SAES-422 Multistate Research Activity Accomplishments Report
Sections
Status: Approved
Basic Information
- Project No. and Title: W186 : Genetic Variability in the Cyst and Root-Knot Nematodes
- Period Covered: 01/01/2002 to 12/01/2002
- Date of Report: 09/30/2003
- Annual Meeting Dates: 11/08/2002 to 11/09/2002
Participants
Robert Riggs - University of Arkansas; Edward Caswell-Chen - University of California, Davis; Phil Roberts - University of California, Riverside; Bradley Hyman - University of California, Riverside; Brent Sipes - University of Hawaii; Saad Hafez - University of Idaho; Haddish Malakeberan - Michigan State University; Tom Powers - University of Nebraska; Steve Thomas - New Mexico State University; Ken Barker - North Carolina State University; Russ Ingham - Oregon State University; Pat Donald - USDA-ARS (South Area Crop Genetics and Production Research Unit,TN); Ekaterina Riga - Washington State University; Fred Gray - University of Wyoming; Don Cooksey - Administrative Advisor, University of California, Riverside
[Minutes]
Accomplishments
The goal of W-186 is to fulfil the need for alternative, integrated nematode management through the discovery and development of alternatives to chemical-based soil pathogen and nematode control. This regional project was initiated because the membership recognized the increasing importance of characterizing the genetic variation in nematode populations and understanding how that variation influences the success of alternative nematode management strategies. There are three objectives in the current project: Objective 1: Characterize genetic variability as related to plant parasitic nematode responses to resistance, environment, biological processes, and morphology. Objective 2: Determine nematode fitness and adaptability relative to environment, host plant, and host plant resistance. Objective 3: Design and develop management strategies for cyst and root-knot nematodes relative to genetic variability.
Diagnostic test development: In Washington molecular tests for identification of races of Meloidogyne chitwoodi are under development. A two-marker identification system for M. chitwoodi species identification has been tested in Nebraska and applied in a large-scale survey of potato production areas. The multi-state survey for Meloidogyne and Globodera species recovered no nematodes of quarantine significance in Texas, Kansas, Nebraska, Colorado, Wyoming, or North Dakota. Results are available at the National Agricultural Pest Information System (http://www.ceris.purdue.edu/napis/). Paratrichodorus carrying virulent virus particles are the focus of additional diagnostic tests in Washington. Evolutionary relationships based on nucleotide variation within the D3 rDNA region were examined among seven California and other Meloidogyne hapla isolates and seven isolates of apopmictic M. arenaria, M. incognita and M. javanica; a 3 bp insertion distinguished automictic M. hapla from the apopmictic isolates.
Nematode population dynamics: In New Mexico the interaction between root-knot nematodes (Meloidogyne species) reproducing on purple and yellow nutsedge and those reproducing on chile pepper was examined in a series of field experiments. Results indicate the presence of nutsedge in chile fields negatively affects root-knot reproduction on chile. Preliminary results measuring differential rates of infection suggest inoculum source may play a role in root-knot nematode infectivity. Population dynamics of Meloidogyne chitwoodi with respect to degree-day accumulation were studied in Oregon and Colorado. Subtle differences were observed among data sets from Oregon, Colorado, Washington, and Idaho, although the general patterns remained the same. Results reaffirm the need for well-timed application of nematicides for maximum efficacy. The relationship between soybean cyst nematode populations and soil pH is a component of ongoing research in Michigan as well as cyst management using a municipal sewage compost mixture.
Nematode suppression: Successful suppression of root-knot populations was achieved by planting root-knot resistant alfalfa prior to chile in New Mexico. In addition to the suppression of nematodes due to nematode resistance, alfalfa had the added benefit of reducing nutsedge populations that serve as a reservoir host for Meloidogyne. A range of crop rotation sequences for controlling M. chitwoodi is being tested in Oregon. In Wyoming, trap crops for the sugar beet cyst nematode are being developed as a key management strategy. Work with the resistant sugar beet cultivar Nematop was discontinued due to the beets lack of resistance to Beet curly top virus. Germplasm from Nematop is being used in a new effort to breed nematode resistant beets. Multiyear high-resolution sampling was conducted two fields to determine if hot spots of nematode infestation change annually. Sampling indicated consistency across years suggesting spot treatment may be accurately applied in successive years based on a single sampling. In Washington, a new biological nematicide is being tested.
