Brief Summary of Minutes of Annual Meeting

OSU administrators provided an interesting update on their school and programs. Each state proceeded to report on project objectives. During the business meeting Cindy Gleason was elected Vice Chair and Inga Zasada was elected Secretary. The 2018 meeting will be held in Hawaii in early November.

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

Ditylenchus dipsaci was initially confirmed in New Mexico in 2015. The confirmation triggered a systematic survey of commercial onion fields to detect additional infested sites. Putative Ditylenchus spp. were recovered at low numbers (< 60/100 cm³ soil) from 21 fields. Multiple single-nematode specimens were collected from each infested field and identified using direct sequencing of 18S and ITS regions of the rRNA genes. When identified using only 18S sequence data, 60% of individuals were identified as D. dipsaci (99% similarity), 27% as D. destructor (98% similarity), with the remainder somewhat resembling D. destructor (92-94% similarity) – both of which are species of international regulatory concern that would prevent export to Canada (primary foreign market for NM onions).  When direct sequencing data was expanded to include the ITS-1 region, none of the individuals were identified as D. dipsaci or D. destructor.  Species with the greatest similarity to those recovered included D. arachis (92% similarity) and D. persicus (90% similarity), which are not currently species of regulatory concern.  These result show the importance of using combined 18S and ITS1 rRNA sequences to identify Ditylenchus species for regulatory purposes.  

 Species identification of Meloidogyne spp. (root-knot nematode, RKN) is an important tool to offer growers because it is beneficial for planning and implementing a crop rotation to reduce the impact of these yield-limiting nematodes. Morphological measurements, differential-host test, and molecular analysis were evaluated for their ability to quickly and accurately identify RKN species. Seventy five samples from 14 counties in Alabama were collected from cotton, soybean, corn, peanut, sweet potato, squash, pepper, kiwi, turmeric, and turf. Primers used for PCR include those that identify commonly found RKN species: M. incognita, M. arenaria, M. javanica, M. hapla, M. fallax, M. chitwoodi, and M. enterolobii. Of these samples, 73 were identified as M. incognita (97%), and two were identified as M. arenaria (3%). These species were identified through the differential-host test and PCR using primer sets IncK-14F/IncK-14R (M. incognita) and Far/Rar (M. arenaria). Overall, M. incognita is the most prevalent species of root-knot nematode that has been found on cropping systems in Alabama during this project.

Cytochrome Oxidase C Subunit 1 (COI) barcoding datasets of major groups of plant- and insect-parasitic nematodes have been added. Recent additions include: Heterodera specimens reproducing on alfalfa  from two states; Meloidogyne hapla on alfalfa in Nebraska; Aphelenchoides besseyi from Louisiana; Heterorhabditis/Steinernema: addition of native isolates from central Nebraska. Criconematoidea: two new species have been described and new host reproduction information is available for Mesocriconema nebraskense; Pratylenchus: isolates from across the Great Plains region are being added with 6 major haplotype groups primarily found in corn and wheat. There is still uncertainty about Brazilian A.besseyi reproducing on forage grasses. There are 5 described species on the Aphelenchoides tree and multiple groups of unknown species.

The origin of the reniform nematode, Rotylenchulus reniformis, on Oahu and its spread across the state is unknown. Microsatellite markers (SSR) and pedigree analysis provided an understanding of the dispersal of this nemaotde. The SSR markers RR 2-5, RR2-6, RR3-3, RR3-8, RR4-1, RR4-4, RR4-5, RR 1-5 and RR2, RR5 displayed variation within loci. The RR2-5 marker produced 8% double bands and 72% single bands. Similar double bands were observed in RR2-6 (8% double bands, 56% single band, and 36% no band). RR3-3 produced 100% single bands whereas RR3-8 and RR4-1 had 40% single bands and 60% no bands.  RR4-4 gave 54% single bands and 46% no bands. RR1-5, RR2, RR 4-5 and RR5 did not amplify any DNA in the Oahu population. Theses SSR markers have detected differences within the Oahu population and differences among the Oahu population and other populations. The variation detected may indicate that the Oahu population is distinct compared to isolates tested by Leach et al.

Twelve oak species were evaluated as hosts of the pecan root-knot nematode (Meloidogyne partityla). Cork and Pin oak allowed the production of galls and egg masses, while Holly, Tabor, and burr Oaks produced galls only. English Walnut (Juglans regia) also allowed production of galls and egg masses. Over 200 soybean Plant Introductions reported to have a high level of Soybean Cyst Nematode (SCN) resistance and 204 with moderate SCN for resistance were evaluated with the reniform nematode (Rotylenchulus reniformis). Of those with a high level of resistance 44 PIs have resistance to reniform nematodes. For those with moderate resistance, 5 PIs showed reniform reproduction not different than than the resistant standard “Hartwig.” Correlation of reproduction and phenotypes could be useful in identifying soybean PIs with resistance to both SCN and reniform nematodes. Over 400 samples have been identified to species with M. incognita the most common root-knot nematode in Arkansas.

