Brief Summary of Minutes of Annual Meeting

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

Alabama (Lawrence): Germplasm lines from the BARBREN and M713 groups derive this resistance to reniform nematode from a common source: wild accession GB-713 of G. barbadense. This commonality in background is reflected in the excellent results of all three parts of this study. All lines of these two groups yielded well under nematode free conditions, with BAR 41 matching those of conventional cultivar FM966. Yield reductions due to reniform nematode exposure were less than 10% for BAR 41 and all five M713 lines. The three MT2468 lines also reduced nematode reproduction, but suffered significant yield reductions of 50 to 70%, about equal to the yield losses sustained by the two susceptible controls. The high level of reniform susceptibility found in a limited number of LONREN individuals might indicate seed contamination due to outcrossing. The rapid assessment experiment on microplots yielded results which closely mimicked those obtained from the more elaborate field and greenhouse trials.

Arkansas (Robbins): In a greenhouse test for hosts of an Arkansas population of Meloidogyne partityla I tested Pecan (Very good Host); Eastern Black Walnut (Juglans nigra) host, Shagbark Hickory (Host); Southern Red Oak (Host); Burr Oak (?) and Pin Oak (?). More host test are started for several other tree species.  Efforts to identify Meloidogyne species of Arkansas are ongoing. No new species since the 2014 report.  I worked with soybean researchers from Missouri and Georgia to identify 27 soybean Plant introductions reported to have Soybean Cyst Nematode resistance for reniform nematode reproduction (resistance). Of the 27 PI’s six were resistant to reniform.  I have been testing reniform resistant lines of cotton with a seed company with the goal of finding lines with both reniform and root-knot resistance present.

California – Riverside (Roberts): Carrots are highly susceptible to several species of root-knot nematodes, which cause forking and galling distortion of the marketable taproot. A panel of eleven resistant carrot lines representing the known range of resistance sources to the common Melodiogyne spp. was screened in greenhouse pot tests with 45 Meloidogyne species isolates, including 29 of M. incognita, 11 of M. hapla, and others of M. javanica and M. arenaria. Overall resistance levels of some lines with known M. incognita resistance genes was effective against all isolates. The best sources of resistance were Brasilia (gene Mj-1 combined with additional M. incognita genes; and combinations of Brasilia and Homs resistance sources). The most virulent isolates causing slightly elevated root galling were still effectively controlled by the resistance. Some lines known to be virulent on the tomato resistance gene Mi-1.2 were not virulent on any of the resistant carrot lines in the panel. The most resistant taproots from these tests are being grown for selfing or crossing at the USDA, Madison WI carrot breeding program (P. Simon) to advance the development of RKN resistant carrot varieties for growers. 

Hawaii (Sipes): Breadfruit (Artocarpus altilis) is rapidly becoming a popular landscaping and food crop in Hawaii. Plant-parastic nematodes associated with breadfruit include Pratylenchus, Helicotylenchus, and Meliodogyne. On the islands of Kauai and Maui in Hawaii, Helicotylenchus spp. was dominant in all of the samples collected. Rotylenchulus and Paratylenchus were found in low populatons but were present in all soil samples. Other plant-parasitic nematode genera in the breadfruit-associated soils in Hawaii included Scutellonema, Pratylenchus, Mesocriconema, and Meloidogyne. A heteroderid nematode was also found in samples from Kauai and Maui. The population density and genera of plant-parasitic nematodes found in Hawaiian breadfruit soils could indicate damage to the crop and aid in developing a specific management approach for local growers and farmers of breadfruit. In addition to expanding the locations, collection and extraction from breadfruit roots would help elucidate which nematodes infect and parasitize breadfruit in Hawaii.

Michigan (Melakeberhan): Understanding nematode adaptation in mixed cropping systems and developing suitable nematode and crop yield management strategies is highly complex. In part, the difficulties arise from the agronomic practices (e.g. tillage, crop rotation, cover crop use and agricultural inputs) varying impacts on soil health, defined as the biological, physiochemical, nutritional, structural and water holding integrity of a given soil. While soil health directly or indirectly affects biological interactions, how agronomic practices exactly influence soil biology, which drives the soil food web and nutrient transformations, is less known. Comparative analyses of different cropping systems and land use practices suggest that critical factors that affect beneficial nematodes, indicator of soil health, and presence of harmful nematodes and their adaptation therein may be overlooked. First, on-going is a long-term study to determine how soybean cyst nematode (SCN, Heterodera glycines) adapts when introduced into a new location under till and no-till, and either corn (Zea mays, C), SCN race 3 resistant soybean (R, Glycine max), or susceptible soybean (S) monocrop, or RCRC and SCSC rotations. While SCN population density was lower in no-till than in tilled treatments, and highest in S and lowest in C or RC rotations, it was detected at less than one cyst per 100 cc of soil. This suggests a prolonged phase of decline from the introduced levels. Interaction effects of tillage, rotation and/or time on SCN suggest that outcomes vary by agronomic practice and time, providing agro-biologically based understanding of SCN establishment in a new location. Second, we examined how sugar beet varieties (EL53, EL57, EL59, EL61 and EL64 from the USDA laboratory at MSU) along with soybean and corn (standard rotation crops) affect sugar beet cyst nematode (SBCN) and other herbivore nematodes and soil health in different soil types in 2012 and 2013. Cyst and other herbivore nematode population dynamics, and soil food web data support the hypothesis that there are distinct interactions among the crops, nematodes and soil conditions. Third, how sugar beet (SBCN-tolerant, B-18RR4N and –susceptible, B-10RR34), cover and trap (oilseed radish: Defender and Tillage; mustard: Pacific Gold and Ida Gold)) crops, and soybean (SCN-resistant 92Y80 and SCN-susceptible 92M91) and corn (P9910R) affect soil health, nematode community and sugar beet production in sandy clay loam and loam soils was studied in 2013 and 2014. While the sandy clay loam soil was more stressed than the loam soil, principal component analysis showed distinct correlation patterns among nematode community indices and physiochemical properties in the soil types. Fourth, whether it was undisturbed (pristine forest or natural vegetation) or disturbed (agricultural or grazing) landscapes in Ferralsol, Lithosol and Nitosol soil groups, the herbivore nematodes Amplimerlinius, Heterodera and Trophurus in Ghana, Paratrophurus in Kenya, and Trichodorus and Longidorus in all three countries were present in Ferralsols only. Furthermore, multi-factor correlation analyses of nematode abundance and frequency, soil texture and physiochemical properties showed distinct separation of the soil groups and by country, and Ferralsols further from Lithosols and Nitosols. Although all biologically degraded, the results indicate that these soil groups have different biological properties and may not respond the same way to a given treatment. Collectively, the studies point to understanding the soil environment might be a key factor in determining nematode adaptation. Thus, providing basis for further investigations that might shed light on specificity of interactions at micro- and macro-environment levels. On-going are studies to characterize distribution and parasitic variability of the northern root-knot and cyst nematodes in the diverse Michigan cropping systems.