Genetic variability and host resistance: Root-knot nematode (Meloidogyne spp.) interactions with resistance in the host crops cowpea, tomato (Lycopersicon esculentum and L. peruvianum) and common bean interactions are being used to analyze genetic variability in nematodes for (a)virulence expression and stability. Resistance is being used both in commercial crop cultivars and in cover crop plantings for control of root-knot in many crops. New resistance sources have been identified that confer unique specificities that match avirulence genes in the nematode. Selection for virulence in nematode populations has been shown to occur both naturally in fields planted with resistant cultivars and also in the laboratory by experimental manipulation. Durability of resistance is dependent upon utilization of multiple sources of resistance in cropping systems. Analysis of the Rk locus in cowpea that confers resistance to M. incognita and M. javanica revealed at least four allelic or tandem gene forms. Each of these R gene forms has a unique level of resistance expression and is effective against different populations of M. incognita and M. javanica. The Rk locus was placed on the improved genetic map for cowpea, and is located at the bottom of linkage group one. A search for markers closely linked to the Rk gene is being made using AFLP analysis with bulked segregants from a recombinant inbred line population. Virulence in M. incognita to gene Rk was shown to be a heritable trait and can be selected from some but not all individual avirulent nematode lines when inoculated onto resistant plants. In common bean, differential interactions between isolates of M. hapla race A for ability to reproduce on bean plants with a dominant resistance gene were used to analyze genetics of virulence to this R gene. Segregation of avirulence in F3 to F5 nematode families derived from crosses between avirulent and virulent M. hapla parent lines indicated a single gene control of this trait, with avirulence dominant to virulence (recessive).
Diagnostic test development: In Washington molecular tests for identification of races of Meloidogyne chitwoodi are under development. A two-marker identification system for M. chitwoodi species identification has been tested in Nebraska and applied in a large-scale survey of potato production areas. The multi-state survey for Meloidogyne and Globodera species recovered no nematodes of quarantine significance in Texas, Kansas, Nebraska, Colorado, Wyoming, or North Dakota. Results are available at the National Agricultural Pest Information System (http://www.ceris.purdue.edu/napis/). Paratrichodorus carrying virulent virus particles are the focus of additional diagnostic tests in Washington. Evolutionary relationships based on nucleotide variation within the D3 rDNA region were examined among seven California and other Meloidogyne hapla isolates and seven isolates of apopmictic M. arenaria, M. incognita and M. javanica; a 3 bp insertion distinguished automictic M. hapla from the apopmictic isolates.
Nematode population dynamics: In New Mexico the interaction between root-knot nematodes (Meloidogyne species) reproducing on purple and yellow nutsedge and those reproducing on chile pepper was examined in a series of field experiments. Results indicate the presence of nutsedge in chile fields negatively affects root-knot reproduction on chile. Preliminary results measuring differential rates of infection suggest inoculum source may play a role in root-knot nematode infectivity. Population dynamics of Meloidogyne chitwoodi with respect to degree-day accumulation were studied in Oregon and Colorado. Subtle differences were observed among data sets from Oregon, Colorado, Washington, and Idaho, although the general patterns remained the same. Results reaffirm the need for well-timed application of nematicides for maximum efficacy. The relationship between soybean cyst nematode populations and soil pH is a component of ongoing research in Michigan as well as cyst management using a municipal sewage compost mixture.
