefore, nematode management strategies are impacted by the specific isolate present. Researchers at Washington State University have sequenced the genomes of three M. chitwoodi isolates and have developed molecular diagnostic tools, such as molecular beacon assays, for M. chitwoodi.   Another important potato nematode is the pale cyst nematode, Globodera pallida. This quarantine pathogen is found only in a small section of Idaho, but its potential spread threatens the entire US potato industry. Researchers at the University of Idaho have recently initiated a project to determine the genetic diversity found in Globodera spp. They will then work on development of resistant potatoes suitable for US growers and the potato industry by finding appropriate sources of resistance that encompass the genetic diversity found in Globodera spp. Populations from Chile and Peru are being characterized for genetic diversity by various sequencing efforts.   Objective 2:  Determine nematode adaptation processes to hosts, agro-ecosystems and environments. A number of actions have been performed under objective 2 (studying nematode adaptation to climatic conditions, cropping systems, and/or soil properties).  For example, researchers at Michigan State University have analyzed the parasitic variability (PV) of the Northern root-knot nematode (M. hapla) populations in Michigan. Meloidogyne hapla is a major RKN found in temperate climates. One question was whether PV exists in M. hapla because it is adapted to diverse soil health conditions. In order to answer this question, M. hapla distribution by soil groups (mineral and muck) and soil health conditions, as described by the nematode community analyses-based soil food web (SFW), was characterized in 15 fields (6 muck and 9 mineral soils) across three vegetable production regions of Michigan. A second question was whether there is an association, or the lack of, between the presence of M. hapla and specific biophysicochemical conditions. The Michigan researchers performed principal component analyses among M. hapla presence, soil groups, and nematode abundance parameters and showed general similarity between mineral and muck soils. On-going analyses are going to help determine relationships among PV, soil health, microbiome and soil physicochemical parameters. This information will set the foundation for more targeted investigations to understand any links between M. hapla’s PV and its soil environment. A major research focus at Michigan State University has been on modifications of the soil food web and fertilizer use efficiency models. These may be used as diagnostic tools to get in-depth and systematic understanding of cause-and-effect relationships and to extract potential practical applications of research outcomes. Michigan researchers have recently published how the soil food web model can be used to translate complex biophysicochemical soil health outcomes into practical applications and the fertilizer use efficiency model to assess the sustainability of the outcomes. Another aspect of objective 2 has been to look at distribution of nematodes in terms of adaption to various hosts. For example, the University of Hawaii has surveyed native plants in areas around University of Hawaii Campus for susceptibility to RKN and reniform nematodes. For reniform nematodes, the native plant Ipomoea appeared to be a good host, but most native plants seemed to be poor hosts to these nematodes. The observed variation of resistance in seedlings may reflect the variation in the seed germplasm. In addition, there was also concern that the quarantine nematode M. enterolobii may have been recently introduced into Hawaii. A survey of Asian vegetables and Asian perennials (Earpod, Guava, Mango, Avocado, Jabong, Breadfruit, Jackfruit, Banana, Cacao, Papaya, Jaboticaba, Pineapple, Cherimoya etc.) was conducted. Fortunately, M. enterolobii was not detected in any samples. In New Mexico, researchers have studied nematodes from samples that were taken as part of a rangeland research project evaluating the displacement of native grasses by an invasive grass planted by a local utility company. Morphological identification of the fixed specimen has been on-going with the assistance of Paul DeLey (UC-Riverside). A new nematode genus and species was discovered at 3 locations within the experiment site. The new genus appears closely related to the family Anguinidae (a diverse plant parasitic family mostly infecting grasses) but differs in a key diagnostic character from all known species of that family.   Objective 3:  Develop and assess nematode management strategies in agricultural production systems.    There is a continued need for new safe, effective, and inexpensive nematode control options. A number of studies presented below have been performed to address objective 3, the development and assessment of nematode management strategies. Starting with chemical controls, nematicides offer an effective means of nematode management, but as companies develop new nematicides, it is important to investigate the effectiveness of their formulations or their application methods. Research at Auburn University focuses on chemical management strategies to reduce root-knot and reniform populations on cotton. The objective of their research was to integrate additional fertilizer and nematicide combinations into current practices to establish economical nematode management strategies while promoting cotton yield and profit. Microplot and field trials were run to evaluate fertilizer and nematicide combinations applied at the pinhead square (PHS) and first bloom (FB) plant growth stages to reduce nematode population density and promote plant growth and yield. Cost efficiency was evaluated based on profit from lint yields and chemical input costs. For example, in M. incognita field trials, a nematicide seed treatment + nematicides (28-0-0-5 + Vydate® C-LV + Max-In® Sulfur) applied at the pinhead square (PHS) and first bloom (FB) plant growth stages supported the largest lint yields and profit per hectare at $784. These results suggest that combinations utilizing fertilizers and nematicides in addition to current fertility management show potential to promote yield and profit in R. reniformis and M. incognita infested cotton fields. In New Mexico, researchers have been studying nematicide treatments in relation to wine grape yield. The goal of their vineyard research was to study M.  incognita management and wine-grape yield response to fluensulfone (Nimitz®) compared to spirotetramat (Movento®) and an untreated control. Interestingly, neither of the nematicides were effective in improving yield greater than that in the untreated control in this second year of the study. Mean RKN recovery from the soil was lower in the Nimitz®-treated plots compared to the untreated control at only one of the three vineyards. In order to better understand how different vineyard drip irrigation strategies result in differences in roots and RKN distributions in the soil, an assessment was conducted in New Mexico in the spring of 2021. The study revealed that roots and RKN were very closely correlated with the location of the drip emitters at the vineyard with the single drip line, whereas they were equitably distributed in the 4’ x 4’ area around the vine at the vineyard with two drip lines, 12” on either side of the vine row. This may help explain the improved efficacy of control of the RKN at the vineyard with the single drip line versus the poor control at the vineyard with a more broadcast distribution of RKN. Currently University of New Mexico researchers are conducting temporal studies to determine the optimal time for nematicide application. Every two weeks for the next two years, soil and roots from multiple sites in a vineyard will be sampled. RKN juvenile populations in the soil and roots and soil temperatures are being continuously recorded and will be used to try and determine a degree day reference for nematicide applications in vineyards. To move away from synthetic nematicides, researchers at the University of Idaho have looked at plants as the sources of novel chemistries for the development of bionematicides. They continue to evaluate potential nematicidal compounds isolated from the trap crop Solanum sisymbriifolium. High levels of solamargine have been extracted from roots of this trap crop. Fractions extracted from this plant have been found to be highly toxic to G. pallida, and reduce hatch, infection and reproduction of the nematode. Solanum sisymbriifolium is also resistant to RKN, indicating that it has broad spectrum nematode resistance. Other approaches to nematode control, aside from chemicals, include host plant resistance, green manures, and biological controls. In terms of green manure, work from Oregon State University determined the reproduction of the Columbia RKN (CRKN, Meloidogyne chitwoodi) for green manure plants.  Four mustard cultivars were good hosts for the nematode, but not as good as wheat. An oilseed radish (Terranova) and one sorghum x sudagrass hybrid (Sordan 79) were both nonhosts. When infested soil was amended with green vegetation, wheat-amended pots had few live nematodes, but the fewest live juveniles were recovered from sudangrass-amended pots in which live J2 were reduced over 92% compared to wheat-amended pots. However, none of the amendments had any effect on the ability of the surviving J2 to reproduce when a good host (wheat) was planted in the amended soil. Efforts to move away from nematicide use in potato have also been undertaken. Researchers at Washington State University engineered the bacteria Bacillus subtilis to produce and secrete the defense elicitor called Pep1. By treating the potato plants with B. subtilis that secretes the Pep1 defense elicitor, the plants became more resistant against M. chitwoodi. They have also treated tomato with B. subtilis that secretes the Pep1 and found protection against M. hapla, indicating that the transgenic bacteria can provide protection to a variety of plants against RKN. Aside from synthetic and natural treatments, genetic resistance to plant parasitic nematodes would provide another option for nematode control. Currently, resistance to pale cyst nematodes in commercially relevant potato varieties for US growers does not exist. Through collaborations with breeders and plant geneticists, University of Idaho-based research has focused on breeding resistance into russet type potatoes for the US industry. Clones with partial resistance have been developed, and future efforts are focused on pyramiding different sources of resistance to achieve higher levels of resistance to G. pallida. In addition to the development of resistance through traditional breeding efforts, University of Idaho researchers have initiated a project to understand the plant-nematode interaction of Solanum sisymbriifolium. They studied the differential expression of genes in nematodes infecting S. sisymbriifolium. A transcriptome analysis of G. pallida revealed differences in expression of genes important for detoxification as well as parasitism, which gives insights into the mechanism of plant resistance. In addition, field trials have been established to develop a 3-year rotation plan for use in G. pallida infested fields. The rotation compares the use of resistance or a trap crop in rotation with a susceptible potato variety and evaluates G. pallida population decline for each of the rotation plans. Carrots are one of the highest fumigant users. To reduce fumigant usage, researchers at the University of California at Riverside (UCR) have conducted an analysis of RKN resistance traits in carrot to identify and characterize novel resistance genes and their interactions with root-knot nematode species and populations. Resistance traits effective against Meloidogyne incognita were genetically mapped in the carrot genome using greenhouse generated phenotypes from infection assays and single nucleotide polymorphism (SNP) markers from genotyping-by-sequencing. Several sources of resistance in carrot germplasm from Brasilia, South Africa and India were determined to be conferred by at least five genome locations across carrot chromosomes. Candidate genes for the resistance determinants were identified. Because there are not many naturally resistant crops to plant parasitic nematodes, researchers have also looked to engineer plant resistance. Researchers at the University of California, Davis have studied the plant-nematode interaction at the molecular level so that the information can be used to develop new tools of resistance. They have recently identified several PSY-like peptides in RKNs. The MigPSY peptides have a highly conserved region shared with the bacterial pathogen Xanthomonas oryzae pv. Oryzae (Xoo) peptide called RaxX.  Rice plants have a defense receptor protein called XA21 that binds to RaxX and triggers a plant defense response. Therefore, the UCD researchers hypothesized that the XA21 dependent immune response may also be activated by MigPS. They found that rice plants with XA21 (called KitaakeX) had fewer young nematode females, indicating slower or blocked nematode development. They also observed that KitaakeX showed a 37% reduction in the number of eggs per plant compared to wild-type plants. Together, these results suggest that XA21 expression in rice confers resistance to the RKN M. javanica. While these preliminary experiments indicate that rice plants constitutively expressing the XA21 are resistant to nematodes, the underlying mechanism behind this resistance response is unknown.