Mississippi (Lawrence & Klink): Genes functioning in membrane fusion were originally identified genetically in the baker’s yeast, Saccharomyces cerevisiae, and are found in all eukaryotes. Components of the membrane fusion unit function in the plant genetic model Arabidopsis thaliana during its defense to shoot pathogens. Regarding defense, little is understood about a root function. Experiments in Glycine max (soybean) have provided an opportunity to perform such studies, revealing that syntaxin 31 and alpha soluble NSF attachment protein (-SNAP) are expressed under natural conditions in root cells undergoing defense to parasitism by the nematode Heterodera glycines. Other genes functioning in membrane dynamics are also expressed, but have no obvious role in root biology or resistance. Presented here, G. max homologs of membrane fusion genes are shown to function in the resistance of G. max to H. glycines. In contrast, other genes functioning in various aspects of vesicle transport do not appear to function in resistance. These experiments point to the specificity of the transgenic approach used in the analysis and the process of resistance itself. Experiments show that the membrane fusion apparatus functions with a number of other genes during the process of resistance.

Nebraska (Powers) : We have continued to work on DNA barcoding for nematode identification and the construction of a reference database for DNA barcodes of plant parasitic nematodes. This past year we have focused on Pratylenchus species. We have been testing newly designed primer sets for COI which amplify 1000bp of the mitochondrial gene. Notable results include the observation that many agricultural fields in Great Plains and the Midwest contain a mixture of discrete haplotypes regardless of host. This means that many fields may have species mixtures that may favor different hosts in a crop rotation or may have specific weed hosts. We have recovered five primary haplotype groups in the region. One group appears to correspond to Pratylenchus penetrans and a second corresponds to P. thornei. A third group corresponds to what might be considered P. neglectus, P. scribneri, or P. hexincisus. The morphological characters that discriminate these there species do not appear to correspond to COI haplotype grouping. Specimens from each of the five haplotype groups have been associated with corn fields. We will continue to collect and analyze specimens from a wider geographic range.

New Mexico (Thomas & Hanson): In collaboration with Dr. S.F. Hanson’s lab, we investigating the feasibility of using deep sequencing methodologies to detect and identify Ditylenchus and Meloidogyne species in a manner suitable for use in examining high numbers of soil samples in a cost-effectively.  A standardized protocol was developed which reproducibly recovers high quality DNA from bulk nematode populations isolated from soil samples.  The procedure is a hybrid that begins with the high efficiency lysis of bulk nematode samples using the lysis procedure we previously developed for single nematodes.  This is followed by an affinity column purification step adapted from a commercial soil DNA purification kit (Power soil, Mo Bio Inc) to remove PCR inhibitors like humic acid from organic debris that is present in DNA prepared from bulk nematode samples.  We are currently running this procedure in a microfuge tube format that can process 24 samples in parallel in about 2 hours.  A single trained technician could feasibly extract DNA from 48-72 samples per day using this procedure.  Multiple tests showed that this procedure reliably produces PCR quality DNA whereas the lysis procedure on its own failed ~1/3 of the time.   We also designed primer sets and PCR profiles that allow amplification of PCR products that span an 1,800 bp region bridging 18S, ITS-1, 5.8S, ITS-2, and a portion of the 28S rRNA genes.  This span enables species level identification for Ditylenchus and meiotically-parthenogenetic Meloidogyne species using a single contiguous amplicon in a mixed sample without having to assemble sequences from different amplicons in-silico after sequencing.  These primers enabled positive identification of Meloidogyne chitwoodi and D. dipsaci from multiple samples submitted to the NMSU Nematode Containment Facility by the NM Department of Agriculture.

Oregon (Ingham): Biological characterization of Globodera ellingtonae.  On April 28, 2008, a field at the Oregon State University Powell Butte Farm that was planted to potato in 2007 was sampled and found to contain cysts of Globodera which were morphologically and molecularly distinct from golden potato cyst (G. rostochiensis), pale potato cyst (G. pallida), and tobacco cyst (G. tobaccum) nematodes.  Subsequently, in August and September of 2008 cysts matching the characteristics of those found at Powell Butte were recovered from two grower potato fields in Idaho.  These nematodes were later (2012) described as a new species, G. ellingtonae.  Very little is known about the biological properties of this species and its potential pathogenicity to potato or other crop plants.  Lab, greenhouse, and field studies have begun to help characterize the biology of G. ellingtonae.