Nematode suppression: Successful suppression of root-knot populations was achieved by planting root-knot resistant alfalfa prior to chile in New Mexico. In addition to the suppression of nematodes due to nematode resistance, alfalfa had the added benefit of reducing nutsedge populations that serve as a reservoir host for Meloidogyne. A range of crop rotation sequences for controlling M. chitwoodi is being tested in Oregon. In Wyoming, trap crops for the sugar beet cyst nematode are being developed as a key management strategy. Work with the resistant sugar beet cultivar Nematop was discontinued due to the beets lack of resistance to Beet curly top virus. Germplasm from Nematop is being used in a new effort to breed nematode resistant beets. Multiyear high-resolution sampling was conducted two fields to determine if hot spots of nematode infestation change annually. Sampling indicated consistency across years suggesting spot treatment may be accurately applied in successive years based on a single sampling. In Washington, a new biological nematicide is being tested.
Genetic variability and host resistance: Root-knot nematode (Meloidogyne spp.) interactions with resistance in the host crops cowpea, tomato (Lycopersicon esculentum and L. peruvianum) and common bean interactions are being used to analyze genetic variability in nematodes for (a)virulence expression and stability. Resistance is being used both in commercial crop cultivars and in cover crop plantings for control of root-knot in many crops. New resistance sources have been identified that confer unique specificities that match avirulence genes in the nematode. Selection for virulence in nematode populations has been shown to occur both naturally in fields planted with resistant cultivars and also in the laboratory by experimental manipulation. Durability of resistance is dependent upon utilization of multiple sources of resistance in cropping systems. Analysis of the Rk locus in cowpea that confers resistance to M. incognita and M. javanica revealed at least four allelic or tandem gene forms. Each of these R gene forms has a unique level of resistance expression and is effective against different populations of M. incognita and M. javanica. The Rk locus was placed on the improved genetic map for cowpea, and is located at the bottom of linkage group one. A search for markers closely linked to the Rk gene is being made using AFLP analysis with bulked segregants from a recombinant inbred line population. Virulence in M. incognita to gene Rk was shown to be a heritable trait and can be selected from some but not all individual avirulent nematode lines when inoculated onto resistant plants. In common bean, differential interactions between isolates of M. hapla race A for ability to reproduce on bean plants with a dominant resistance gene were used to analyze genetics of virulence to this R gene. Segregation of avirulence in F3 to F5 nematode families derived from crosses between avirulent and virulent M. hapla parent lines indicated a single gene control of this trait, with avirulence dominant to virulence (recessive).
Impacts
- The characterization and identification of genetic variability in nematodes in response to management alternatives and environment are helping to guide decisions on the use of various control tactics.
- For example, decisions on the use of resistant crop varieties, on rotations, cover and trap cropping and soil amendments are being improved by incorporating knowledge of nematode genetics and biology into the decision making process.
Publications
Ammiraju, J. S. S., J. C. Veremis, X. Huang, P. A. Roberts and I. Kaloshian. 2003. The heat-stable root-knot nematode resistance gene Mi-9 from Lycopersicon peruvianum is localized on the short arm of chromosome 6. Theor. Appl. Genet. 106:478-484.
Avendano, F., O. Schabenberger, F.J. Pierce and H. Melakeberhan. (2003). Geostatistical analysis of field spatial distribution patterns of the soybean cyst nematode, Heterodera glycines. Agronomy Journal, 00. In press.
Avendano, F., F. J. Pierce, O. Schabenberger, and H. Melakeberhan (2002). The relationship between soil type and soil texture with spatial distribution of Heterodera glycines. Nematology, 4: 250.
Boiteux, L.S., I.C. Bach, M.E.N. Fonseca, A.W. Moita, W.C. Matthews, P.A. Roberts, and P.W. Simon. 2003. Evidence for a dosage-dependent response of the Meloidogyne javanica resistance locus in carrot via linkage analysis with codominant flanking markers. Euphytica. (in press).
Bosland, P. W., Y Zewdie, and S. H. Thomas. 2003. NuMex Nematador: Southern root-knot nematode resistant cayenne. HortScience 38: in press.
Chen, P. and P.A. Roberts. 2003. Virulence in Meloidogyne hapla differentiated by resistance in common bean (Phaseolus vulgaris). Nematology 5:39-47.