Publications

Publications Refereed Journal Articles: <ul style="list-style-type: square;"> <li>Bali, S., Zhang, L., Franco, J., Gleason, C., Biotechnological advances with applicability in potatoes for resistance against RKN,(2021) Current Opinion in Biotechnology, 70: 226-233.</li> <li>Bali S., Hu S., Vining V., Brown C., Mojtahedi H., Zhang L., Gleason C., Sathuvalli V. (2021) Nematode genome Announcement: Draft genome of Meloidogyne chitwoodi, an economically important pest of potato in the Pacific Northwest. Molecular Plant Microbe Interactions, 34(8):981-986.</li> <li>Beckmann J.F., Dormitorio T., Oladipupo, S. O., Terra, M. T. B., Lawrence, K., Macklin, K.S., Hauck, R. (2021) Heterakis gallinarum and Histomonas meleagridis DNA Persists in Chicken Houses Years after Depopulation, Veterinary Parasitology, DOI: <a href="https://doi.org/10.1016/j.vetpar.2021.109536">https://doi.org/10.1016/j.vetpar.2021.109536</a></li> <li>Divykriti C, Hasan MH, Matera C, Chitambo O, Mendy B, Mahlitz D, Naz AA, Szumski S, Janakowski S, Sobczak M, Mithöfer A, Kyndt T, Grundler FMW, Siddique S (2021). Plant parasitic cyst nematodes redirect host indole metabolism via NADPH oxidase‐mediated ROS to promote infection. New Phytologist, 232: 318-331.\</li> <li>Hassan, Mohannad K., Kathy S. Lawrence, Edward J. Sikora, Mark R. Liles, and Joseph W. Kloepper (2021) Enhanced biological control of RKN, Meloidogyne incognita, by combined inoculation of cotton or soybean seeds with a plant growth-promoting rhizobacterium and pectin-rich orange peel. Journal of Nematology 53:1-17. DOI: 10.21307/jofnem-2021-058</li> <li>Hesse, C. N., I. Moreno, O. Acevedo Pardo, H. Pcheco Fuentes, E. Grenier, L. M. Dandurand, I. A. Zasada (2021) Characterization of Globodera ellingtonae populations from Chile utilizing whole genome sequencing. Journal of Nematology 53:1-9. <a href="https://doi.org/10.21307/jofnem-2021-08">https://doi.org/10.21307/jofnem-2021-08</a></li> <li>Kantor, M.R., Z.A. Handoo, A.M. Skantar, M.N. Hult, R.E. Ingham, N.M. Wade, W. Ye, G.R. Bauchan, and J.D. Mowery (2021) Morphological and molecular characterization of  Punctodera mulveyi n. sp. (Nematoda: Punctoderidae) from a golf course green in Oregon, USA, with a key to species of Punctodera. Nematology 23: 667-683. DOI::<a href="http://doi.org/10.1163/15685411-bja10068">http://doi.org/10.1163/15685411-bja10068</a>\</li> <li>Klink, Vincent P., Omar Darwish, Nadim W. Alkharouf & Katherine S. Lawrence (2021) The impact of pRAP vectors on plant genetic transformation and pathogenesis studies including an analysis of BRI1-ASSOCIATED RECEPTOR KINASE 1 (BAK1)-mediated resistance. Journal of Plant Interactions, 16:1, 270-283, DOI: 10.1080/17429145.2021.1940328.</li> <li>Land, Caroline J., Gary E. Vallad, Johan Desaeger, Edzard Van Santen, Joe Noling, and Kathy Lawrence (2021) Supplemental fumigant placement improves root-knot and Fusarium wilt management for tomatoes produced on a raised bed, plasti-culture system in Florida’s Myakka fine sand. Plant Disease <a href="https://apsjournals.apsnet.org/doi/pdf/10.1094/PDIS-03-21-0543-RE">https://apsjournals.apsnet.org/doi/pdf/10.1094/PDIS-03-21-0543-RE</a></li> <li>Lartey, I., A. Kravchenko, T. Marsh and H. Melakeberhan (2021) Meloidogyne hapla occurrence relative to nematode trophic group abundance and soil food web conditions in soils and regions of selected Michigan vegetable production fields. Nematology 23: <a href="https://DOI.org/10.1163/15685411-bja10091">https://DOI.org/10.1163/15685411-bja10091</a></li> <li>Lawaju BR, Groover W, Kelton J, Conner K, Sikora E, Lawrence KS (2021) First report of Meloidogyne incognita infecting Cannabis sativa in Alabama. Journal of Nematology. 2021 May 1;53:e2021-52. doi: 10.21307/jofnem-2021-052.</li> <li>Pillai, S. S., and L. M. Dandurand (2021) Effect of steroidal glycoalkaloids on hatch and reproduction of the potato cyst nematode Globodera pallida. Plant Disease <a href="https://doi.org/10.1094/PDIS-02-21-0247-RE">https://doi.org/10.1094/PDIS-02-21-0247-RE</a></li> <li>Pillai, S. S., and L. M. Dandurand. (2021) Potato cyst nematode egg viability assessment and preparasitic juvenile screening using a large particle flow cytometer and sorter. Phytopathology, 111(4), 713-719. <a href="https://doi.org/10.1094/PHYTO-06-20-0255-R">https://doi.org/10.1094/PHYTO-06-20-0255-R</a></li> <li>Powers TO, Harris TS, Higgins RS, Mullin PG, Powers KS. Nematode biodiversity assessments need vouchered databases: A BOLD reference library for plant-parasitic nematodes in the superfamily Criconematoidea. Genome. 2021 Mar;64(3):232-241. doi: 10.1139/gen-2019-0196. Epub 2020 Jun 11. PMID: 32526150.</li> <li>Solo N., J. Kud, A. Caplan, J. Kuhl, F. Xiao, and L. M. Dandurand (2021) Characterization of the superoxide dismutase (SOD) from the potato cyst nematode, Globodera pallida. Phytopathology. <a href="https://doi.org/10.1094/PHYTO-01-21-0021-R">https://doi.org/10.1094/PHYTO-01-21-0021-R</a></li> <li>Marhavy P, Siddique S (2021). Histochemical staining of suberin in plant roots. Bio-protocol, doi: 10.21769/BioProtoc.3904</li> <li>Melakeberhan, H., G. Bonito and A.N. Kravchenko (2021) Application of nematode community analyses-based models towards identifying sustainable soil health management outcomes: A review of the concepts. Soil Systems 5, 32. <a href="https://doi.org/10.3390/soilsystems5020032">https://doi.org/10.3390/soilsystems5020032</a></li> <li>Nyaku, S. T., V. R. Sripathi, K. Lawrence, and G. Sharma (2021) Characterizing repeats in two whole-genome amplification methods in the reniform nematode genome. International Journal of Genomics. <a href="https://doi.org/10.1155/2021/5532885">https://doi.org/10.1155/2021/5532885</a>.