To evaluate the pathogenic effects of G. ellingtonae on potato, six field trials over a four-year period were conducted.  In three trials (2012, 2013, 2014), single hills of potato ‘Russet Burbank’ were planted into soil infested with different initial densities (Pi) of G. ellingtonae (0, 5, 10, 20, 40, or 80 eggs/g soil) at the Central Oregon Agriculture Research Center farm at Powell Butte, OR.  In 2013, the trial was repeated with the red potato variety, ‘Désireé’.  In another trial (2014), five additional potato varieties varying in maturity lengths were either inoculated (80 eggs/g soil) or not with G. ellingtonae.  All trials were planted in a randomized block design with 7 or 8 replications on a 76 cm in-row spacing between plants.  At harvest, tops were removed, dried and weighed (2013 and 2014), and tubers were dug by hand and weighed.  Soil samples were taken from beneath each plant; cysts were extracted and crushed to determine the eggs per g soil (Pf).  Pf densites for Pi densities of 5, 10, 20, 40, and 80 eggs/g soil averaged 104, 121, 177, 234, and 229 eggs/g soil, respectively, for the four trials with variable Pi.  This suggests that some limit in nematode reproduction may have been reached between 40 and 80 eggs/g soil.  Only one of the trials (2013) conducted with increasing levels of Pi, resulted in a significant negative correlation between Pi and yield of ‘Russet Burbank’.  Combining data from the three years of ‘Russet Burbank’ trials in a multiple linear regression model indicated a significant effect of Pi on tuber yield.  Based on the linear regression model of tuber yield on log(Pi) with a single slope for the three Russet Burbank trials, 11.3 to 17.0% yield loss is predicted at a Pi of 40 eggs/g soil and 13.5 to 20.2% yield loss is predicted at a Pi of 80 eggs/g soil when tuber yields at Pi of 0 eggs/g soil are 1,829 to 2,744 g/plant.  None of the potato varieties (‘Russet Norkotah’, ‘Yukon Gold’, ‘Ranger Russet’, ‘Alturas’, ‘Umatilla Russet’) inoculated with 80 G. ellingtonae eggs/g soil had significantly reduced top weights or tuber yields compared to non-inoculated plants.  In 2015, one of these varieties (‘Ranger Russet’) was planted into soil infested with a range of very high initial densities (Pi = 0, 40, 80, 160, and 320 eggs/g soil) to see if an impact on yield could be determined at these densities.  Only top and tuber weights from the 320 eggs/g soil infestation level were significantly less than for plants grown in uninfested soil.  Care should be taken in extrapolating the results from this single field site to probable effects of G. ellingtonae on potato in other environments.

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

Alabama (Lawrence) Fusarium oxysporum  f. sp. vasinfectum (W. C. Snyder & H. N. Hansen) causes economic losses of Upland cotton (Gossypium hirsutum) yields throughout the cotton belt of the United States. An association with the Southern root-knot nematode (Meloidogyne incognita) was recognized early on in the discovery of the disease, forming a disease complex. Trials to screen commercially available cultivars for resistance or tolerance to the Fusarium wilt disease complex have indicated that the root-knot nematode is the disease pathogen driving the disease complex as measured by yield reduction.  Ranking the cultivars by yield indicated the highest yielding cultivars were Stoneville 4747 GLB2 followed by Phytogen 427 WRF, Phytogen 499 WRF, and Stoneville 4946 GLB2.  Phytogen 427 WRF, Stoneville 4946 GLB2 and Phytogen 499 WRF supported lower root-knot populations and little FOV disease incidence.  Stoneville 4747 GLB2 supported very low wilt incidence, but root-knot egg reproduction factors were not significant.  Deltapine 1454NR B2RF supported lower numbers of root-knot nematode eggs per gram of root fresh weight than the susceptible check Rowden and other commercial cultivars tested in the trial.  This variety performed the best when limiting root-knot nematode reproduction, but could be considered moderately susceptible to Fusarium wilt.  Race 1 was the predominant race found in Alabama, with 70% of isolates identifying as this race. 14% of isolates were LA 108, 8% were race 8, 7% were LA 127/140, and 0.008% were identified as race LA 110.

New Mexico (Thomas): The study established in late 2013 and repeated in 2014-2015 to determine if the previous crop species affects subsequent M. incognita reproduction on yellow and purple nutsedges was completed.  Analysis of data is in progress.  These studies are necessary to accurately predict how different cropping scenarios will impact root-knot nematode carryover to future crops from perennial weeds.  In both studies nutsedges were inoculated with eggs recovered from cotton, chile, or corn (the major summer annual crops in southern NM).  Inoculum from tomato was also included to allow extrapolation to results from previous studies.  The experiments are harvested upon accumulation of 750 heat units (DD24 = one life cycle for the nematode), and eggs extracted from roots.  Results will be used to calculate the crop-specific M. incognita carryover potentials for both nutsedge species for use to develop IPM management recommendations for the nutsedge/nematode pest complex. The percentage of yellow or purple nutsedge tubers that harbored M. incognita was not affected by crop, suggesting that tubers from both nutsedge species provide a consistent reservoir of nematodes to infect future crops.  In a separate series of experiments begun in Fall 2015, the Ditylenchus dipsaci population detected in a large-scale home garlic production system are being examined for potential to infect regional varieties of alfalfa and commercial bulb onions. 

