Brief Summary of Minutes of Annual Meeting

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

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.

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. https://doi.org/10.1094/PDIS-09-18-1550-PDN

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. https://doi.org/10.1094/PDIS-09-18-1550-PDN

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.  doi: 10.3389/fpls.2017.01979

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. https://doi.org/10.1111/jph.12712

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

2018. 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.

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. http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N010.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N011.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N013.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N014.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N019.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N020.pdf

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. http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm

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. http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N040.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N041.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N004.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N005.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N006.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N008.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N009.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N007.pdf

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.  http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N021.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N022.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N023.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N024.pdf

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. http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N025.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/ST002.pdf

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. http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm

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 17^th 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. http://www.cotton.org/beltwide/proceedings/2005-2018/index.htm

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N026.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N027.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N028.pdf

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.  http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N029.pdf

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.  http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N032.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N033.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N034.pdf

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. http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2018/N035.pdf