\</li> <li>Palomares-Rius JE, Hasegawa K, Siddique S, Vicente CSL (2021). Protecting our crops-approaches for plant parasitic nematode control. Frontiers in Plant Science, 2: 726057</li> <li>Sanchez, WinDi, David Shapiro, Geoff Williams, and Kathy Lawrence (2021) Entomopathogenic nematode management of small hive beetles (Aethina tumida) in three native Alabama soils under low moisture conditions. Journal of Nematology 53:1-14. DOI: 10.21307/jofnem-2021-063</li> <li>Sato K, Uehara T, Holbein J, Sasaki-Sekimoto Y, Gan P, Bino T, Yamaguchi K, Bino T, Yamaguchi K, Ichihashi Y, Maki N, Shigenobu S, Ohta H, Franke B, Siddique S, Grundler FMW, Suzuki T, Kadota Y, Shirasu K (2021) Transcriptomic analysis of resistant and susceptible responses in a new model RKN infection system using Solanum torvum and Meloidogyne arenaria. Frontiers in Plant Science, 12: 680151</li> <li>Skantar A, Handoo Z, Kantor M, Hafez S, Hult M, et al. 2021. First report of Cactodera milleri Graney and Bird, 1990 from Colorado and Minnesota. Journal of Nematology 53:2021-38</li> <li>Velasco-Cruz, C., G. Giese, D. Saldaña-Zepeda, J. Beacham (2021) Modeling nematode population dynamics using a multivariate poisson mixture model. Journal of Applied Statistics: <a href="https://doi.org/10.1080/02664763.2021.1935800">https://doi.org/10.1080/02664763.2021.1935800</a></li> <li>Zhang L. and Gleason, C., (2021) Transcriptome analyses of pre-parasitic and Parasitic Meloidogyne Chitwoodi Race 1 to identify putative effector genes, Journal of Nematology, 53:e2021-84.</li> </ul>  Other: <ul style="list-style-type: square;"> <li>Turner, A. K., Lawrence, K. S., Gordon, K., Dyer, D., Lawaju, B., Rondon, M., Norris, C. 2020. Management strategies utilizing seed treatments to combat yield loss from reniform nematode on cotton. Report No. 15:N010. The American Phytopathological Society, St. Paul, MN. https://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2021/N010.pdf </li> <li>Turner, A. K., Lawrence, K. S., Gordon, K., Dyer, D., Lawaju, B., Rondon, M., Norris, C. 2020. Soybean seed treatment combinations for decreasing reniform nematode population density in North Alabama. Report No.  15:N009. The American Phytopathological Society, St. Paul, MN. https://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2021/N009.pdf </li> <li>Turner, A. K., Lawrence, K. S., Gordon, K., Dyer, D., Lawaju, B., Rondon, M., Richburg, J., Norris, C. 2020. Nematicide and cotton variety combinations for decreasing reniform nematode populations in North Alabama. Report No.15:N016. The American Phytopathological Society, St. Paul, MN.  https://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2021/N016.pdf </li> <li>Turner, A. K., Lawrence, K. S., Gordon, K., Dyer, D., Lawaju, B., Rondon, M., Norris, C. 2020. Nematicide and cotton variety combinations for decreasing RKN populations in Central Alabama. Report No. 15:N017. The American Phytopathological Society, St. Paul, MN. https://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2021/N017.pdf </li> <li>Kathy S. Lawrence, Austin Hagan, Randy Norton, Jiahuai Hu, Travis R. Faske, Robert B Hutmacher, John Muller, Ian Small, Zane J. Grabau, Robert C. Kemerait, Doug Jardine, Paul Price, Thomas W. Allen, Calvin D Meeks, John Idowu, Lindsey D. Thiessen, Seth A. Byrd, Jerry Goodson, Heather Kelly, Terry Wheeler, Thomas Isakeit and Hillary L. Mehl. 2020. Cotton Disease Loss Estimate Committee Report, 2020.         Proceedings of the 2020 Beltwide Cotton Conference Vol. 1: 117-119. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm</a></li> <li>Kara Gordon, Kathy S. Lawrence, Drew Schrimsher and Brad Meyer. 2020. A Cost-Effective Prescription Management Strategy Utilizing Fertilizers and Nematicides to Combat Yield Losses from Rotylenchulus reniformis on Cotton. Proceedings of the 2020 Beltwide Cotton Conference Vol. 1: 169-171. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm</a></li> <li>Bisho Ram Lawaju and Kathy S. Lawrence. 2020. Evaluation of Salibro as a New Nematicide for Cotton Production Systems.  Proceedings of the 2020 Beltwide Cotton Conference Vol. 1: 458-463. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm</a></li> <li>Drew Schrimsher, Brad Meyer, Kathy S. Lawrence, Bisho Ram Lawaju, Marina Rondon, Will Groover, David R Dyer and Kara Gordon. 2020. Cotton Cultivar Response to CLRDV as Influenced By Planting Dates.  Proceedings of the 2020 Beltwide Cotton Conference Vol. 1: 388-391. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm</a></li> <li>Travis R. Faske, Thomas W. Allen, Zane J. Grabau, Jiahuai Hu, Robert C. Kemerait, Kathy S. Lawrence, Hillary L. Mehl, John Mueller, Paul Price, Lindsey D. Thiessen, and Terry A Wheeler. 2020. Beltwide Nematode Research and Education Committee Report on Field Performance of Seed and Soil-Applied Nematicides, 2019. Proceedings of the 2020 Beltwide Cotton Conference Vol. 1: 192-196. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm</a></li> </ul> Extension publications: <ul style="list-style-type: square;"> <li>Ingham. R.E. 2021. Nematode management with oxamyl and Velum Prime. Potato Progress 26 (1): 6-8.</li> <li> Melakeberhan, H. and S. Kekaire (2021). Managing nematodes, cover Crops, and soil health in diverse cropping systems: MSUE Extension Bulletin (E3457). https://www.canr.msu.edu/resources/managing-nematodes-cover-crops-and-soilhealth-in-diverse-cropping-system</li> </ul> Book chapters: Lawrence, Kathy S. 2021. Reniform nematode (Rotylenchulus reniformis) and its interactions with cotton (Gossypium hirsutum) Chapter 14: pages 94-100 in Integrated nematode management: state of the art and visions for the future. eds Richard Sikora, Johan Desaeger and Leendert Molendijk for CABI. DOI: 10.1079/9781789247541.0014