Understanding parasitic variability in the northern root-knot nematode (NRKN, Meloidogyne hapla) and soybean cyst nematode (Heterodera glycines, SCN) and their adaptation in a given soil biophysical environment are among the long term studies in our program. NRKN is among the most problematic plant-parasitic nematodes in vegetable production in the northern hemisphere where there are no commercially available resistant cultivars and its parasitic variability is a major challenge. Establishing NRKN’s distribution and adaptation in Michigan vegetable production systems relative to soil types, other plant-parasitic and beneficial nematodes, and the environment they inhabit is one of the least known areas. Testing the fitness of different populations of NRKN against Midwest adapted potato, celery, and carrot cultivars, and the effect of soil biophysiochemical conditions on NRKN populations provided a proof-of-concept for location-specific approaches to managing parasitic variability in production systems. These studies led to on-going studies to demonstrate the interaction of NRKN population in different soil types and ecoregions in Michigan and emerging fresh market carrot cultivars with resistance to NRKN. We are rebuilding our cultures of both nematodes collected from different locations within Michigan soils. The NRKN cultures are being re-tested against emerging NRKN-resistant fresh market carrot cultivars. Another important line of investigation is understanding how, if any, NRKN populations’ parasitic behavior may be directly or indirectly influenced by biophysiochemical changes in their environment. We will be using a combination of the soil food web (SFWM) and fertilizer use efficiency (FUE) models to characterize the outcomes that lead to location-specific conditions in the specific soil/farm environments in which NRKN populations exist. The SFWM identifies the agronomic practices driven biophysiochemical outcomes from worst to best case scenarios for soil nutrient cycling, agroecosystem suitability and overall soil health.  The FUE model separates nutrient deficiency and toxicity and measures integrated efficiency of the agronomic practices on suppressing harmful organisms while improving beneficial organisms, nutrient cycling and overall soil health.

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

Mesocriconema nebraskense, an endemic species, is causing economic damage to introduced bent grass (Agrostis stolonifera) in golfcourse greens in New Mexico. Population densities ranged from 670-14,964/100 cm³ soil.  Suppression of nematodes to < 400/100 cm³ soil resulted in bent grass recovery. The nematode species was confirmed by two W3186 project members. The species is broadly distributed throughout native grasslands in central North America that contain gramineaceous plants also common to the ‘southern desert basin, plains, and mountains grasslands’ plant community present in several study sites in  NM. Knowledge of the susceptibility of perennial xeriscape plants to Meloidogyne incognita will provide valuable information regarding the possible presence of resistance genes within the host population.  The reproductive capacity, expressed as  a reproductive factor (RF), for each species will be used to rate the perennials as “good”, “poor”, or “non-hosts” and results shared with nurseries, landscape professionals, and home owners for consideration when selecting plants for use in root-knot nematode infested soil.

Common turmeric (Curcuma longa L.), a spice crop native to India, is a niche crop for Alabama. Plants exhibit chlorosis, stunting, and marginal leaf necrosis. Symptomatic plants were collected and root systems exhibited numerous galls, typical of Meloidogyne infection. Nematode eggs were extracted and identified as M. incognita. Meloidogyne incognita-inoculated turmeric selections CL2 and CL7 exhibited significantly reduced average plant height, shoot fresh weight, and root fresh weight with the measurements being 31%, 50%, and 26% of those of the control, respectively. Inoculated selection CL3 did not present significant differences with the control in terms of plant development. Final nematode population densities on CL2, CL3, and CL7 ranged from 19-319 eggs per gram of root, 1-2527, and 41-4703 eggs per gram of root, respectively. Reproductive factor (RF), defined as the final nematode population density divided by the initial inoculum density, was calculated to be 0.6, 4.1, and 2.1 for CL2, CL3, and CL7, respectively. Consequently, turmeric selections CL3 and CL7 were susceptible to the nematode, as their RF values were greater than 1. Turmeric selection CL2, on the other hand, was somewhat resistant to the nematode as its RF value was less than 1. To our knowledge, this is the first report of Meloidogyne incognita infecting Curcuma longa in the United States. Because M. incognita has been recorded in 46 out of Alabama’s 67 counties, potential growers of turmeric should consider nematode management when developing a holistic integrated pest management plan. As shown in greenhouse testing, turmeric selections differ in host suitability to M. incognita race 3. Variety selection will prove an important step to successful turmeric production in the state of Alabama.