Utah (Adams): Parasitism is a major ecological niche for a variety of nematodes. Multiple nematode lineages have specialized as pathogens, including deadly parasites of insects that are used in biological control. We have sequenced and analyzed the draft genomes and transcriptomes of the entomopathogenic nematode Steinernema carpocapsae and four congeners (S. scapterisci, S. monticolum, S. feltiae, and S. glaseri).  We used these genomes to establish phylogenetic relationships, explore gene conservation across species, and identify genes uniquely expanded in insect parasites. Protein domain analysis in Steinernema revealed a striking expansion of numerous putative parasitism genes, including certain protease and protease inhibitor families, as well as fatty acid- and retinol-binding proteins. Stage-specific gene expression of some of these expanded families further supports the notion that they are involved in insect parasitism by Steinernema. We show that sets of novel conserved non-coding regulatory motifs are associated with orthologous genes in Steinernema and Caenorhabditis.

To assess the impact of FTCs on cold-adapted soil biota, we evaluated freeze-thaw dynamics (i.e., 0°C crossings) and demographics of the dominant nematode, Scottnema lindsayae, (proportion of adults, population size) over 20 years in soils at two locations in Taylor Valley, Antarctica. Based on hourly soil temperature data, we demonstrate that FTCs are a frequent feature in Taylor Valley, but with high inter-annual and spatial variability. Valley topography and soil moisture were found to impact FTC frequency, suggesting that basins within Taylor Valley have different susceptibilities to environmental variability. Increased FTC frequency in 1999–2001 coincided with a shift in S. lindsayae populations, with fewer juveniles reaching maturity. In the years following decreased adult proportions, overall S. lindsayae numbers were reduced, implying a strong negative effect of FTCs on in situ recruitment. Our results suggest that increased FTC frequency in the Dry Valleys slows S. lindsayae development, reducing reproductive success and may take years to impact population size, which demonstrates the importance of long-term research to accurately predict the consequences of climate change on soil biota and biogeochemical cycling in the cold regions.

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

Arkansas (Robbins) Annually I test all new soybean entries submitted to the Arkansas Soybean Variety Testing Trials for reniform nematode reproduction. In 2015 this was 116 entries. A single plant of each variety was grown in each of 5 separate 4 inch diameter clay pots. As a germinated seedling was transplanted into each pot it was inoculated with 2,000 vermiform reniform nematodes. Two resistant varieties (Hartwig and Anand) were used as resistant checks while Braxton and Ellis was used as the susceptible checks. One pot in each rep was inoculated and left fallow as a check on reniform survival. The test was terminated after 12 weeks. Of the 116 entries there were seven that did not differ in reproduction than the resistant varieties Hartwig and Anand) and have probable rotation usefulness. Similar tests were also done for 219 varieties and breeding lines submitted by Southern Public Soybean Breeders from Arkansas (Chen), Southern Illinois (Kantartzi), Missouri (Shannon), and Georgia (Li). Of the 219 entries, 19 were as resistant as the resistant varieties Anand and Hartwig.  The specifics including statistical analysis (RTR) will be reported at the Beltwide Cotton Conferences in New Orleans in January 2016.

Hawaii (Sipes): Reniform nematode, Rotylenchulus reniformis, is a major pest of pineapple in Hawaii, reducing pineapple marketable yield by 26.8-50%. We determine if spirotetramat was active against reniform nematode in greenhouse and in vitro assays. Tomato plants were also treated 7-dpi and terminated at 14-dpt or 21-dpi to assess penetration. Reniform nematode eggs were also subjected to the spirotetramat in vitro to assess hatching. At 200 g a.i/ha, pineapple above ground biomass increased by 34.27% and root growth increased by 43.05% while reducing the root nematode population by 92.65% compared to untreated control. Nematode penetration at 50 or 100 g a.i/ha did not occur. Hatching was comparable in all treatments. Among all the treatment rates, 200 g a.i/ha significantly reduced the nematode population and enhanced the plant growth. No effect on hatch indicated that spirotetramat is only active through ingestion. In Odisha, India, as in many developing regions, the adoption rate of innovative farm technology is low as the farmers are generally risk averse. Traditional agricultural practices include multiple plowings for land preparation, mono-cropping, and fallowing the land after two cropping seasons. This traditional farming system is not sustainable, particularly on hilly slopes, where the current practices result in soil erosion and sub-optimal production. Conservation Agriculture Production Systems (CAPS) have been proven to work in other countries with similar environments. Finding early adopters to practice CAPS on their fields will help achieve higher adoption rates, as early adopters can influence other farmers. A survey for farmers in Rudhiapada and Badamahulidiha uncovered socio-economic determinants of early adopters. Forty six tribal farmers were surveyed to determine whether the farmers adopted a previously-introduced high yielding maize cultivar technology and to assess these farmers' profiles. Among these farmers, 50% had adopted the maize technology. By knowing the determinants of these early adopters, decision makers and extension can target farmers as leaders and early practitioners of desirable practices such as CAPS.

Idaho (Hafez): 2015 three new products for the management of mint nematodes were field tested in two irrigation systems, drip-line and furrow. Products were applied by injection for drip-line or foliar application for furrow irrigation. A single application of each chemical under each irrigation system was made. The field was allowed to grow under standard practice for the duration of the season. In September 2015 a 65 square foot area was harvested from each plot and weighed. 21 pounds of the sample were dried for oil extraction at the end of the season. Oil was extracted using a small University distillery and measured in milliliters. Data was compiled and means were separated using Duncan’s new multiple range test. Differences were only considered significant if P≤0.05. Data indicates that applications made in furrow irrigation systems may result in a higher hay yield as compared to the untreated control, however no significant difference in oil yield were found. Further study on field efficacy under different irrigation systems is planned for the 2016 season.