Impact Statements

New knowledge on natural host resistance traits to manage root-knot nematodes in field and vegetable crops was obtained, and this can be adopted by plant breeding programs and the seed industry to benefit growers by producing nematode resistant crop varieties.

Date of Annual Report: 02/13/2023

Report Information

Annual Meeting Dates: 11/14/2022 - 11/15/2022
Period the Report Covers: 10/01/2021 - 09/30/2022

Participants

Siddique, Shahid (University of California-Davis)
Gleason, Cynthia (Washington State University)
Kaloshian, Isgouhi (University of California-Riverside)
Lawrence, Kathy (Auburn University)
Melakeberhan, Haddish (Michigan State University)
Roberts, Phil (University of California-Riverside)
Groen, Niels (University of California-Riverside)
Beacham, Jacqueline (University of New Mexico)
Powers, Thomas (University of Nebraska)
Brent Sipes (University of Hawaii)
Louise-Marie Dandurand (University of Idaho)

Brief Summary of Minutes

Project Number: W4186

Project Title: Variability, Adaptation, and Management of Nematodes Impacting Crop Production and Trade

State: Alabama Kathy Lawrence

Date: Nov. 14-15, 2021

Duration: October 1, 2021 to September 30, 2022

W4186 Meeting Participants:

Siddique, Shahid (University of California-Davis)

Gleason, Cynthia (Washington State University)

Kaloshian, Isgouhi (University of California-Riverside)

Lawrence, Kathy (Auburn University)

Melakeberhan, Haddish (Michigan State University)

Roberts, Phil (University of California-Riverside)

Groen, Niels (University of California-Riverside)

Beacham, Jacqueline (University of New Mexico)

Powers, Thomas (University of Nebraska)

Brent Sipes (University of Hawaii)

Louise-Marie Dandurand (University of Idaho)

Objective 1: Characterize genetic and biological variation in nematodes relevant to crop production and trade.

In California, Mi-1 is the only commercially available root-knot nematode resistance gene in tomato. Mi-1 confers resistance to three commonly occurring, damaging species of RKNs belonging to the MIG group (M. arenaria, M. incognita, and M. javanica) in tomato. In addition to nematodes, Mi-1 also confers resistance to some isolates of potato aphid (Macrosiphum euphorbiae) and whitefly (Bemisia tabaci). The increased reliance on Mi-1 due to the restricted use of nematicides has led to the emergence of resistance-breaking nematode isolates in tomato fields, posing a serious threat to tomato production. The objective of this work was to elucidate the genetic mechanisms and identifying genetic factors that allow nematodes to break Mi-1-mediated resistance and to investigate the potential fitness cost associated with breaking this resistance. We used two closely related strains of M. javanica, VW4 and VW5, which differ in their ability to parasitize tomato carrying Mi-1. VW4 cannot reproduce on tomato plants harboring Mi-1. By contrast, VW5 can reproduce on tomato carrying the Mi-1 gene. To assess whether the ability of VW5 to reproduce on Mi-containing tomato was associated with a loss of fitness, we inoculated tomato that does not carry Mi-1 with VW4 or VW5 and counted the number of eggs at 35 dai. We observed a significantly reduced egg number on plants inoculated with VW5 compared to VW4 indicating that fitness was reduced on tomato for the resistance breaking strain. To see if this loss of fitness extended to additional hosts, we compared egg production of VW4 and VW5 on cucumber [Cucumis sativus] and rice [Oryza sativa]). For both of these hosts, the fitness loss was greater than on tomato and very few eggs were produced. The quality of current published reference genome for M. javanica is not sufficient to allow resolution of the homeologous genomes. To address this limitation, we sequenced and assembled a high-quality reference genome for VW4 using a combination of HiFi, Hi-C, Iso-seq, and NanoPore sequencing. The scaffold numbers of our reference genome are close to those of the M. javanica chromosome indicating that several of the scaffolds are likely to span entire chromosomes. In addition, we have also sequenced the genome of VW5 using PacBio’s HiFi technology. Future work will focus on using a long-read aligner to map VW5 reads to the genome of VW4 and identify regions that differ between them.

States in the Northwestern region of the USA (WA, OR, ID) produce more than 50% of the potatoes in the country. Meloidogyne chitwoodi (also known as the Columbia root-knot nematode) is a major problem for potato producers in this region because the nematode infects tubers and causes blemishes. There is little tolerance for M. chitwoodi damage in the potato industry. To easily identify M. chitwoodi from field soils, the Gleason lab (WSU) developed a LAMP assay. The LAMP assay is a quick DNA-based detection method for potato-infecting root-knot nematodes (Zhang and Gleason 2019). The LAMP assay reliably detects two root-knot nematodes: M. chitwoodi and its close relative M. fallax. Because M. fallax is not found in the USA, a positive result in the LAMP assay would indicate the presence of M. chitwoodi. Nevertheless, a report of M. fallax in California turfgrass has raised the alarm about the potential introduction of this virulent, quarantine nematode into potato growing areas of the US (Nischwitz et al., 2013). Another related root-knot nematode called Meloidogyne minor was found in a Washington golf course (Nischwitz et al., 2013). Meloidogyne minor can also infect potatoes, although it has not been detected yet in US potato fields. In order to develop a single tube nematode assay that can distinguish M. chitwoodi, M. minor, and M. fallax, the Gleason lab has developed a molecular beacon assay. This PCR assay utilized the small genetic variation of the heat shock protein 90 (HSP90) gene to generate species specific probes. The molecular beacon assay can determine the species of a single nematode. This is the first single tube assay that can distinguish these three potato-infecting nematodes, two of which are of regulatory importance.

Within the species of M. chitwoodi, there are three major strains in the Pacific Northwest, and they are called Race 1, Race 2, and Roza. The different strains of M. chitwoodi are an on-going issue because all can infect potatoes. However, there are important differences between them. For example, Race 1 and Roza cannot reproduce on alfalfa, but can reproduce on carrot. Meanwhile, Race 2 can reproduce on alfalfa but not carrot. In addition, Roza is able to overcome the nematode resistance found in the potato breeding line PA99N82–4, but Race 1 and Race 2 cannot. Using the genetic variability between races, we developed PCR markers that can differentiate these three races. Using this PCR-based assay, the Gleason lab found that Race 1 and Roza were the predominant strains in Eastern Washington. This information has implications for future resistance breeding efforts.