A harpin elicitor induces the expression of a coiled-coil nucleotide binding leucine rich repeat (CC-NB-LRR) defense signaling gene and other genes functioning during defense to parasitic nematodes. The bacterial effector harpin induces the transcription of the Arabidopsis thaliana (thale cress) NON-RACE SPECIFIC DISEASE RESISTANCE 1/HARPIN INDUCED1 (NDR1/HIN1) coiled-coil nucleotide binding leucine rich repeat (CC-NB-LRR) defense signaling gene. In Glycine max (soybean), Gm-NDR1-1 transcripts have been detected within root cells undergoing a natural resistance reaction to parasitism by the syncytium-forming nematode Heterodera glycines (soybean cyst nematode [SCN]), suggesting that Gm-NDR1-1 functions in the defense response. Expressing Gm-NDR1-1 in Gossypium hirsutum (cotton) leads to resistance to Meloidogyne incognita (root knot nematode [RKN]) parasitism. In experiments presented here, the heterologous expression of Gm-NDR1-1 in G. hirsutum impairs Rotylenchulus reniformis (reniform nematode) parasitism. These results are consistent with the hypothesis that Gm-NDR1-1 expression functions broadly in generating a defense response. To examine a possible relationship with harpin, we evaluated G. max plants topically treated with harpin for induction of the transcription of Gm-NDR1-1. The result indicates the topical treatment of plants with harpin, itself, may lead to impaired nematode parasitism. Topical harpin treatments are shown to impair G. max parasitism by H. glycines, M. incognita and R. reniformis and G. hirsutum parasitism by M. incognita and R. reniformis. How harpin could function in defense has been examined in experiments showing it also induces transcription of G. max homologs of the proven defense genes ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1), TGA2, galactinol synthase, reticuline oxidase, xyloglucan endotransglycosylase/hydrolase, alpha soluble N-ethylmaleimide-sensitive fusion protein (-SNAP) and serine hydroxymethyltransferase (SHMT). In contrast, other defense genes are not directly transcriptionally activated by harpin. The results indicate harpin induces pathogen associated molecular pattern (PAMP) triggered immunity (PTI) and effector-triggered immunity (ETI) defense processes in the root, activating defense to parasitic nematodes. RNA has been isolated from Glycine max (soybean) root cells undergoing the process of defense to Heterodera glycines (soybean cyst nematode). The RNA has been used in gene expression analyses. The procedure has led to the identification of candidate resistance genes. A gene testing platform has been developed to functionally test these genes. The procedure has examined hundreds of genes with some functioning effectively in defense. The analysis has demonstrated the importance of various cellular processes to defense and has identified genes that previously had no known role in defense. RNA has been isolated from Glycine max (soybean) root cells undergoing the process of defense to a root pathogen. The RNA has been used in gene expression analyses, leading to the identification of candidate resistance genes. A gene testing platform has been developed to functionally test these genes with the aim of determining if the genes function during the process of defense. The procedure has examined hundreds of genes with some functioning effectively in defense. The analysis has demonstrated the importance of various cellular processes to defense and has identified genes that previously had no known role in defense.

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

The project team members are evaluating multiple tactics to manage population densities of nematodes in crops and the landscape. Approaches include the evaluation of chemicals and biological agents.

The potential of 662 plant growth-promoting rhizobacteria (PGPR) strains to kill Meloidogyne incognita J2 in vitro and to manage M. incognita in greenhouse, microplot, and field trials was tested. Mortality of M. incognita by the PGPR strains ranged from 0 to 100% with an average of 39%. Among the PGPR strains examined, 212 of 662 strains (or 33%) caused significantly greater mortality percent of M. incognita J2 than the untreated control. Bacillus spp. caused  greater mortality percentage when compared with the other genera of PGPR. In subsequent trials, B. velezensis strain Bve2 reduced M. incognita eggs per gram of cotton root in the greenhouse trials at 45 days after planting (DAP) similarly to the commercial standards Abamectin and Clothianidin plus B. firmus I-1582. Bacillus mojavensis strain Bmo3, B. velezensis strain Bve2, B. subtilis subsp. subtilis strain Bsssu3, and the Mixture 2 (Abamectin + Bve2 + B. altitudinis strain Bal13) suppressed M. incognita eggs per gram of root in the microplot at 45 DAP. Bacillus velezensis strains Bve2 and Bve12 also increased seed-cotton yield in the microplot and field trials. Overall, results indicate that B. velezensis strains Bve2 and Bve12, B. mojavensis strain Bmo3, and Mixture 2 have potential to reduce M. incognita population density and to enhance growth of cotton when applied as in-furrow sprays at planting.    

Biological control is also being evaluated for management of H. glycines. The efficacy of the biological products ALB EXP Bacteria 1, 2, and 3, Burkholderia sp. alone and in combination with bacterial metabolites Saponin, and Harpin, a standard Abamectin and an untreated control were evaluated. All seeds were treated by Albaugh, LLC. Treated seeds were planted and inoculated with H. glycines (2500 eggs). At harvest, no negative effects were recorded from any treatment on soybean growth.  Seed treatments significantly reduced eggs and cysts of H. glycines compared with the untreated control. Seed treatments were similar in efficacy to the standard, Abamectin. H. glycines J2 populations were significantly lower in the seed treatments compared with the control except in treatments ALB EXP Bacteria 1 and 2.  When two systemic acquired resistance products were added to Burkholderia sp., both cyst and egg numbers were lower compared to Burkholderia alone.

Agricultural chemical companies are developing products for nematode control in row and vegetable crops. Efficacy studies have been conducted to determine their effect on nematode infestations of field crops. Many are still in their early developmental stages therefore only numbers or codes are available for some of the listed products.