A continuous survey of mint fields throughout Idaho and Eastern Oregon has provided a list of common nematodes and their relative population densities. Yearly spreadsheets are constructed that indicate species, density, county and city of extraction. Thus far data has determined that lesion nematodes are the most common mint nematodes and pin nematodes have the highest density. This survey is projected to continue through 2017.

Greenhouse and microplot trials have started to determine the pathogenicity of pin nematode in mint. Trials will include determination of pin nematode thresholds and interactions with Verticillium wilt infection. Trials are in currently in their preliminary stages and are projected to see results in the near future.

Michigan (Melakeberhan): On-going are efforts to refine the fertilizer use efficiency (FUE) model, which separates nutrient deficiency and toxicity from nematode (pest) suppression and agro-ecological efficiency. These include integrating the FUE model with the soil food web model, which describes soil conditions and nutrient transformations in response to treatment.

Mississippi (Lawrence): Agricultural chemical companies are in the process of developing products designed for nematode control in row and vegetable crops. Efficacy studies have been conducted in 2015 with the products listed in Table 1 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.

New Mexico (Thomas):  A study begun in late 2013 to evaluate the efficacy of Avid^® (2% abamectin) for management of severe damage to bentgrass greens at the University of NM golf course resulting from high populations of Mesocriconema spp., Pratylenchus spp., and Longidorus breviannulatus was continued in 2015.  Annual application at maximum rates continues to provide effective suppression of     Mesocriconema spp and Longidorus breviannulatus, maintaining populations below the damage threshold and enabling a return to full use of the course.  Populations of Pratylenchus continue to increase and show little response to treatment.  However, damage symptoms on greens have not been apparent.  In another study management of M. incognita was attempted in chile pepper using the bionematicide Huma Gro^® Promax^TM, due to the lack of availability of oxamyl (the preferred treatment).  The product failed to provide suppression of soil populations measured at thinning (mid-June) or harvest (mid-September).  

Journal Articles:

Chen, P.,  C. P. Gray, T.L. Hart, M. Orazaly, J.C. Rupe, D.G. Dombek, R.D.

Bond, T. Kirkpatrick, R.T. Robbins, and L.O. Ashlock. 2014. Registration of ‘UA 5612’ soybean.  J. of Plant Reg. 8(2):145-149.

Chen, P., M. Orazaly, J.C. Rupe, D.G. Dombek, T. Kirkpatrick, R.T. Robbins, C. Wu, and P. Manjarrez. 2014. Registration of ‘UA 5213C’ soybean. J. of Plant Reg. 8(2): 150-154.

Dillman, A. R., M. Macchietto, C. F. Porter, A. Rogers, B. Williams, I. Antoshechkin, M.-M. Lee, Z. Goodwin, X. Lu, E. E. Lewis, H. Goodrich-Blair, S. P. Stock, B. J. Adams, P. W. Sternberg, and A. Mortazavi. 2015. Comparative genomics of Steinernema reveals deeply conserved gene regulatory networks. Genome Biology 16:1-21.

Huynh B.-L., W.C. Matthews, J.D. Ehlers, M. Lucas, J.P. Santos, A. Ndeve, T.J. Close and P.A. Roberts. 2015. A major QTL corresponding to the Rk locus for resistance to root-knot nematodes in cowpea (Vigna unguiculata L. Walp.). Theoretical and Applied Genetics: 1-9. DOI 10.1007/s00122-015-2611-0

Knox, M. A., D. H. Wall, R. A. Virginia, M. L. Vandegehuchte, I. S. Gil, and B. J. Adams. 2015. Impact of diurnal freeze–thaw cycles on the soil nematode Scottnema lindsayae in Taylor Valley, Antarctica. Polar Biology:1–10.

Ingham, R.E., D. Kroese, and I.A. Zasada. 2015. Effect of Storage Environment on Hatching of the Cyst Nematode Globodera ellingtonae. Journal of Nematology 47:45-51.

Lee, H. K., G. W. Lawrence, J. L. DuBien, and K. S. Lawrence. 2015. Seasonal variation and cotton-corn rotation in the spatial distribution of Rotylenchulus reniformis in Mississippi cotton soils. Nematropica 45:72-81.  http://journals.fcla.edu/nematropica/article/view/85053/81982

Li, Ruijuan, Aaron M. Rashotte, Narendra K. Singh, Kathy S. Lawrence, David B. Weaver, and Robert D. Locy. 2015. Transcriptome Analysis of Cotton (Gossypium hirsutum L.) Genotypes That Are Susceptible, Resistant, and Hypersensitive to Reniform Nematode (Rotylenchulus reniformis. PONE-D-15-10976R2

Melakeberhan, H., Wang, W., Kravchenko, A. and  Thelen, K. 2015. Effects of agronomic practices on the timeline of Heterodera glycines establishment in virgin land. Nematology 17:705-713.

Nair, M.G., Seenivasan, N., Liu, Y., Feick, R.M., Maung, Z.T.A. and Melakeberhan, H. 2015. Leaf constituents of Curcuma spp. suppress Meloidogyne hapla and increase bacterial-feeding nematodes. Nematology 17:353-361.

