Brief Summary of Minutes of Annual Meeting

Minutes of the NE-1040 Annual Meeting Oct. 3-4, 2013, Geneva New York. Participants: Administrative Advisor, Janine Sherrier, Associate Dean for Research, University of Delaware Chair, Jim LaMondia, Connecticut Agricultural Experiment Station. Technical Committee Members George Abawi, New York, Geneva, Cornell University Ernest Bernard, Tennessee, University of Tennessee George Bird, Michigan, Michigan State University Senyu Chen, Minnesota, University of Minnesota Don Dickson, Florida, University of Florida John Halbrendt, Pennsylvania, Pennsylvania State University Jim Kotcon, West Virginia, West Virginia University Jim LaMondia, Connecticut, Connecticut Agricultural Experiment Station Haddish Melakeberhan, Michigan, Michigan State University Nathaniel Mitkowski, Rhode Island, University of Rhode Island Deb Neher, Vermont, University of Vermont Larry Phelan, Ohio, Ohio State University Rob Wick, Massachusetts, University of Massachusetts Kyle Wickings, New York, Geneva, Cornell University The meeting convened at 8 AM, Oct. 3, 2013 at the Ramada Geneva Lakefront, with Jim LaMondia as Chair. Jim Kotcon volunteered to serve as Secretary. Opening announcements were made by Local Arrangements Chair, George Abawi. The Administrative Advisor, Dr. Janine Sherrier discussed allocation of Funds for travel publications. She described change at USDA in research programs, including an emphasis on more integration of projects, research and extension should be included in every project. Research proposals should use, for example, 4-H and Extension to increase outreach. The emphasis in the NE-1040 project on looking at soil health and sustainability is the right way to approach nematodes. Annual reports need an impact statement, identifying what things are transformational, and what is valuable and impactful in this program? It was suggested that we work with a Science writer to generate a document. A Request to Renew the NE-1040 project needs to be submitted in early 2014. State reports were presented from Connecticut by James LaMondia, Florida by Don Dickson, Michigan by George Bird and Haddish Melakeberhan, Minnesota by Senyu Chen, Massachusetts by Robb Wick, New York by George Abawi, Ohio by Larry Phelan, Pennsylvania by John Halbrendt, and Rhode Island by Nathaniel Mitkowski The meeting recessed at 5 PM, and reconvened at 8:30 AM on October 4, 2013. Additional State Reports were presented from Tennessee by Earnest Bernard, Vermont by Deb Neher, and West Virginia by James Kotcon. The Business Meeting commenced at 10 AM. George Bird has compiled a summary of Milestones in the extensive history of the project, including work from successive projects beginning with NE-34 and including NE-171, NE-1019, and NE 1040. Mid-Term Review. Jim LaMondia will send a reminder to Committee, asking for impact statements and other details needed by Janine Sherrier for a Mid-term Review. Since annual reports are limited to a couple pages, the Committee needs to boil it down to 2 pages. Proposed Milestones. 1) A workshop on soil health scheduled for 2014 will be postponed to 2015, in conjunction with SON. 2) Project needs 2-3 to put in a major research grant 3) Prepare an outreach publication. Sarah Delheimer is an impact writer in western region. Identify major impacts of project. Also, soil health publication would be logical outcome of workshop. George Bird introduced Jarrett Alli at MSU. He is focusing on chemical ecology, multi-trophic interactions and nematode responses to signaling to manipulate nematode behavior. He is currently a postdoc at Ithaca in ecology and Evolutionary biology program, working on molecular probes and primers to identify responses to signaling. He is also studying milkweed roots and how long-horn beetles fend off entomopathogenic nematodes. The Committee approved sending a plaque and letter of appreciation for Lou Magnarelli, past Administrative Advisor who passed away earlier this year. Don Dickson moved that the Committee express appreciation to George Abawi for hosting the meeting, and for outstanding local arrangements, and especially for the apples. The resolution was adopted by acclamation. The next meeting will be in West Virginia for 2014. The Committee accepted an invitation to meet in Jacksonville Florida in 2015. The meeting adjourned at 11:25AM Respectfully submitted by James Kotcon, Secretary.