In microplot studies, on pinto bean receiving 5.0 and 7.0 pt/acre fluensulfone M. incognita populations were 39% and 20% lower respectively compared to untreated control plots or those treated with 3.5 pt/acre fluensulfone.  Management of M. incognita in direct-seeded chile pepper (Capsicum annuum cv Sandia) to fluensulfone broadcast, banded, and to 1,3-dichloropropene under furrow irrigation is being evaluated.  Management of M. incognita in grape (Pinot Grigio scion on ‘Freedom’ rootstock) with two rates of fluensulfone and spirotetramat shows numbers of second-stage juveniles (J2) were 84%, 74%, and 53% less than untreated plots in response to treatment with 8 oz/acre spirotetramat, 3.5 pt/ acre and 5.0 pt/acre fluensulfone, respectively.  Average berry yields were 30% greater in all treated plots compared to the untreated controls.

Little to no tolerance for infection of potato tubers by Columbia root-knot nematodes (CRKN, Meloidogyne chitwoodi) exists. Strategies that reduce reproduction by CRKN that could either result in sufficient control alone or reduce population densities are being investigated including MeloCon, Purpureocillium lilacinus strain 251; Bio Blend containing Agrothrive fermented fish product; Soil Medic; Sobec; and Soyaplex; Hyper Galaxy, a consortia of plant growth-promoting rhizobacteria (PGPR) including Azospirillum brazilense, Azotobacter chroococcum, Bacillus azotofixans, Pseudomonas fluorescens, and Pseudomonas putida; and BioFit N, containing Azotobacter chroccocum, Bacillus subtillis, Bacillus megaterium, Bacillus mycoides, and Trichoderma harzianum. CRKN host (Barley ‘C-69’) and nonhost (radish ‘Terra Nova’) were treated with MeloCon (2 lb/acre) or BioFit N (1 lb/acre). Total eggs and J2/pot in barley were 42,287, 39,181, and 28,850 and in radish were 35, 0 and 0 for pots that were untreated or treated with MeloCon or BioFit N, respectively. After harvest, a ‘Stevens’ wheat (excellent host) seedling was transplanted into the remaining soil from each pot to assess for any residual suppression of CRKN from the different treatments. Eggs and J2/pot reached high levels in all pots that had been planted to barley (63,679, 29,287, and 46,165) whereas the numbers of CRKN recovered from pots that had been initially planted to radish were extremely low (134, 106, and 5/pot) from pots that were untreated or treated with MeloCon or BioFit N, respectively. Fresh shoot biomass of ‘Stevens’ wheat, ‘C-69’ barley or ‘Sordan 79’ sudangrass at a rate of 15 tons/acre was mixed into soil containing 5,000 CRKN eggs and then either untreated or treated with MeloCon (4 lb/acres). CRKN reproduction factors were calculated. None of the biomass amendments had any effect on CRKN reproduction compared to that in the unamended pots. MeloCon significantly reduced reproduction in the unamended pots but had no effect on pots that had been amended with plant biomass. Soil infested with CRKN was treated with MeloCon at simulated in-furrow rates of 2, 4, or 6 lb/acre and received no further treatment for the rest of the trial. Another group of pots was treated with Bio Blend at 10 gal/acre, Hyper Galaxy at 4 oz/acre, or BioFit N at 1 lb/acre applied as a simulated in-furrow at planting and as chemigation applications in ½ in. water at 30 and 60 days. An additional group of pots received MeloCon at 2 lb/acre plus BioBlend, Hyper Galaxy or BioFit N at 30 and 60 days. The 2 lb rate of MeloCon had a significantly lower RF than in the untreated pots and the 4 lb rate had a significantly lower RF than in the untreated pots or the pots that received the 2 lb/acre rate. The 6 lb rate had a significantly lower RF than the untreated control but was not different than either the 2 or 4 lb rates. Pots treated with Bio Blend, Hyper Galaxy and BioFit N alone all had significantly lower RF values than the untreated control. Hyper Galaxy had the lowest RF value which was significantly less than that for BioFit N. None of the combination treatments of 2 lb MeloCon at planting  plus Bio Blend, Hyper Galaxy, or BioFit N at 30 and 60 days had an RF value that was different from that of the 2 lb/acre MeloCon treatment alone. Furthermore, the combination treatments of MeloCon plus Bio Blend and MeloCon plus Hyper Galaxy had higher RF values than the corresponding treatment without MeloCon.

Sixty six soybean breeder lines were tested for reniform resistance. The lines represent breeders from Arkansas, Clemson, Georgia, and Missouri. Of these 66 lines, two each from Clemson and Georgia, ten of Missouri, and none from Arkansas showed reniform nematode resistance: reproduction of the nematode on these lines did not exceed its reproduction on the resistant check “Hartwig.” These 14 lines may be useful in breeding for reniform resistance in commercial lines.