In Idaho, they have recently initiated a project to determine the genetic diversity found in Globodera spp. so that we can target appropriate sources of resistance to encompass the genetic diversity found in Globodera spp. for development of resistant potatoes suitable for US growers and potato industry. The pathotype of 10 populations from Peru is being characterized through the use of a set of potato differential lines containing different resistance genes. One experiment has been terminated and is not being repeated. In addition, samples of Bolivian Globodera spp. are being genetically characterized. We also have set up one experiment in Bolivia to phenotype for resistance to 3 populations of Globodera (1 G. rostochiensis, and 2 G. pallida).

In Michigan they are working to understanding interactions of the northern root-knot (NRKN) and other plant-parasitic nematodes’ (PPN) parasitic variability (PV) in the same environment as beneficial (bacterivore, fungivore, predator and omnivore) nematodes in diverse cropping systems with varying degrees of soil health degradations is difficult. In this regard, the community analysis-based soil food web (SFW), fertilizer use efficiency (FUE), and integrated productivity efficiency (IPE) models are important decision-making tools for translating basic and complex science into practical application. The SFW model describes soil conditions of a given environment or in response to agricultural practice treatments by measuring changes in trophic and colonizer-persister (cp) groups (functional guilds) relative to food and reproduction against resistance to disturbance. With the SFW model, we established that NRKN was distributed in mineral and muck soils with disturbed and/or degraded soil health conditions and isolated 9 populations for PV test (Lartey et al., 2021). The degraded soils were characterized with low N. Knowing that there is link between NRKN presence and soil health conditions provides a foundation for formulating potential management strategies.

At University of Nebraska we have been developing metabarcoding methods and testing them against single nematode, Sanger sequencing methods for community diagnostics. This comparison has included cultivates, restored, and unplowed prairie land. For aquatic nematodes we have compared nematode communities from western Nebraska lakes with pH values ranging from 7.4 to 10.5. With regards to nematodes as environmental indicators, we are working on a set of soil samples that were affected by a major contamination event associated with an ethanol production facility that specialized in extracting ethanol from unsold, coated seeds in North America.

In New Mexico, the turf industry is an important partner in monitoring the movement of plant parasitic nematodes. Historically, root-knot nematodes in turf have only been isolated from locations in southern New Mexico. Species determination is currently underway for a root-knot nematode isolated from a commercial bentgrass turf sample taken from northern New Mexico. Of interest is if this is a new species to New Mexico or perhaps the beginnings of a northern expansion of our southern root-knot nematode as climate patterns shift. We continue to stay vigilant about Meloidogyne enterolobii, which has not yet been detected in New Mexico.

Objective 2: Determine nematode adaptation processes to hosts, agro-ecosystems and environments.

In Michigan, they tested 2 populations (8 and 13) from degraded and Population 2 from disturbed mineral soil and 3 populations each from disturbed (4, 6 and 10) and degraded (5, 14 and 16) muck soil, and revealed highest (Population13), medium (Population 8) and lowest (Populations 2, 4, 5, 6, 10, 14 and 15) PV (Lartey et al., 2022). In addition to expanding our understanding of why NRKN PV is higher in mineral than in muck soils, these results show that a) there is specificity within a category of soil health degradation and b) provide a foundation for formulating hypotheses that test deeper levels of interactions between nematode PV and the biophysicochemical environment.

Objective 3: Develop and assess nematode management strategies in agricultural production systems.

In Alabama, we determine the yield potential of the new M. incognita resistance variety PHY 360 W3FE and the R. reniformis resistant variety PHY 332 W3FE in nematode infested fields and if there was an additional benefit of adding nematicides to the resistant varieties. In 2020 and 2021, eight field trials were established in nematode infested fields and arranged as a RCBD with five replications. A Vydate^® C-LV and Fluazaindolizine mixture was applied at planting as an in-furrow spray across two resistant cultivars, PHY 360 W3FE and PHY 332 W3FE, and a susceptible cultivar, PHY 340 W3FE to further reduce nematode population levels. Field trials indicated that both M. incognita and R. reniformis eggs per gram of root were significantly (P > 0.05) lower on the resistant cotton cultivars, PHY 360 W3FE and PHY 332 W3FE, at 45 days after planting compared to the control PHY 340 W3FE without nematicides. M. incognita population levels were 84% lower on PHY 360 W3FE compared to PHY 340 W3FE and R. reniformis populations were 78% lower on the PHY 332 W3FE variety compared to PHY 340 W3FE. Nematode eggs per gram of root were further reduced after addition of Vydate^® C-LV and Fluazaindolizine to both susceptible and resistant varieties. In the M. incognita tests, PHY 360 W3FE with TRiO^{T M}+ Vydate^® C-LV + Fluazaindolizine at the high nematicide rate supported the greatest lint yield (1571 kg/ha), which was increased by 419 kg/ha over the lowest yielding treatment, PHY 340 W3FE + TRiO^TM (1152 kg/ha). The addition of the nematicides improved yield by 34 and 15 kg/ha for PHY 340 W3FE and PHY 360 W3FE, respectively. In the R. reniformis tests, PHY 332 W3FE with TRiO^TM + Vydate^® C-LV + Fluazaindolizine at the medium nematicide rate, supported the greatest yields (2137 kg/ha) which was increased by 1288 kg/ha over the lowest yielding treatment, PHY 340 W3FE. The addition of the nematicides improved yield by 572 and 293 kg/ha for PHY 340 W3FE and PHY 332 W3FE, respectively. Overall, the use of the resistant varieties significantly increase yield while limiting nematode population density; the addition of the nematicides also further enhanced yields of the PHY 360 W3FE and PHY 332 W3FE, nematode resistant varieties.

Further studies in Alabama integrated additional fertilizer and nematicide combinations to establish economical nematode management strategies while promoting cotton yield and profit. Field trials were run to evaluate fertilizer and nematicide combinations applied at the pinhead square (PHS) and first bloom (FB) plant growth stages to reduce nematode population density and promote plant growth and yield. Cost efficiency was evaluated based on profit from lint yields and chemical input costs. Data combined from 2019 and 2020 suggested a nematicide seed treatment (ST) ST + (NH₄)₂SO₄ + Vydate^® C-LV + Max-In^® Sulfur was the most effective in increasing seed cotton yields in the R. reniformis microplot trials. In R. reniformis field trials, a nematicide ST + (NH₄)₂SO₄ + Vydate^® C-LV at PHS supported the largest lint yield and profit per hectare at $1176. In M. incognita field trials, a nematicide ST + 28-0-0-5 + Vydate^® C-LV + Max-In^® Sulfur at PHS and FB supported the largest lint yields and profit per hectare at $784. These results suggest that combinations utilizing fertilizers and nematicides in addition to current fertility management show potential to promote yield and profit in R. reniformis and M. incognita infested cotton fields.