Accomplishments: Objective 1: Develop effective and economically-viable cultural management tactics for plant-parasitic nematodes based on host resistance, nematode antagonistic rotation or cover crops, soil amendments and biological agents. Biological Control. - Votivo®, a biological control agent (Bacillus firmus) from Bayer, was evaluated for Heterodera glycines control in Michigan. The trial appears to have an excellent response with susceptible PI 88788 and PI 548402 varieties. Greenhouse trials with Pasteuria sp. were also conducted for control of H. schachtii. The results are currently proprietary information. Pasteuria Bioscience was purchased by Syngenta in 2012 and Pasteuria is being marketed as a seed treatment for control of H. glycines in 2014 in the north central region. Host-Plant Resistance.  The use of resistant varieties for nematode control related to small acreage specialty crops is underutilized, making the NE-1040 breeding work exceptionally important. Commercial cucurbit rootstocks, cucurbit Plant Introductions, and African horned cucumber (Cucumis metulifer) germplasm lines were evaluated as rootstocks for grafted cantaloupe in a root-knot nematode infested field. Melon and squash hybrid rootstocks were highly susceptible to root-knot. The C. metulifer lines were resistant and were highly compatible rootstocks for grafted cantaloupe. Advanced sweetpotato breeding lines and seedlings from the USDA program were screened for resistance to root-knot nematode. Advanced pepper germplasm lines were screened for resistance to Meloidogyne incognita, and resistant plants were selected for use in a backcross breeding program to develop resistant lines of sweet banana, sweet cherry, and Cubanelle peppers. A broadleaf cigar wrapper type tobacco (B2) developed with single-gene resistance to the tobacco cyst nematode was evaluated for host status to Meloidogyne hapla. Tomato, C9 (cyst nematode susceptible) or the resistant B2 tobacco were inoculated with M. hapla. After 10 weeks, the numbers of galls per pot were less for B2 than tomato and C9. The cyst nematode resistant tobacco may also reduce root-knot populations. The experiment will be repeated. A significant number of sugar beet varieties were available in 2013 for management of H. schachtii in Michigan. They are all, however, BCN tolerant and not BCN resistant. The 2013 SCN resistant variety/seed treatment trial is an excellent example of the development a HG Type two population that can no longer be adequately managed with a PI 88788 derived variety. A new H. glycines resistance blend will be marketed in Michigan for the first time in 2014. Soft-tissue X-ray imaging of the entire root volume of a plant can be captured in a single high-resolution image, allowing sophisticated comparisons of nematode numbers or egg masses with root volume and length. Experiments conducted with reniform nematode (Rotylenchulus reniformis) and resistant or susceptible cotton selections showed that nematode egg masses characteristically appeared on X-rays as hemispheres with a dark basal ring next to the root and a lighter dome, distinct from artifacts such as soil particles and root stubs. Each cotton line had a unique distribution of roots and a unique distribution of nematode feeding sites. The use of X-ray technology and digital image analysis can provide a much more accurate approach to nematode relationships with plant host roots. Cover Crops-Biofuel Crops. - Nine cover crop systems: 1) rye grain +hairy vetch, 2) oat, 3) sudax, 4) forage radish, 5) red clover, 6) rapeseed, 7) buckwheat, 8) wheat, and 9) a weedy fallow control were evaluated in four fields having different management histories and different levels of pathogen pressure and soil quality in relation to changes in the densities of plant-parasitic and free-living nematodes. Total soil populations of plant-parasitic nematodes were highest after wheat, rye/vetch and clover cover crops and lowest after buckwheat, radish and fallow (no cover crop). Tall fescue has been recommended as a preplant cover crop for suppressing plant-parasitic nematode populations in Georgia peach orchards, providing an alternative to chemical pesticide application for management of these plant pathogens. To aid in determining mechanisms of action against nematodes, natural products from tall fescue were tested for activity against root-knot nematodes. Extracts from tall fescue shoots, and extracts and exudates from roots, were found to be nematotoxic and/or nematostatic. Three newly released commercial biofumigation products were evaluated for control of dagger nematodes and compared to a standard practice. The products included two Brassica green manure rotation crops bred and the third was a pelletized