Journal Articles:

1. Aljaafri, W.A.R., McNeece, B.T., Lawaju, B.R., Sharma, K., Niruala, P.M., Pant, S.R., Long, D.H., Lawrence, K.S., Lawrence, G.W., Klink, V.P. 2017. A harpin elicitor induces the expression of a coiled-coil nucleotide binding leucine rich repeat (CC-NB-LRR) defense signaling gene and others functioning during defense to parasitic nematodes. Plant Physiology and Biochemistry 121:161-175.
2. Asiedu, O., C. K. Kwoseh, H. Melakeberhan, and T. Adjeigyapong.2017. Nematode distribution in cultivated and undisturbed soils of Guinea Savannah and Semi-deciduous Forest zones of Ghana. Geoscience Frontiers. https://doi.org/10.1016/j.gsf.2017.07.010.
3. Crutcher, F. K., L. S. Puckhaber, R. K. Stipanovic, A. A. Bell, R. L. Nichols, K. S. Lawrence, J. Liu. 2017 Microbial resistance mechanisms to the antibiotic and phytotoxin Fusaric acid. Journal of Chemical Ecology October 6, 2017. DOI 10.1007/s10886-017-0889-x
4. Dodge, D., K. S. Lawrence, W. Groover, S. Till, D. Dyer, and M. Hall. 2017. Soybean variety yield comparison with and without Abamectin for management of Rotylenchulus reniformis in Belle Mina Alabama, 2016. Report No. 11:N017. DOI: 10.1094/PDMR11. The American Phytopathological Society, St. Paul, MN. http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N017.pdf
5. Dodge, D., K. S. Lawrence, W. Groover, S. Till, D. Dyer, and M. Hall. 2017. Soybean variety yield comparison with and without Abamectin for management of root-knot nematode in Fairhope Alabama, 2016. Report No. 11:N018. DOI: 10.1094/PDMR11. The American Phytopathological Society, St. Paul, MN. http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N018.pdf
6. Dodge, D., K. S. Lawrence, W. Groover, S. Till, D. Dyer, and M. Hall. 2017. Soybean variety yield comparison with and without Abamectin for management of root-knot nematode in Brewton Alabama, 2016. Report No. 11:N019. DOI: 10.1094/PDMR11. The American Phytopathological Society, St. Paul, MN. http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N019.pdf
7. Dodge, D., K. S. Lawrence, W. Groover, S. Till, D. Dyer, and M. Hall. 2017. Soybean variety yield comparison with and without Abamectin for management of root-knot nematode in Tallassee Alabama, 2016. Report No. 11:N020. DOI: 10.1094/PDMR11.The American Phytopathological Society, St. Paul, MN. http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N020.pdf
8. Dodge, D., K. S. Lawrence, E. Sikora and D. P. Delaney. 2017. Evaluation of Soybean Varieties with Avicta for Control of Rotylenchulus Reniformis. Proceedings of the 2017 Beltwide Cotton Conference Vol. 1: 198-200. National Cotton Council of America, Memphis, TN. http://cotton.org/beltwide/proceedings/2010-2017/index.htm
9. Dyer, D., K. S. Lawrence, S. Till, D. Dodge, W. Groover, N. Xiang, and M. Hall. 2017. A potential new biological nematicide for reniform management in north Alabama, 2016. Report No. 11:N012. DOI: 10.1094/PDMR11. The American Phytopathological Society, St. Paul, MN. http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N012.pdf
10. Dyer, D., K. S. Lawrence, S. Till, D. Dodge, W. Groover, N. Xiang, and M. Hall. 2017. A potential new biological nematicide for root-knot management in Alabama, 2016. Report No. 11:N013. DOI: 10.1094/PDMR11. The American Phytopathological Society, St. Paul, MN. http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N013.pdf
11. Dyer, D., N. Xiang, and K. S. Lawrence. 2017. First report of Catenaria anguillulae infecting Rotylenchulus reniformis and Heterodera glycines in Alabama. Plant Disease. 101(8):1547. https://doi.org/10.1094/PDIS-03-17-0366-PDN.
12. Dyer, D., K. S. Lawrence and D. Long. 2017. A Potential New Biological Nematicide for Meloidogyne Incognita and Rotylenchulus Reniformis Management on Cotton in Alabama. Proceedings of the 2017 Beltwide Cotton Conference Vol. 1: 208-210. National Cotton Council of America, Memphis, TN. http://cotton.org/beltwide/proceedings/2010-2017/index.htm
13. A. Ahmed, 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 
14. A. Ahmed, B.S. Sipes, and A.M. Alvarez. 2016. Natural products to control postharvest gray mold of tomato fruit - possible mechanisms. Journal of Plant Pathology and Microbiology 7:1-7. DOI: 10.4172/2157-7471.1000367.
15. French, J.M., J. Beacham, A. Garcia, N.P. Goldberg, S.H. Thomas, and S.F. Hanson.   First Report of Stem and Bulb Nematode Ditylenchus dipsaci on Garlic in New Mexico.  Plant Health Progress http://dx.doi.org/10.1094/PHP-12-16-0069BR.
16. Gosse, H. N., K. S. Lawrence, and Sang-Wook Park. 2017. Underground mystery: the role of chemotactic attractants in plant root and phytonematode interactins. Scientia Ricerca 1(2): 83-87.
17. Grabau, Z.J., Z.T.Z. Maung, C. Noyes, D. Baas, B.P. Werling, D.C. Brainard, and H. Melakeberhan. Effects of cover crops on Pratylenchus penetrans and the nematode community in carrot production. Journal of Nematology. Journal of Nematology 49, 114-123.
18. Groover, W., K.S. Lawrence, N. Xiang, S. Till, D. Dodge, D. Dyer, and M. Hall. 2017. Cotton variety selection with and without Velum Total for root-knot nematode management in central Alabama, 2016. Report No. 11:N014. DOI: 10.1094/PDMR11. The American Phytopathological Society, St. Paul, MN. http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N014.pdf
19. Groover, W., K. S. Lawrence, N. Xiang, S. Till, D. Dodge, D. Dyer, and M. Hall. 2017. Cotton variety selection with and without Velum Total for reniform management in north Alabama, 2016. Report No. 11:N015. DOI: 10.1094/PDMR11. The American Phytopathological Society, St. Paul, MN. http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N015.pdf
20. Groover, W., K. S. Lawrence, N. Xiang, S. Till, D. Dodge, D. Dyer, and M. Hall. 2017.Cotton seed treatment combinations for Rotylenchulus reniformis control and maximization of yield in north Alabama, 2016. Report No. 11:N016. DOI: 10.1094/PDMR11. The American Phytopathological Society, St. Paul, MN. http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N016.pdf
21. Groover, W. K. S. Lawrence, N. Xiang, S. Till, D. Dodge, D. Dyer, and M. Hall. 2017. Nematicide combinations for Rotylenchulus reniformis management in north Alabama, 2016. Report No. 11:N009. DOI: 10.1094/PDMR11. The American Phytopathological Society, St. Paul, MN. http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N009.pdf
22. Hall, M., K. Lawrence, W. Groover, D. Shannon, and T. Gonzalez. 2017. First Report of the Root-Knot Nematode (Meloidogyne incognita) on Curcuma longa in the United States. Plant Disease 101 (10):1826. https://doi.org/10.1094/PDIS-03-17-0409-PDN.