In Hawaii, management of plant-parasitic nematodes in pineapple typically involves fallow followed by fumigation with 1,3-dichloropropene (1,3-D) with unintended effects on soil health. Allyl isothiocyanate and crustacean meal to stimulate soil biological activity. A trial was established in a commercial field in collaboration with Dole Fruit Hawaii. CrabLife Flake (25% chitin) was applied at 0 or 785 kg/ha and incorporated. 1,3-D (300 l/ha) and allyl isothiocyanate (290 l/ha) were applied in the bed. An unfumigated, no CrabLife Flake area served as an untreated control. Soil samples were collected at pineapple planting, 3 months, and 6 months after planting. The ratio of fungi to bacteria in the at-planting samples was greatest in the untreated control and the fumigated plots receiving the CrabLife Flake. Plant-parasitic nematode populations were near 0/250 cm3 soil at planting and 3 months after planting. At 6 months after planting, the population of reniform nematodes remained low in the 1,3-D treated plots (133/250 cm3 soil) and increased in the untreated and allyl isothiocyanate treated plots (650 and 733/250 cm3 soil, respectively). Fungal feeding nematodes predominated over other free-living nematodes. Plant growth was not different among the treatments. The chitin amendment had positive effects on the fungi in the soil. Allyl isothiocyanate was effective in reducing plant-parasitic nematode populations for the first 3 months and may offer an alternative to improve soil health in pineapple production.

Hawaii also works with EPN’s on sweet potato weevil, Cylas formicarius, which severely damages sweet potato by burrowing through the tuber and depositing fecal pellets resulting in an unpalatable tuber to humans and livestock. Sweet potato yield losses can be up to 100%. Entomopathogenic nematodes (EPN) have potential use as an organic alternative to synthetic pesticides for the control of sweet potato weevil. Two local EPN isolates (Steinernema feltiae MG-14and Oscheius sp. Oa-12) were evaluated for efficacy against C. formicarius. Five larvae were placed in a petri dish lined with Whatman filter paper #1 (inoculation courts) and inoculated with either 100 Infective Juveniles (IJ) of either S. feltiae MG114 or Oschieus Oa-12 per larvae and exposed for 72 hours. Water served as a negative control. Infection courts were checked every 24 hours for larval mortality and dead larvae were transferred to White traps. EPN emergence was evaluated 21 days later. The experiment was replicated 6 times and repeated once. Larvae exposed to S. feltiae MG-14 had a mortality of 93% after 72 hours. Larvae exposed to Oscheius OA-12 had an average mortality of 43%. The negative control had a mortality of 10%. Emergence of IJ was observed from most larval cadavers from both treatments. Steinernema feltiae MG-14 inoculation resulted in greater mortality on the weevil larvae than Oscheius OA-12. The lack of emergence observed in some cadavers from inoculated plates may be due to natural death as reflected by the 10% mortality seen in the controls. Future research should examine the effectiveness the strains in field trials.

Currently, in Idaho, resistance to Globodera pallida in commercially relevant potato varieties for US growers does not exist. Through collaborations with breeders and plant geneticists, research has focused on breeding resistance into russet type potatoes for the US industry. Clones with partial resistance have been developed, and future efforts are focused on incorporating pyramiding different sources of resistance to achieve higher levels of resistance to G. pallida. We continue to screen the clones that are being developed to determine their resistance level to G. pallida. In addition to development of resistance through traditional breeding efforts, we have initiated a project to understand plant defenses of the trap crop, Solanum sisymbriifolium. We have found that exposure to different plant root exudates changes the behavior of G. pallida. Exposure to S. sisymbriifolium root exudates decreases mobility and infection rates of G. pallida. A transcriptome analysis revealed differences in expression of virulence and detoxification genes. Field trials have been established to develop a 3-year rotation plan for use in G. pallida infested fields. The rotation compares use of resistance or a trap crop in rotation with a susceptible potato variety and evaluates G. pallida population decline for each of the rotation plans. Our second-year rotation indicates that low levels of G. pallida reproduction occurred when a resistant potato was followed by a second year of a resistant potato, but no reproduction was observed when a resistant potato was planted in rotation with the trap crop S. sisymbriifolium. The third-year rotation will be planted to the susceptible potato Russet Burbank. We continue to evaluate potential nematicidal compounds isolated from the trap crop S. sisymbriifolium. High levels of solamargine have been extracted from roots of this trap crop. Fractions extracted from this plant have been found to be highly toxic to G. pallida, and reduce hatch, infection and reproduction of the nematode. Further fractionation and purification of this butanol and hexane fractions are being conducted and evaluated to determine their impact on G. pallida.

Michigan has developed an IPE model that a) expands the weighted abundance of functional guilds (WAFG) of the SFW, and integrates b) a soil health indicator (SHI) and c) the concepts of the FUE model to identify sustainability of soil health outcomes as: i) sustainable if SHI and WAFG increase (best case), ii) unsustainable if SHI and WAFG decrease (worst case) and iii) need additional measures to increase either SHI or WAFG to get to a sustainable outcome (Habteweld et al., 2022). This is the first model to quantitatively link SHI and WAFG to a specific soil health value and the only one of its kind. In addition, the IPE model provides a platform for integrating a broad range of SHIs in ways that will lead to identifying soil health from a single core of soil. The concepts of these models are being applied on on-farm studies (Kakaire et. al., 2022) accompanied by socio-cultural analysis of stakeholders (Widanagea et al., 2022) and actively promoted at national and international professional conferences (Melakeberhan and Habteweld, 2022a and b).

Maintaining the only nematode diagnostic lab for the state of New Mexico is a beneficial tool in staying informed about new introductions of plant parasitic nematodes relevant to commercial agriculture in our state. Potato tuber samples received from the Navajo Nation were recently confirmed to be infested with Meloidogyne chitwoodi. This nematode causes tuber defects that can significantly diminish the value of the crop and impinge on exportable destinations. Managing it is necessary. Research reported from Washington State University found that different isolates of M. chitwoodi differ in virulence and host range, which affects nematode management strategies. Efforts will continue to learn more about this New Mexico isolate and how/if it may vary from other isolates in the region. Root-knot nematodes are of economic significance in New Mexico agriculture, predominately we are concerned with Meloidogyne incogntia in the south and east where the bulk of our state agriculture is located. We do however have Meloidogyne hapla and M. chitwoodi in the northern agricultural fields of the state and M. partityla has been recovered from our pecan orchards.

Because access to irrigation water and arable land can be limiting factors in New Mexico, our annual row-crop fields tend are smaller on average. To be profitable on such limited acreage, farmers grow specialty crops that can withstand our climate, such as chile peppers and onion. With limited success in breeding M. incognita resistance into chile peppers, chile growers maintain a reliance on chemical control options to manage their persistent root-knot nematode populations. Several new chemistries have been developed in recent years that necessitate assessment in our region. A field study was conducted this year on a cayenne chile pepper crop grown in a sandy loam soil under buried drip irrigation with a history of severe root-knot nematode problems (Meloidogyne incognita). The objective was to assess yield and M. incognita population responses to different rates and timings of fluazaindolizine (Salibro^® ), fluopyram (Velum^® Prime) and fluensulfone (Nimitz^®). Data are still being analyzed, but average M. incognita J2 populations at the end of the season were 28% and 13% lower in plots that received single doses of 61.4 and 30.7 fl. oz. /acre Salibro^® at planting respectively, compared to untreated control plots. Comparative root gall rating results at harvest did not correlate with the soil M. incognita J2 data at harvest. While average gall rating scores in the 61.4 fl. oz. /acre Salibro^® treated plots were the lowest among treatments assessed (46% reduction compared to the untreated control); there were several other treatments that had much lower gall ratings than the single 30.7 fl. oz. /acre Salibro^® treatment that produced the successful soil J2 reduction. A double dose treatment of 30.7 fl. oz. /acre of Salibro^® (at planting and again 14 days later) and the Nimitz^®treated plots resulted in a 39% and 35% reduction in root galling compared to the untreated control. Despite suppressing M. incognita J2 populations and reducing host plant root galling, Salibro^® treatments when applied singly, regardless of the rate, did not effectively produce yields differing from the untreated control. Average fresh red chile yields were greatest in the 30.7 fl. oz. /acre of Salibro^® + Vydate^® treated plots with a 28% increase in yield compared to the untreated control followed by Nimitz^®, which resulted in a 22% increase in yield on average.