rapeseed meal that reportedly contained high levels of glucosinolate promoted as a nitrogen fertilizer treatment. When incorporated into soil as green manure, the biofumigation crops effectively suppressed dagger nematodes but did not outperform the current standard rapeseed Dwarf Essex. Dwarf Essex seed was more available and economical. Pelletized rapeseed meal did not suppress dagger nematodes. Our previous results have indicated that type of glucosinolate may be more important than amount. Field plots infested with Meloidogyne hapla were planted to Pacific Gold brassica, rye or tomato in 2012. In September, Pacific Gold plots were either tilled in or allowed to senesce without tillage. All plots were planted to San Marzano tomato transplants in 2013. Root galls in the tomato bioassay were similar for tomato or Pacific Gold without tillage, as were those planted to the non-host rye crop or tilled (biofumigation) Pacific Gold. Combinations of cover crops (mustard and oil seed radish), rotation crops (corn and soybean), and sugar beet cultivars (nematode-tolerant and susceptible) on have similar effects on parasitic and beneficial nematode communities, crop yield, soil physiochemical changes, and overall soil health. Soil Amendments- Foliar Treatments.  The plant defense stimulator acibenzolar was applied to Lactuca sativa var. Salinas to determine efficacy against Meloidogyne hapla. The material was applied using multiple protocols and application methods but had no effect on nematode galling, compared to infected control plants. Plant parasitic nematodes continue to result in decline of turfgrass health in golf greens as evident by 203 composite soil samples assayed during the 2013 growing season; usually about half of the samples received have damaging populations. The loss of fenamiphos and the lack of alternatives leave golf course superintendents with no control measures. Cultural practices that increase root development are helpful, as is raising the height of cut, allowing the grass to tolerate nematode feeding. Neemix (4.5% azadirachtin), Nemitol (0.42% capsaicin and 3.7% allyl isothiocyanate), Agritrap (potassium mono-phosphate, polysaccharides and surfactants), and Pro-Max (3.5% thyme oil) were tested as all claim to control nematodes. None of the materials had any effect on Tylenchorhynchus or Hoplolaimus nematodes in turf. The nematicide Avid (abamectin) was employed in a number of controlled field studies and trials on golf course putting greens. While results did not demonstrate uniform effectiveness of the material, it did control nematode populations more frequently than any of the other alternative materials used and generally produced significant drops in nematode population when it was effective. Application timing and carrier have a significant impact on efficacy, but it is the most promising turf nematicide since the cancellation of Nemacur and is likely to be accepted by superintendents. Objective 2: Evaluate cultural management procedures for plant-parasitic nematodes in relation to their impacts on the sustainability of soil health: with special research to the utility of nematode community structure as an indicator of overall soil quality and their roles in plant nutrient cycling. Soil Health Management Practices The Michigan Potato Industry Commission has identified soil health as a key limiting factor for the future success of the industry. Soil samples were collected from 96 locations on eight Michigan potato farms for analysis by the Cornell University Soil Health Laboratory. Sites were selected to represent potential high yield, potato early-die and potato scab fields. Samples from woodlots and sites with no history of potato were also included. Available water capacity, soil organic matter, active carbon and mineralizable nitrogen potential were poor; aggregate stability, subsurface hardness, root health and pH were fair, and surface hardness, phosphorus, potassium and minor elements good, resulting in an overall Soil Health Score of 57.8. A Specialty Crop Block Grant was obtained for additional research support. On-going studies on the effects of plant- and animal-based organic and non-organic soil amendment application in mineral soils on carrot quality and yield, soil physiochemical properties, nematode community, and overall soil quality show increased Maturity Index (MI) compared with the controls, suggesting improvement in soil conditions. Nematode Community Structure Analysis.  