23. Hall, M., K. S. Lawrence, D. Dodge, D. Dyer, W. Groover, S. Till, and N. Xiang. 2017. Varietal and nematicidal application responses in central Alabama soils, 2016. Report No. 11:N024. DOI: 10.1094/PDMR11. The American Phytopathological Society, St. Paul, MN. http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N024.pdf
24. Hall, M., K. S. Lawrence, D. Dodge, D. Dyer, W. Groover, S. Till, and N. Xiang. 2017. Varietal and nematicidal application responses in north Alabama soils, 2016. Report No. 11:N2025. DOI: 10.1094/PDMR11. The American Phytopathological Society, St. Paul, MN. http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N025.pdf
25. Hall, M., K. S. Lawrence, D. Dodge, D. Dyer, W. Groover, S. Till, and N. Xiang. 2017. Velum Total and Vydate-L drip irrigation applications for southern root-knot nematode management in south Alabama, 2016. Report No. 11:N007. DOI:10.1094/PDMR11. The American Phytopathological Society, St. Paul, MN. http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N007.pdf
26. Hall, M., K. S. Lawrence, D. Dodge, D. Dyer, W. Groover, S. Till, and N. Xiang. 2017. Velum Total and Vydate-L drip irrigation applications for southern root-knot nematode management in south Alabama, 2016. Report No. 11:N008. DOI: 10.1094/PDMR11. The American Phytopathological Society, St. Paul, MN. http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N008.pdf
27. Ingham, R.E. 2017. Nematode management in the face of short supply of Telone and Vydate. Potato Progress. 17(7):1-5.
28. Kim, Ki-Seung, Dan Qiu, Tri D. Vuong, Robert T. Robbins, J. Grover Shannon, Zenglu Li, and Henry T. Nguyen. 2016. Advancements in breeding, genetics, and genomics for resistance to three nematode species in soybean. Theoretical and Applied Genetics 2295-2311.
29. Khanal, C., R.T. Robbins, Faske, A.L. Szalanski, E.C. McGawley, and C. Oversteet. 2016. Identification and haplotype designation of Melogogyne spp. of Arkansas using molecular diagnostics. 2016. Nematropica 46:261-270.
30. Klink VP, McNeece BT, Pant SR, Sharma K, Nirula PM, Lawrence GW. 2017. Components of the SNARE-containing regulon are co-regulated in root cells undergoing defense. Plant Signalling and Behavior Feb; 12(2):e1274481.
31. Land, C. J., K. S. Lawrence, C. H. Burmester, B. Meyer. 2017. Cultivar, irrigation, and soil contribution to the enhancement of Verticillium wilt disease in cotton. Drop Protection 96:1-6.
32. Lawrence, K. S., N. Xiang, W. Groover, S. Till, D. Dodge, D. Dyer, and M. Hall. 2017. Evaluation of commercial cotton cultivars for resistance to Fusarium wilt and Root-knot nematode, 2016. Report No. 11:N006. DOI: 10.1094/PDMR11. The American Phytopathological Society, St. Paul, MN. http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N006.pdf
33. Lee, M.W., A. Huffaker, D. Crippen, R.T. Robbins, and F. Goggin. 2017. Plant Elicitor Peptides Promote Plant Defenses against Nematodes in Soybean. Molecular Plant Pathology. Date: 27-June-2017, pp. 1 – 12, DOI : 10.1111/mpp.12570.
34. McNeece BT, Pant SR, Sharma K, Nirula PM, Lawrence GW, Klink 2017. A Glycine max homolog of NON-RACE SPECIFIC DISEASE RESISTANCE 1 (NDR1) alters defense gene expression while functioning during a resistance response to different root pathogens in different genetic backgrounds. Plant Physiology and Biochemistry 114:60-71.
35. Moye, Hugh. H. Jr., N. Xiang, K. Lawrence, and E. van Santen. 2017. First Report of Macrophomina phaseolina on Birdsfoot Trefoil (Lotus corniculatus) in Alabama. Plant Disease 101 (5): 842. https://doi.org/10.1094/PDIS-12-16-1750-PDN.
36. Olson, M., Harris, T., Higgins, R., Mullin, P., Powers, K., Olson, S. and Powers, T.O., 2017. Species Delimitation and Description of Mesocriconema nebraskense sp. (Nematoda: Criconematidae), a morphologically cryptic, parthenogenetic species from North American grasslands. Journal of Nematology, 49(1) 42-68.
37. Powers, T. O., Harris, T., Higgins, R., Mullin, P., and Powers, K. 2017. An 18S rDNA perspective on the classification of Criconematoidea. Journal of Nematology 49(3):236–244. 2017.
38. Till, S. R., K.S. Lawrence, N. Z. Xiang, W. L. Groover, D. J. Dodge, D. R. Dyer, and M. R. Hall. 2017. Yield loss of five corn hybrids due to the root-knot nematode and nematicide evaluation in Alabama, 2016. Report No. 11:N021. DOI: 10.1094/PDMR11. The American Phytopathological Society, St. Paul, MN. https://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N021.pdf
39. Till, S. R., K. S. Lawrence, N. Z. Xiang, W. L. Groover, D. J. Dodge, D. R. Dyer, and M. R. Hall. 2017. Corn hybrid and nematicide evaluation in root-knot nematode infested soil in Alabama, 2016. Report No. 11:NO23. DOI: 10.1094/PDMR11. The American Phytopathological Society, St. Paul, MN. http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N023.pdf
40. Till, S. R., K. S. Lawrence, N.Z. Xiang, W.L. Groover, D.J. Dodge, D.R. Dyer, and M.R. Hall. 2017. Cotton variety evaluation with and without Velum Total for root knot management in south Alabama, 2016. Report No. 11:N022. DOI: 10.1094/PDMR11. The American Phytopathological Society, St. Paul, MN.  http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N022.pdf
41. Xiang, Ni, K.S. Lawrence, J.W. Kloepper, P.A. Donald, and J.A. McInroy. 2017. Biological control of Heterodera glycines by spore-forming plant growth-promoting rhizobacteria (PGPR) on soybean. PLOS ONE 12(7): e0181201. https://doi.org/10.1371/journal.pone.0181201.
42. Xiang, Ni, K.S. Lawrence, J.W. Kloepper, P.A. Donald, J.A. McInroy, and G.W. Lawrence. 2017. Biological control of Meloidogyne incognita by spore-forming plant growth-promoting rhizobacteria on cotton. Plant Disease 101(5): 774-784. http://apsjournals.apsnet.org/doi/pdf/10.1094/PDIS-09-16-1369-RE
43. Xiang, N., K. S. Lawrence, W. Groover, D. Dodge, D. Dyer, and S. Till. 2017. Evaluation of Velum Total on cotton for reniform nematode management in North Alabama, 2016. Report No. 11:N010. DOI: 10.1094/PDMR11. The American Phytopathological Society, St. Paul, MN. http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N010.pdf
44. Xiang, N., K.S. Lawrence, W. Groover, D. Dodge, D. Dyer, and S. Till. 2017.Evaluation of Velum Total on cotton for root-knot management in central Alabama, 2016. Report No. 11:N011. DOI: 10.1094/PDMR11. The American Phytopathological Society, St. Paul, MN.http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2017/N011.pdf