Pant SR, McNeece BT, Sharma K, Nirula PM, Jiang J, Harris JL, Lawrence GW, Klink V.P. 2015. A plant transformation system designed for high throughput genomics in Gossypium hirsutum to study root-organism interactions. Journal of Plant Interactions 10:11–20

Pant SR, Krishnavajhala A, Lawrence GW, Klink VP. 2015. A relationship exists between the cis-Golgi membrane fusion gene syntaxin 31, salicylic acid signal transduction and the GATA-like transcription factor, LESION SIMULATING DISEASE1 (LSD1) in plant defense. Plant Signaling & Behavior 10:1, e977737

Rudolph, R.E., C. Sams, R. Steiner, S.H. Thomas, S. Walker, and M.E. Uchanski. 2015.  Biofumigant performance of four Brassica crops in a green chile pepper (Capsicum annuum) rotation system in southern New Mexico.  HortScience 50:247-253.

Yongqing Jiao, Tri D. Vuong, Yang Liu, Zenglu Li, Jim Noe, Robert T. Robbins, Trupti Joshi, Dong Xu, J. Grover Shannon, and Henry T. Nguyen. 2015. Identification of quantitative trait loci underlying resistance to southern root-knot and reniform nematodes in soybean accession PI 567516C. Molecular Breeding (2015) 35:131

Zasada, I.A., R.E. Ingham, and W.S. Phillips. 2015. Biological insights into Globodera ellingtonae. In: Back. M., V. Block, I. Grove, S. Hockland and J. Pickup (eds). 4^th Symposium of Potato Cyst Nematode Management (including other nematode parasites of potatoes). Aspects of Applied Biology 130: 42-47.

Zhao, C., Y. Feng, R. Mathew, K. Lawrence, and S. Fu. 2015. Soil microbial community structure and activity in a 100-year-old fertilization and crop rotation experiment. Journal of Plant Ecology doi:10.1093/jpe/rtv007 http://gce.henu.edu.cn/images/Papers/zhao3.pdf

Published Abstract:

Beacham, J. S. Thomas, J. Schroeder,  L. Holland, E. Morris, N. Schmidt, L. Murray, F. Solano-Campos, S. Hanson, and J.D. Eisenback.  2015. Host status of a new Meloidogyne species found parasitizing yellow and purple nutsedges. Journal of Nematology 47: (in press)

Habteweld, A., Brainard, D., Ngouajio, M., Kravchenko, A., Grewal, S. P. and Melakeberhan, H. 2015. Integrating the concepts of fertilizer use efficiency and nematode-based soil food web models for broader use in soils health management. 54^th Annual Meeting of the Society of Nematologists Program Abstracts. 52.

Khanal, Churamani, R. T. Robbins, E. C. McGawley, and C. Overstreet 2015. Meloidogyne spp. reported from Arkansas: past and present. Program and Abstracts, 54^th Annual Meeting of the Society  of Nematologists. East Lansing, Michigan

Lawrence, K. S. and G. W. Lawrence. 2015. The fungicide fluopyram exhibits nematicide activity toward Rotylenchulus reniformis. Proceeding of the XVIII International Plant Protection Congress Belin, Germany, August 24-27, 2015. Vol. 1:241. http://domains.conventus.de/fileadmin/media/2015/ippc/IPPC2015_Abstractbook.pdf

Luangkhot, J. A., K.S. Lawrence, A.L. Smith. 2015. Evaluation of plant hormones and starter fertilizers on plant development in the presence of M. incognita or R. reniformis. 2015 Phytopathology 105:(In Press)

Maung, Z.T.A., Poindexter, S., Clark, G, Stewart, S, Hubbell, L. and Melakeberhan, H. 2015. Effects of rotation and cover crops on nematode communities and soil health in different sugar beet production soils. 54^th Annual Meeting of the Society of Nematologists Program Abstracts. 64.

Maung, Z.T.A., Yildiz, S, Kimenju, W. Kwoseh, C, Saka, V. and Melakeberhan, H. 2015. Soil health in three African soil groups revealed by nematode community analysis. 54^th Annual Meeting of the Society of Nematologists Program Abstracts. 63.

Sundararaj, P. P. and S.L. Hafez. 2014. Effect of chemical nematicides on the management of Columbian root knot nematode Meloidogyne chitwoodi on potato. Presented in the AZRA Silber Jubilee International Conference “Probing Biosciences for Food Security & Environmental Safety” on 16-18 February, 2014, held at CRRI, Cuttack, India.

Robbins, R. T., Ben Fallen, G. Shannon, P. Chen, S. K. Kantartzi, Travis R Faske, L. E. Jackson, E. E. Gbur, D. G. Dombek and J. T. Velie. 2015. Reniform Nematode Reproduction on Soybean Cultivars and Breeding Lines in 2014. Proceedings Beltwide Conferences 2015, San Antonio.

Saad L. Hafez and Christeena H. Sevy. Efficacy and optimum application timing of Movento for management of sugar beet cyst nematodes in sugar beet, 2014. 54^th Annual Meeting of the Society of Nematologist, Lansing, Michigan, July 19-24, 2015.  

Saad L. Hafez and P. Sandararaj. Effect of Movento alone or in combinations with Vydate and Vapam on Columbia root-knot nematode and potato yield, 2011. 54^th Annual Meeting of the Society of Nematologist, Lansing, Michigan, July 19-24, 2015.

Saad L. Hafez, C. Sevy and P. Sandararaj. Effect of Movento alone or in combinations with other nematicides on Meoidogyne chitwoodi and Heterodera schachtii on sugar beet. 54^th Annual Meeting of the Society of Nematologist, Lansing, Michigan, July 19-24, 2015.