Roadways have a potential number of ecological effects on adjacent soil communities via physical and chemical alteration of the roadside. The effects of roads by traffic road type (highway, two-lane paved, and gravel) and distance from the road, on soil forest soil nematode communities, was determined in conjunction with chemical and physical measures of soil quality. Spatial patterns of road effects varied by road type, with interactions between road type and both distance and topography. There were differences in all nematode community measures based upon distance as a main effect, as well as some interactions between distance, road type, and topography. Nematode community index values reflect increased disturbance closer to the road, particularly at the shoulder, with later ecological succession and a shift in the decomposer foodweb with increased distance from the road. Gravel roads were the least disturbed nematode community. The ditch and the forest were areas of increased trophic structure, while abundance of plant-parasites was greatest along the roadside. The results suggest that conscious design and management of the forest buffer and intentional inclusion of a ditch as a roadside feature may minimize pollutant movement and protect surrounding landscapes. The effects of coleopteran-active Bt corn on nontarget soil nematodes was evaluated. During the growing season, maturity index values and relative abundance of fungivorous nematodes were greater in Bt than the non-Bt isoline with insecticide and isoline without insecticide, respectively. Nematode trophic diversity values were greater in Bt than non-Bt isoline without insecticide, and this effect continued through the following spring before planting. Abundance of nematode predators increased two weeks after insecticide was applied to non-Bt isoline, but decreased without insecticides on either Bt or the non-Bt isoline. Insecticide appeared to have more non-target effects on nematode communities than Bt. Insecticides temporarily increased relative abundance of predaceous nematodes but eventually reduced successional maturity by harvest. Nematode genera from 3 ecosystems (grassland, cropland, and forest) were analyzed to compare relative magnitude of energy pathways through the soil food web (67 data sets). Bacterial-, fungal- and herbivorous-based energy pathways were compared using abundances or biomass. The patterns of soil energy pathways were similar whether expressed as relative abundance or relative biomass. Relative abundance of bacterivorous nematodes was similar among ecosystems but mean values of biomass were greatest in grassland. In contrast, both relative abundance and biomass of fungivorous nematodes decreased progressively from forest to cropland and grassland ecosystems. The opposite pattern across ecosystems was observed for both relative abundance and biomass of herbivorous nematodes. Energy pathways are bacterial-dominated in all of the ecosystems and fungal and herbivorous pathways are second in dominance in forest and grassland ecosystems, respectively. The relative size of the fungal-based energy pathway suggests a gradient of resource quality among ecosystems. This suggests that herbivorous-based energy pathways are more important in grassland ecosystems than reported previously. Rhabditid nematodes infest earthworm cocoons and destroy developing embryos, presumably by introduction of bacteria that consume the yolk-like food reserve. This relationship may impact soil biodiversity and function by reducing earthworms. Numerous Eisenia fetida cocoons from a compost operation were observed to be infested with nematodes (Oscheius sp.). Many of the adult nematodes contained a fungus inside the nematode intestine. The fungus did not directly harm infected nematodes, implying a non-pathogenic relationship. Identification of the fungus was confirmed with PCR amplification as Sarocladium strictum (= Acremonium strictum). Cultural Management. - Monitoring of plant-parasitic and free-living nematodes continued in 2013 in plots at the long-term Soil Health Site on the Gates Farm near Geneva, NY. This experiment, initiated in 2003, was divided into 72 plots (18 treatments replicated 4 times). The treatments represent no-till, zone-till and plow/conventional-till systems, three cover crops (no cover, rye grain, and vetch), and two crop rotations. One rotation includes high value vegetable crops, whereas the second rotation includes season long soil-building crops. Data collected in 2013 showed an effect of cover crops on soil populations of nematodes, with both free-living and plant-parasitic nematodes higher after vetch. No effect of tillage practices and crop rotation was evident. A Minnesota field study assessed the impact of tillage, fertilizer, and nematicide on plant-parasitic nematodes, nematode community, and corn and soybean yields. Tillage had minor impacts on major plant-parasitic nematode genera. Aldicarb nematicide increased soybean and corn yields under some conditions. Manure