After ten years of chemical trials to control Meloidogyne incognita in vineyards across southern New Mexico with little success, an effort is underway to look closely into the soil population characteristics of M. incognita under typical vineyard management throughout the year. Temporal studies of Meloidogyne incognita on Vitis vinifera initiated in 2021 continued this year with the objective to determine if there is a seasonality or temperature correlation to M. incognita J2 populations in the soil that might help determine a most effective timing for chemical nematicide applications in vineyards. Soil and roots from multiple sites in a vineyard are being sampled biweekly. Soil temperatures are continuously recorded and will be used to determine the probability of a degree day reference for nematicide applications in vineyards. This study is unfunded and is being conducted on a commercial vineyard in collaboration with the grower. Data are communicated to growers at university sponsored field days and will ultimately be published.

Minutes Attachment:

W4186 meeting report 2022.docx

Accomplishments

Publications

Publications:   Book chapters:   Lawrence, Kathy S. 2021. Reniform nematode (Rotylenchulus reniformis) and its interactions with cotton (Gossypium hirsutum) Chapter 14: pages 94-100 in Integrated nematode management: state of the art and visions for the future. eds Richard Sikora, Johan Desaeger and Leendert Molendijk for CABI. DOI: 10.1079/9781789247541.0014   Refereed journal articles:   Acar, I., and B. Sipes. 2022. Enhancing the biological control potential of entomopathogenic nematodes - Protection from desiccation and UV radiation. Biological Control: 10.1016/j.biocontrol.2022.104874.   Anjam MS, Siddique S, Marhavy P. (2022). RNA isolation from nematode-induced feeding sites in Arabidopsis roots using Laser Capture Microdissection. Environmental Responses in Plants, pp 313-324.   Beckmann J.F., Dormitorio T., Oladipupo, S. O., Terra, M. T. B., Lawrence, K., Macklin, K.S., Hauck, R., Heterakis gallinarum and Histomonas meleagridis DNA Persists in Chicken Houses Years after Depopulation, Veterinary Parasitology (2021), DOI: <a href="https://doi.org/10.1016/j.vetpar.2021.109536">https://doi.org/10.1016/j.vetpar.2021.109536</a>   Borgmeier, A., Gattoni, K., Harris, T., Higgins, R., Mullin, P., Porazinska, D., Powers, K., Wedin, D. and Powers, T., 2022. Plectus of the Prairie: A Case Study of Taxonomic Resolution from a Nematode Biodiversity Survey. Journal of Nematology, 54(1).   Budhathoki,,S.,  B.S. Sipes, I. Shikano, R.Y. Myers, R. Manandhar, and K.-H. Wang. 2022. Integrating trap cropping and entomopathogenic nematode foliar sprays to manage diamondback moth and imported cabbage worm. Horticulturae 1073, https://doi.org/10.3390/ horticulturae8111073.   Divykriti C, Hasan MH, Matera C, Chitambo O, Mendy B, Mahlitz D, Naz AA, Szumski S, Janakowski S, Sobczak M, Mithöfer A, Kyndt T, Grundler FMW, Siddique S. (2021). Plant parasitic cyst nematodes redirect host indole metabolism via NADPH oxidase‐mediated ROS to promote infection. New Phytologist, 232: 318-331.   Gattoni, K., Gendron, E.M.S., Borgmeier, A., McQueen, J.P., Mullin, P.G., Powers, K., Powers, T.O. and Porazinska, D.L., 2022. Context dependent role of abiotic and biotic factors structuring nematode communities along two environmental gradients. Molecular   Habteweld, A., A. N. Kravchenko, P. S. Parwinder, and H. Melakeberhan (2022). A nematode community-based integrated productivity efficiency (IPE) model that identifies sustainable soil health outcomes: A case of compost application in carrot production. Soil Systems 6, 35. <a href="https://doi.org/10.3390/soilsystems6020035">https://doi.org/10.3390/soilsystems6020035</a>.    Hasan MS, Chopra D, Damm A, Koprivova A, Kopriva S, Meyer A, Mueller-Schuessele SJ, Grundler F, Siddique S. (2022). Glutathione contributes to plant defense against parasitic cyst nematodes. Molecular Plant Pathology, 23:1048-1059.   Hassan, Mohannad K., Kathy S. Lawrence, Edward J. Sikora, Mark R. Liles, and Joseph W. Kloepper. 2021. Enhanced biological control of root-knot nematode, Meloidogyne incognita, by combined inoculation of cotton or soybean seeds with a plant growth-promoting rhizobacterium and pectin-rich orange peel. Journal of Nematology 53:1-17. DOI: 10.21307/jofnem-2021-058.   Klink, Vincent P., Omar Darwish, Nadim W. Alkharouf & Katherine S. Lawrence. 2021. The impact of pRAP vectors on plant genetic transformation and pathogenesis studies including an analysis of BRI1-ASSOCIATED RECEPTOR KINASE 1 (BAK1)-mediated resistance. Journal of Plant Interactions, 16:1, 270-283, DOI: 10.1080/17429145.2021.1940328.   Kud J, Pillai SS, Raber G, Caplan A, Kuhl JC, Xiao F and Dandurand L-M (2022) Belowground Chemical Interactions: An Insight Into Host-Specific Behavior of Globodera spp. Hatched in Root Exudates From Potato and Its Wild Relative, Solanum sisymbriifolium. Front. Plant Sci. 12. <a href="https://doi.org/10.3389/fpls.2021.802622">https://doi.org/10.3389/fpls.2021.802622</a>    Land, Caroline J., Gary E. Vallad, Johan Desaeger, Edzard Van Santen, Joe Noling, and Kathy Lawrence. 2021. Supplemental fumigant placement improves root-knot and Fusarium wilt management for tomatoes produced on a raised bed, plasti-culture system in Florida’s Myakka fine sand. Plant Disease <a href="https://apsjournals.apsnet.org/doi/pdf/10.1094/PDIS-03-21-0543-RE">https://apsjournals.apsnet.org/doi/pdf/10.1094/PDIS-03-21-0543-RE</a> Lartey, I., A. Kravchenko, G. Bonito, and H. Melakeberhan (2022). Parasitic variability of Meloidogyne hapla relative to soil groups and soil health conditions. Nematology 24: DOI 10.1163/15685411-bja10185.   Lawaju BR, Groover W, Kelton J, Conner K, Sikora E, Lawrence KS. 2021. First report of Meloidogyne incognita infecting Cannabis sativa in Alabama. Journal of Nematology. 2021 May 1;53:e2021-52. doi: 10.21307/jofnem-2021-052. PMID: 33959722; PMCID: PMC8098102.   Marquez, J., R. Paudel, B.S. Sipes, and K.-H. Wang. 2022. Successional effects of no-till cover cropping with black oat (Avena strigosa) vs. soil solarization on soil health in a tropical Oxisol. Horticulturae 8: 527.   Matczyszyn, J.N., Harris, T., Powers, K., Everhart, S.E. and Powers, T.O., 2022. Ecological and morphological differentiation among COI haplotype groups in the plant parasitic nematode species. Journal of Nematology, 54(1), pp.1-24.   Nyaku, S. T., V. R. Sripathi, K. Lawrence, and G. Sharma. 