Saad L. Hafez and C. Sevy. New chemistries and compounds for nematode management in potatoes. 54^th Annual Meeting of the Society of Nematologist, Lansing, Michigan, July 19-24, 2015. 

Xiang, N., and K.S. Lawrence. 2015. Biological potential of Bacillus spp. to reduce the populations of Heterodera glycines and promote plant growth in soybean. 2015 Southern Division - American Phytopathological Society. Phytopathology. 105(Suppl. 2):S2.12-13.http://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO-105-4-S2.1

Xiang, N., K.S. Lawrence, J.W. Kloepper, and J.A. McInroy. 2015. Plant growth promotion of PGPR on soybean and cotton with and without Heterodera glycines or Meloidogyne incognita. 2015. APS Annual Meeting. Phytopathology 105:(In press).

Xiang, N., K.S. Lawrence, J. W. Kloepper, and J. A. McInroy. 2015. Biological control and plant growth promotion of Bacillus spp. on Heterodera glycines in Soybean. 2015 10th International PGPR Workshop. In press. 

Proceedings:

Land, C. J., K. S. Lawrence, B. Meyer, C. H. Burmester. 2015. Applied Management Strategies for Verticillium Wilt and On-Farm Cotton Cultivar Variety Evaluations. 2014. Proceedings of the Beltwide Cotton Conference, (In Press). National Cotton Council of America, Memphis, TN. http://www.cotton.org/beltwide/proceedings/2005-2012/index.html

Land, C. J., K. S. Lawrence, P. Cobine, G. Lawrence. 2015. Tiger Striping Symptoms Caused by Rotylenchulus reniformis in Upland Cotton. 2014. Proceedings of the Beltwide Cotton Conference, (In Press). National Cotton Council of America, Memphis, TN. http://www.cotton.org/beltwide/proceedings/2005-2012/index.html

Land, Caroline, K. S. Lawrence, C. H. Burmester, and B. Meyer. 2015. Applied management options to enhance crop safety against Verticillium wilt. Proceedings of the 8th International IPM Symposium, Salt Lake City, UT, March 5-7, 2015: Vol. 1:74-75. http://ipmcenters.org/ipmsymposium15/Documents/IPM_2015_Proceedings-final.pdf

Lawrence, K., M. Olsen, T. Faske, R. Hutmacher, J. Muller, J. Mario, R. Kemerait, C. Overstreet, P. Price, G. Sciumbato, G. Lawrence, S. Atwell, S. Thomas, S. Koenning, R. Boman, H. Young, J. Woodward, and H. Mehl. 2015. Cotton disease loss estimate committee report, 2014. Proceedings of the 2014 Beltwide Cotton Conference Vol. 1: 188-190. National Cotton Council of America, Memphis, TN. http://www.cotton.org/beltwide/proceedings

Lawrence, K., P. Huang, G. Lawrence,T. Faske, C. Overstreet, T. Wheeler, H. Young, R. Kemerait, and H. Mehl. 2015. Beltwide Nematode Research and Edication Committee 2014 Nematode Research Report. Cotton varietal and nematicide responses in nematode soils. Cotton disease loss estimate committee report, 2014. Proceedings of the 2014 Beltwide Cotton Conference Vol. 1: 739-742. National Cotton Council of America, Memphis, TN. http://www.cotton.org/beltwide/proceedings

Lawrence, K. S. and G. W. Lawrence. 2015. A new fungicide, insecticide, nematicide combination for nematode management in cotton. Proceedings of the 8th International IPM Symposium, Salt Lake City, UT, March 5-7, 2015: Vol. 1:72-73. http://ipmcenters.org/ipmsymposium15/Documents/IPM_2015_Proceedings-final.pdf

Luangkhot, J. A., K.S. Lawrence, C. Land, K. Glass. 2015. Potential Nematicide Yield Benefit and Reniform Yield Reduction to Selected Cotton Cultivars. Proceedings of the 2015 Beltwide Cotton Conferences, San Antonio, TX, January 5-7, 2015: In Press. National Cotton Council of America, Memphis, TN. http://www.cotton.org/beltwide/proceedings

Robbins, R. T., B. Fallen, G. Shannon, P. Chen, S. K. Kantartza, T.R. Faske, L.E. Jackson, E.E. Gbur, D.G. Dombek, J.T. Velie, and P. Arelli. 2015. Reniform nematode reproduction on soybean cultivars and breeding lines in 2014.  Proceeding of the 2015 Beltwide Cotton Conferences, San Antonia, TX.  Jan 6-7. Pgs. 201-214.

Shankar R. Pant, Brant T. McNeece, Keshav Sharma, Prakash M. Nirula, Jian Jiang, Gary W. Lawrence & Vincent P. Klink (2015) THa development of a plant transformation system for high throughput genomics in Gossypium hirsutum to study root–organism interactions.Proceedings of the Beltwide Cotton Conferences. January 5-7, 2015 San Antonio, Texas  

Smith, A. L., K. S. Lawrence, K. Glass, and E. van Santen. 2015. Evaluation of Fusarium wilt resistance in cotton cultivars and identification of pathogenic races of Fusarium oxysporum f. sp. vasinfectum in Alabama. Proceedings of the 2015 Beltwide Cotton Conferences, San Antonio, TX, January 5-7, 2015: In Press. National Cotton Council of America, Memphis, TN. http://www.cotton.org/beltwide/proceedings 

Smith, Amber L., K. S. Lawrence, K. Glass, and D. Van Santen. 2015. Management of fusarium wilt in upland cotton of the southeastern United States. Proceedings of the 8th International IPM Symposium, Salt Lake City, UT, March 5-7, 2015: Vol. 1:75. http://ipmcenters.org/ipmsymposium15/Documents/IPM_2015_Proceedings-final.pdf

Zbylut, J., L. Murray, S.H. Thomas, J. Beacham, J. Schroeder, C. Fiore. 2015.  Modeling ratios with potential zero-inflation to assess soil nematode community structure.  Proceeding of the 25^th Annual Kansas State University Conference on Applied Statistics in Agriculture: 130-148.