strongly enriched the nematode community which also disturbed community structure, while inorganic fertilizers had minimal impact on the nematode community. Intensified tillage increased bacterivore and fungivore populations. Objective 3: Provide educational materials and programs on cultural management of plant-parasitic nematodes based on host resistance, nematode antagonistic rotation or cover crops, soil amendments and biological agents. Two training workshops were provided in 2013 on the stem and bulb nematode (Ditylenchus dipsaci) on garlic, one in Geneva, NY with 38 in attendance and the other in Albany, NY with 40 in attendance. The training workshops and the subsidized diagnostic services provided under this project were funded by a grant from the Specialty Crop Program through the NYS Dept. of Agriculture and Markets. In 2013, over 130 garlic samples were submitted and analyzed for possible infestation by the garlic bloat nematode. The percentage of samples testing positive for the bloat nematode has dropped from 30% in 2010  2011 to less than 10% in late 2012 and 2013. We speculate that this is due to the outreach activities of the program and the management options implemented by garlic producers and industry personnel. In addition, the project leader and cooperators have had extensive correspondence and visits with garlic growers throughout New York and elsewhere on the biology and available management options against the bloat nematode and other diseases and pests of garlic. In preparation for a 2013 soil health presentation at the 109th Annual Meeting of the Washington State Horticultural Association, previous research data from the NE Regional Nematology Project were reanalyzed. It appears that reconstruction of an O-horizon is of significance for increased productivity, soil health and fruit tree health. The data indicate that application of mulch can contribute to this process. A few of the additional outreach activities associated with NE 1040 in 2013 included: Mid-Atlantic Fruit and Vegetable Convention, Hershey PA. Bloat Nematode on garlic and other hosts. January 30, 2013. 30 minutes with 100 growers and industry personnel in attendance. INVITED. Great Lakes Fruit, Vegetable and Farm Market EXPO. Grand Rapids MI. G Abawi, C. Petzoldt, and K. Moktan: Practical Ways to access and manage soil health for disease control and improved yield. December 5, 2013. 45 minutes with 200 in attendance. INVITED A poster was presented to growers on Bloat Nematode (Ditylenchus dipsaci) Infecting Garlic at the Connecticut Vegetable and Small Fruit Growers Conference in Vernon (197 people, January 17, 2013). George Abawi of Cornell-Geneva, J. LaMondia of the CAES and Beth Gugino of Penn State University conducted a day-long SARE-funded workshop on the identification, assessment and management of soilborne plant pathogens in vegetable systems held in Hershey PA (40 people, January 28, 2013). J. LaMondia was interviewed about vegetable pathology and the importance of outreach by Jamie Klein of the Reading Eagle newspaper (January 28, 2013). January 23, 2013 1 hour at the NYSTA Southern Regional Meeting, "Difficult Turf Diseases to Diagnose, Bacteria and Nematodes". February 27, 2013 1 hour at the Western Penn Turf Conference, "Diagnosing and Managing Nematode Problems on Golf Courses without Nemacur" January 15, 2013 1 hour at the Conn GCSA Winter Educational Meeting, "Deciphering Nematode Counts and Managing Nematodes without Nemacur". Milestones Accomplished 2010-2012 All of the 2010-2012 NE 1040 Milestones were accomplished with the following two exceptions: " Continue screening of vegetable germplasm (carrot, onion, pepper, tomato) for resistance to Meloidogyne spp., including M. hapla and lesion nematodes, principally P. penetrans. " Meloidogyne hapla-resistant pepper will be supplied to cooperators and tested against nematode populations in CT, NY and PA. The request for the Material Transfer Agreement to USDA/ARS has been made and the three NE states await approval so that these Milestones can be accomplished. It is anticipated the first one will be achieved in 2013 and the second in 2014. 2013 The following 2013 NE 1040 Milestones were accomplished. Developed and validated integrated nematode management options based on results obtained on effective cover and rotational crops, bio-control agents and resistant crop germ-plasm. Established demonstration trials in experimental and production fields. Evaluated the effectiveness of the established trials of soil management practices on nematode damage and assessed their cost-benefits. Identify whether Brassica seed meals differed in efficacy against target nematodes. Continued outreach activities on nematode damage and management needs.