Published Abstract:

1. Aljaafri, W.A.R., G.W. Lawrence, S. Lu, V.P. Klink, D.H. Long and K.S. Lawrence 2017. Ability of SAR-Saponin and A bacterial metabolite to reduce the soybean cyst nematode (Heterodera glycines) and the incidence of sudden death syndrome (Fusarium virguliforme). Phytopathology (in press).
2. Aljaafri, W.A.R., G.W. Lawrence, V.P. Klink, S. Lu, D.H. Long and K.S. Lawrence 2017. Biological seed treatments for Soybean Cyst Nematode (Heterodera glycines) management. Journal of Nematology (in press).
3. Bisho R.L., B. T. McNeece, S. R. Pant, K. Sharma, P. Niraula, K.S. Lawrence, G. W. Lawrence, V.P. Klink. 2017. The identification of genes having defense roles to nematodes through a functional development genomic screen. Journal of Nematology (in press).
4. Bisho R.L., B. T. McNeece, S. R. Pant, K. Sharma, P. Niraula, K.S. Lawrence, G. W. Lawrence, V.P. Klink. 2017. A functional developmental genomics screen is identifying genes functioning within cells that function in plant to a root pathogen. Phytopathology (in press).
5. Fatdal, L., B. Sipes, and M. Melzer. 2017. Bioforensic studies in Rotylenchulus reniformis – Sources and origin. Journal of Nematology 48: in press.
6. LaPorte, Patricia, 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 western highlands of Guatemala. Journal of Nematology 48: in press.
7. Marquez, J., K.-H.Wang, B.S. Sipes, and Z. Cheng. 2017. Improving soil conditions for entomopathogenic nematodes with no-till cover cropping. Journal of Nematology 48: in press.
8. Noyes, D.C., Z. Hayden, D. Baas, H. Melakeberhan, B. Werling and D.C. Brainard.  2017.  Cover crop effects on nitrogen and weeds in MI processing carrots.  38^th International Carrot Conference, CP-102, Bakersfield, CA, March (Oral). http://ucanr.edu/sites/test02082001/view_oral_presentation_abstracts/production/
9. Thomas, S.H., J. Beacham, and T.O. Powers. 2017. Suppression of Criconematid-induced injury to golf course greens in New Mexico.  Journal of Nematology 49: (in press).