Extension publications:

Cassida, K., Melakeberhan, H., Robertson, P. and Snapp, S. 2015. No matter how you slice it, healthy soil is important. Michigan State University, AgBioResearch Features. http://agbioresearch.msu.edu/news/no_matter_how_you_slice_it_healthy_soil_is_important?utm_source=MSU+AgBioResearch+E-Newsletter&utm_campaign=d2b52059b8-Futures_Spring_Summer_2015&utm_medium=email&utm_term=0_766437723c-d2b52059b8-230134969. Posted on July 26, 2105.

Lawrence, K. S., C. D. Monks, and D. Delaney. Eds. 2015 AU Crops: Cotton Research Report. March 2014. Alabama Agricultural Experiment Station Research Report Series No. 44. file:///F:/2011%20Passport/AU%20Crops%20report/AU%20Crops%20cotton%20%20report%202015/Cotton%20Bulletin%202015.pdf

Land, C.J., K. S. Lawrence, C. H. Burmester, and C. Norris. 2015. Bayer CropScience experimental Nematicides for Management of the Reniform Nematode in North Alabama, 2014. Report9:N014 DOI:11.1094/PDMR09. The American Phytopathological Society, St. Paul, MN.

Lawrence, K., C. Land, R. Sikkens, C. H. Burmester; C. Norris. Cotton nematicide combinations for reniform management in north Alabama, 2014. Report9:N002 DOI:11.1094/PDMR09. The American Phytopathological Society, St. Paul, MN.

Lawrence, K., C. Land, R. Sikkens. Cotton variety and nematicide combinations for root knot management in central Alabama, 2014. Report9:N003 DOI:11.1094/PDMR09. The American Phytopathological Society, St. Paul, MN.

Lawrence, K., C. Land, R. Sikkens, C. H. Burmester; C. Norris. Cotton variety and nematicide combinations for root-knot management in central Alabama, 2014. Report9:N004 DOI:11.1094/PDMR09. The American Phytopathological Society, St. Paul, MN.

Land, C.J., K. S. Lawrence, B. Miller. 2015. Experimental ReSet for management of the Root-knot on Cucumber, 2014. Report9: N012 DOI:11.1094/PDMR09. The American Phytopathological Society, St. Paul, MN.

Land, C.J., K. S. Lawrence, C. H. Burmester, and B. Meyer. 2015. Verticillium Wilt on-farm Cotton Cultivar Variety Evaluations, 2014. Report9: FC098 DOI:11.1094/PDMR09. The American Phytopathological Society, St. Paul, MN.

Land, C.J., K. S. Lawrence, C. H. Burmester, and C. Norris. 2015. Experimental Propulse and its efficacy on the Reniform Nematode in North Alabama, 2014. Report9: N011 DOI:11.1094/PDMR09. The American Phytopathological Society, St. Paul, MN.

Saad L. Hafez and Mahesh P. Pudasaini, 2015. Efficacy of Movento alone or in combinations with other compounds in drip irrigation system for the management of onion nematodes, 2013. Plant Disease management report, Vol. 9.

Saad L. Hafez and Mahesh P. Pudasaini, 2015. Effect of Movento alone of in combinations with Vydate or Vapam for control of Columbia root-knot nematode in Potato, 2012. Plant Disease management report, Vol 9.

Saad L. Hafez and Mahesh P. Pudasaini. 2015. Optimum timing of Movento application for control of Columbia root-knot nematode in Potato, 2012. Plant Disease management report, Vol 9.

Saad L. Hafez and P. Sundararaj. 2015. Effect of Vapam alone or with Adsorb on Columbia root-knot nematode and potato yield, 2011. Plant Disease management report, Vol 9.

Saad L. Hafez and P. Sundararaj. 2015. Efficacy of Telone II for the control of Columbia root-knot nematode on potato, 2010. Plant Disease management report, Vol 9.

Saad L. Hafez and P. Sundararaj. 2015. Effect of Movento alone or in combinations with Vydate and Vapm on Columbia root-knot nematode and potato yield, 2011. Plant Disease management report, Vol 9.

Saad L. Hafez and P. Sundararaj. 2015. Effect of different chemicals for the management of Columbia root-knot nematode on potato, 2011. Plant Disease management report, Vol 9.

Saad L. Hafez and P. Sundararaj. 2015. Effect of MCW on Columbia root-knot nematode and potato yield, 2011. Plant Disease management report, Vol 9.

Saad L. Hafez and P. Sundararaj. 2015. Effect of MCW-2 on Columbia root-knot nematode and potato yield, 2011. Plant Disease management report, Vol 9.

Saad L. Hafez and P. Sundararaj. 2015. Effect of MCW-2 formulations at different rates on potato and root lesion nematode under greenhouse conditions, 2011. Plant Disease management report, Vol 9.

Saad L. Hafez and P. Sundararaj. 2015.Effect of MCW-2 alone or in combination with Vydate on Tobacco rattle virus and potato yield, 2011. Plant Disease management report, Vol 9.

Saad L. Hafez and P. Sundararaj. 2015. Evaluation of new chemicals for the management of Columbia root-knot nematode on potato, 2010. Plant Disease management report, Vol 9.