Atwood, L. W., J. Bingen and G. W. Bird. 2012. Does the Source of Agricultural Management Advice Influence Growers Perception of Problematic Weeds? Poster Session. Annual Meeting of the Weed Science Society of America. Abawi, George S. and Kundan Moktan. 2013. Bloat Nematode: A re-emerging and damaging pest of garlic and other hosts. Proceedings of the Mid-Atlantic Fruit and Vegetable Convention, Hershey, PA held during January 29-31, 2013. Pages 168170. Bao, Y., Chen, S. Y., Vetsch, J., and Randall, G. 2013. Soybean yield and Heterodera glycines responses to liquid swine manure in nematode suppressive soil and conducive soil. Journal of Nematology 45:21-29. Bird, G. W. and J. Smith. 2013. Observations on the Biology of Organic Orchard Soils. Acta Horticulture . 1001:287-293 Bird, G. W. 2012. Nature of Soil Health: With Special Reference to Nematodes. Proceedings of the Annual Meeting of ONRA. Cancun, Mexico. p. 46. Bird. G. 2012. Observations on the Biology of Organic Orchard Soils. Proceedings of the Second International Organic Fruit Research Symposium. Leavenworth, WA. p. 19. Chen, S. Y., Sheaffer, C. C., Wyse, D. L., Nickel, P., and Kandel, H. 2012. Plant-parasitic nematode communities and their associations with soil factors in organically farmed fields in Minnesota. Journal of Nematology 44:361-369. Chen, S., Kurle, J. E., Sun, M., Naeve, S., Wyse, D. L., and Stahl, L. A. 2013. Preceding crops affected iron-deficiency chlorosis and vesicular-arbuscular mycorrhizal fungi in soybean cyst nematode infested fields. Crop Science 53:250-259. doi: 10.2135/cropsci2012.03.0170 Cheng Z., S. Mennan, P.S. Grewal, and H. Melakeberhan 2012. Effects of long-term tillage and rotation the relationship between Heterodera glycines and soil nematode community. 51st Annual Meeting of the Society of Nematologists Meeting, Savannah, Georgia. Grabau, Z., and Chen, S. 2012. Efficacy of organic soil amendments for control of soybean cyst nematode in greenhouse experiments. Journal of Nematology 44:463. Halbrendt, J. and J. A. LaMondia. 2012. Dagger nematodes and perennial fruit crops. Journal of Nematology 44:465. Halbrendt, J.M. 2013. Evaluation of New Commercial Biofumigation Products for Orchard Renovation. Pennsylvania Fruit News 93(1):25-27. Kidane, E., Hu, W., Chen, S., and Neher, D. A. 2012. Ecology of soils suppressive to the soybean cyst nematode: I. effect of tillage and crop-biocide treatments on soil suppressiveness to nematode and soybean yield. Journal of Nematology 44:471. Kidane, E., Hu, W., Chen, S., Liu, X., and Neher, D. A. 2012. Ecology of soils suppressive to the soybean cyst nematode: II. effect of tillage and crop-biocide treatments on nematophagous fungi. Journal of Nematology 44:472. LaMondia, J. A. 2012. Biochar inhibits host recognition by Globodera tabacum. Journal of Nematology 44:473. LaMondia, J. A. 2012. Management of foliar nematodes, Aphelenchoides fragariae, in ornamentals. www.apsnet.org/meetings/Documents/2012_Meeting_Abstracts/aps12abP202.htm. Melakeberhan, H., Douches, D. and Wang, W. 2012. Interactions of selected potato cultivars and populations of Meloidogyne hapla adapted to the US Midwest soils. Crop Science, 52:1-6. Melakeberhan, H., A. Kravchenko, and K. Thelen 2012. Effects of Agronomic practices on the establishment of Heterodera glycines in virgin land. 51st Annual Meeting of the Society of Nematologists Meeting, Savannah, Georgia. Melakeberhan, H. and Wang, W. 2012. Suitability of celery cultivars to populations of Meloidogyne hapla. Nematology, 14:623-629. Meyer, S.L.F., Nyczepir, A.P., Rupprecht, S.M., Mitchell, A.D., Martin, P.A., Brush, C.W., Chitwood, D.J., Vinyard, B.T. 2013. Tall fescue Jesup (Max-Q): Meloidogyne incognita development in roots and nematotoxicity. Agronomy Journal 105(3):755-763. Neher, D.A., Weicht, T.R., Bates, S.T., Leff, J.W., and Fierer, N. Changes in bacterial and fungal communities across compost recipes, preparation methods, and composting times. PloS ONE DOI 10.1371/journal.pone.0079512 Nishanthan, T., Neher, D. A., and Chen, S. 2012. Ecology of soils suppressive to the soybean cyst nematode: III. association of nematode and microbial communities with the soil suppressiveness . Journal of Nematology 44:482. Zalom, F., B. Tashpulatova, R. Maulvanova, G. Bird and K. Maridia. 2012. IPM Packages for Central Asia. Proc. 7th Int. IPM Symposium. Mar 27-29, Memphis TN. Abstr. 25.7. Zhao, J., and Neher, D.A. 2012. Soil nematode genera that predict specific types of disturbance. Applied Soil Ecology 64: 135-141. Zhu, Y., Shi, F., Tian, J., Liu, J., Chen, S., Xiang, M., and Liu, X. 2013. Effect of soybean monoculture on the bacterial communities associated with cysts of Heterodera glycines. Journal of Nematology 45:228-235.