Proceedings:

1. Faske, T., Lonoke, T. W. Allen, Mississippi State University, G. W. Lawrence, Kathy S. Lawrence, H. L. Mehl, R. Norton, Charles Overstreet, and T. Wheeler. 2017. Beltwide Nematode Research and Education Committee Report on Cotton Cultivars and Nematicides Responses in Nematode Soils, 2016. Proceedings of the 2017 Beltwide Cotton Conference Vol. 1: 270-273.  National Cotton Council of America, Memphis, TN. http://cotton.org/beltwide/proceedings/2010-2017/index.htm
2. Groover, W., Lawrence, N. Xiang, S. R. Till, D. Dodge, D. R. Dyer and M. Hall. 2017. Yield Loss of Cotton Cultivars Due to the Reniform Nematode and the Added Benefit of Velum Total. Proceedings of the 2017 Beltwide Cotton Conference Vol. 1: 216-219. National Cotton Council of America, Memphis, TN. http://cotton.org/beltwide/proceedings/2010-2017/index.htm
3. Hall, M., K. S. Lawrence, D. Dodge, D. R. Dyer, W. Groover, S. R. Till and N. Xiang. 2017. Varietal and Nematicidal Responses of Cotton in Nematode-Infested Soils. Proceedings of the 2017 Beltwide Cotton Conference Vol. 1: 211-215. National Cotton Council of America, Memphis, TN. http://cotton.org/beltwide/proceedings/2010-2017/index.htm
4. Ingham, R.E. 2017. Nematode management in the face of short supply of Telone and Vydate. 2017 Proceedings of the Washington - Oregon Potato Conference. Pp. 33-38.
5. Lawrence, K., A. Hagan, R. Norton, T. R. Faske, R. Hutmacker, J. Muller, D. L. Wright, I. Small, R. C. Kemerait, C. Overstreet, P. Price, G. Lawrence, T. Allen, S. Atwell, A. Jones, S. Thomas, N. Goldberg, R. Boman, J. Goodson, H. Kelly, J. Woodward and H. Mehl. 2017. Cotton Disease Loss Estimate Committee Reort, 2016. Proceedings of the 2017 Beltwide Cotton Conference Vol. 1: 150-151. National Cotton Council of America, Memphis, TN. http://cotton.org/beltwide/proceedings/2010-2017/index.htm
6. Robbins, R. T., P. Arelli, P. Chen, G. Shannon, S. Kantartzi, Z. Li, T. Faske, J. Vellie, E. Gbur, D. Dombek, and D. Crippe 2017. Reniform Nematode Reproduction on Soybean Cultivars and Breeding Lines in 2016. Proceedings Beltwide Cotton Conferences, Dallas, TX, January 4-6, 2017, pp 184-197.
7. Rothrock, C., S. Winters, T. W. Allen, J. D. Barham, W. Barnett, M. B. Bayles, P. D. Colyer, H. M. Kelly, R. Kemerait, G. W. Lawrence, K. Lawrence, H. L. Mehl, P. Price and J. Woodward. 2017. Report of the Cottonseed Treatment Committee for 2016. Proceedings of the 2017 Beltwide Cotton Conference Vol. 1: 153-160. National Cotton Council of America, Memphis, TN. http://cotton.org/beltwide/proceedings/2010-2017/index.htm
8. Till, S., K. S. Lawrence, D. Schrimsher and J. R. Jones. 2017. Yield Loss of Ten Cotton Cultivars Due to the Root-Knot Nematode and the Added Benefit of Velum Total. Proceedings of the 2017 Beltwide Cotton Conference Vol. 1: 205-207. National Cotton Council of America, Memphis, TN. http://cotton.org/beltwide/proceedings/2010-2017/index.htm
9. Xiang, N., M. S. Foshee, K. Lawrence, J. W. Kloepper and J. A. McInroy. 2017. Field Studies of Plant Growth-Promoting Rhizobacteria for Biological Control of Rotylenchulus Reniformis on Soybean. Proceedings of the 2017 Beltwide Cotton Conference Vol. 1: 201-204. National Cotton Council of America, Memphis, TN. http://cotton.org/beltwide/proceedings/2010-2017/index.htm

Book chapters:

• Thomas, S.H. and C. Nischwitz. Chapter 19:  Plant-parasitic nematodes in New Mexico and Arizona.  In Subbotin and J. Chitambar eds. Plant parasitic nematodes in sustainable agriculture of North America. Springer. (in review)