2021. Characterizing Repeats in Two Whole-Genome Amplification Methods in the Reniform Nematode Genome. International Journal of Genomics. <a href="https://doi.org/10.1155/2021/5532885">https://doi.org/10.1155/2021/5532885</a>.    Popova, I., B. Sell, S. S. Pillai, J. C. Kuhl, L. M. Dandurand. 2022. High-performance liquid chromatography-mass spectrometry analysis of glycoalkaloids from underexploited Solanum species and their acetylcholinesterase inhibition activity. Plants 11:269.   Rutter, W.R., Franco, J., Gleason, C. (2022) “Rooting out the mechanisms of plant-nematode interactions.” Annual Review of Phytopathology 2022 60:1.   Sanchez, WinDi, David Shapiro, Geoff Williams, and Kathy Lawrence. 2021. Entomopathogenic nematode management of small hive beetles (Aethina tumida) in three native Alabama soils under low moisture conditions. Journal of Nematology 53:1-14. DOI: 10.21307/jofnem-2021-063.   Siddique S, Coomer A, Baum T, Williamson VM (2022). Recognition and response in plant–nematode interactions. Annual Review of Phytopathology, 26;60:143-162.   Siddique S, Radakovic Z, Hiltl C, Pellegrin C, Baum T, Beasley H, Bent A, Chitambo O, Chopra D, Danchin E, Grenier E, Habash S, Hasan M.S, Helder J, Hewezi T, Holbein J, Holterman M, Janakowski S, Koutsovoulos G, Kranse O, Lozano-Torres J, Maier T, Masonbrink R, Mendy B, Reimer E, Sobczak S, Sonawala U, Sterken M, Thorpe P, Steenbrugge JV, Zahid N, Grundler FMW, Eves-van den Akker S. 2022. The genome and lifestage-specific transcriptomes of a plant-parasitic nematode and its host reveal susceptibility genes involved in trans-kingdom synthesis of vitamin B5. Nature Communications, 13: 6190.   Waisen, P., Z. Cheng, B.S. Sipes, and K.-H. Wang. 2022. Biofumigation effects of brassicaceous cover crops on soil health in cucurbit agroecosystems. Pedosphere 32:521-531. <a href="https://doi.org/10.1016/S1002-0160(21)60054-1">https://doi.org/10.1016/S1002-0160(21)60054-1</a>.   Widanagea, R., C. Chan, Y-P. Tsanga, B. S. Sipes, H. Melakeberhan, A. Sanchez, A. Mejiac (2022). Enhancing technical efficiency and economic welfare: A case study of smallholder potato farming in the Western Highlands of Guatemala. Economia agro-alimentare/Food Economy 24: doi: 10.3280/ecag2022oa13227.   Yimer HZ, Dee Dee L, Coomer AB, Ercoli MF, Vieira P, Williamson VM, Ronald PC, Siddique S. 2022. Root-knot nematodes produce functional mimics of tyrosine-sulfated plant peptides. (2022). bioRxiv, doi:10.1101/2022.10.13.511487.     Peer reviewed articles and proceedings:   Faske, Travis R., Thomas W. Allen, Zane J. Grabau, Jiahuai Hu, Robert C. Kemerait, Kathy S. Lawrence, Hillary L. Mehl, John Mueller, Paul Price, Lindsey D. Thiessen, and Terry A Wheeler. 2020. Beltwide Nematode Research and Education Committee Report on Field Performance of Seed and Soil-Applied Nematicides, 2019. Proceedings of the 2020 Beltwide Cotton Conference Vol. 1: 192-196. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm</a>   Gordon, Kara,  Kathy S. Lawrence, Drew Schrimsher and Brad Meyer. 2020. A Cost-Effective Prescription Management Strategy Utilizing Fertilizers and Nematicides to Combat Yield Losses from Rotylenchulus reniformis on Cotton. Proceedings of the 2020 Beltwide Cotton Conference Vol. 1: 169-171. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm</a>   Lawaju, Bisho Ram and Kathy S. Lawrence. 2020. Evaluation of Salibro as a New Nematicide for Cotton Production Systems.  Proceedings of the 2020 Beltwide Cotton Conference Vol. 1: 458-463. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm</a>   Lawrence, Kathy S., Austin Hagan, Randy Norton, Jiahuai Hu, Travis R. Faske, Robert B Hutmacher, John Muller, Ian Small, Zane J. Grabau, Robert C. Kemerait, Doug Jardine, Paul Price, Thomas W. Allen, Calvin D Meeks, John Idowu, Lindsey D. Thiessen, Seth A. Byrd, Jerry Goodson, Heather Kelly, Terry Wheeler, Thomas Isakeit and Hillary L. Mehl. 2020. Cotton Disease Loss Estimate Committee Report, 2020.         Proceedings of the 2020 Beltwide Cotton Conference Vol. 1: 117-119. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm</a>   Schrimsher, Drew, Brad Meyer, Kathy S. Lawrence, Bisho Ram Lawaju, Marina Rondon, Will Groover, David R Dyer and Kara Gordon. 2020. Cotton Cultivar Response to CLRDV as Influenced By Planting Dates.  Proceedings of the 2020 Beltwide Cotton Conference Vol. 1: 388-391. National Cotton Council of America, Memphis, TN. <a href="http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm">http://www.cotton.org/beltwide/proceedings/2005-2020/index.htm</a>             Turner, A. K., Lawrence, K. S., Gordon, K., Dyer, D., Lawaju, B., Rondon, M., Norris, C. 2020. Management strategies utilizing seed treatments to combat yield loss from reniform nematode on cotton. Report No. 15:N010. The American Phytopathological Society, St. Paul, MN. https://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2021/N010.pdf    Turner, A. K., Lawrence, K. S., Gordon, K., Dyer, D., Lawaju, B., Rondon, M., Norris, C. 2020. Soybean seed treatment combinations for decreasing reniform nematode population density in North Alabama. Report No.  15:N009. The American Phytopathological Society, St. Paul, MN. https://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2021/N009.pdf    Turner, A. K., Lawrence, K. S., Gordon, K., Dyer, D., Lawaju, B., Rondon, M., Richburg, J., Norris, C. 2020. Nematicide and cotton variety combinations for decreasing reniform nematode populations in North Alabama. Report No.15:N016. The American Phytopathological Society, St. Paul, MN.  https://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2021/N016.pdf    Turner, A. K., Lawrence, K. S., Gordon, K., Dyer, D., Lawaju, B., Rondon, M., Norris, C. 2020. Nematicide and cotton variety combinations for decreasing root-knot nematode populations in Central Alabama. Report No. 15:N017. The American Phytopathological Society, St. Paul, MN. https://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2021/N017.pdf    Abstracts    Kakaire, S., A. Sanchez, A. Sacbaja, C. Chan, B.S. Sipes, and H. Melakeberhan (2022). Adopting integrated nematode-soil health management in smallholder potato farmers in the Highlands of Guatemala. 7th International Congress of Nematology, Nice, France.    Lartey, I., A. Kravchenko, G. Bonito, and H. Melakeberhan (2022). Parasitic variability of Meloidogyne hapla relative soil groups and soil health conditions. 61st Annual Meeting of the Society of Nematologists. Anchorage, Alaska.

Impact Statements

Allyl isothiocyanate holds promise as a preplant treatment for management of reniform nematode.