Chen, P., P. A. Roberts, A. E. Metcalf, and B. C. Hyman. 2003. Nucleotide substitution patterning within the Meloidogyne rDNA D3 region and its evolutionary implications. Journal of Nematology, in press.
Ehlers, J.D., W.C. Matthews, A.E. Hall, and P.A. Roberts. 2002. Breeding and Evaluation of Cowpeas with High Levels of Broad-based Resistance to Root-knot Nematodes. Pg. 41-51 In: Proceedings of the Third World Cowpea Conference, IITA, Ibadan, Nigeria.
Gray, F.A. 2003. Alfalfa disease management. University of Wyoming, Agricultural Experiment Station Bulletin B-1136, pp 1-40.
Gray, F.A. and G.D. Griffin. 2002. Plant parasitic nematodes of alfalfa in the United States. 2002. Proceedings of the 28th North American Alfalfa Improvement Conference, Sacramento, CA. p. 69.
Gray, F.A. and D.W. Koch. 2002. Trap Crops. Pp. 852-854 In: Cultural Practices, Encyclopedia of Pest Management. Marcel Dekker, Inc., NY.
Gray, F.A., D.W. Koch, H.J. Smith, L.J. Held and J.M. Krall. 2003. Controlling the sugarbeet nematode (Heterodera schachtii) in the U.S.A., p. 251, Proceedings of the 2003 International Congress of Plant Pathology, Christchurch, New Zealand, Feb. 2-7.
Hafez, S.L. and P. Sundararaj. 2002. Integrated nematode management options for the sustainable potato production. Proceedings of the University of Idaho Winter Commodity Schools 2002 . 111-116.
Hafez, S.L. and P. Sundararaj. 2002. Sugarbeet cyst nematode management options in Idaho. Proceedings of the University of Idaho Winter Commodity Schools 2002. 231-236.
Hafez, S. L. and P. Sundararaj. 2002. Screening bean cultivars to Meloidogyne Chitwoodi and M. hapla as an option for nematode management in potato fields. Presented at the Sixth conference of Applied Zoologists Research Association on Advances in Applied Zoological Researches for Food Production and Environmental safety held in Cuttack, India from December 19 22.
Hafez, S. L. and P. Sundararaj. 2002. Impact of oil radish and white mustard for the effective sugar beet cyst nematode management. Presented at the Sixth conference of Applied Zoologists Research Association on Advances in Applied Zoological Researches for Food Production and Environmental safety held in Cuttack, India from December 19 22.
Hafez, S. L. and P. Sundararaj. 2002. Nematode diversity and agricultural sustainability in Idaho. Presented at the Sixth conference of Applied Zoologists Research Association on Advances in Applied Zoological Researches for Food Production and Environmental safety held in Cuttack, India from December 19 22.
Hafez, S. L. and P. Sundararaj. 2002. Chemical options for the management of Heterodera schachtii in sugar beet under field conditions. Hafez, S. L. and P. Sundararaj. Presented at the Fourth International Congress of Nematology (FICN) held at Canary Islands, Spain June 8 13, 2002. Also abstract published in the Journal Nematology. 4 :1, 295.
Hafez, S. L. and P. Sundararaj. 2002. Evaluation of nematicides for the management of Meloidogyne chitwoodi on potato in Idaho. Presented at the Fourth International Congress of Nematology (FICN) held at Canary Islands, Spain June 8 13, 2002. Also abstract published in the Journal Nematology. 4 :1, 295-296.
Hafez, S. L. and P. Sundararaj. 2002. Comparative efficacy of fosthiazate formulations for the mangement of Meloidogyne chitwoodi. Hafez, S. L. and P. Sundararaj. Presented at the Fourth International Congress of Nematology (FICN) held at Canary Islands, Spain June 8 13, 2002. Also abstract published in the Journal Nematology. 4 :1, 296.
Hafez, S.L., G. Haroutunian, R. Khoury, and P. Sundararaj. 2002. Preliminary report on the methyl bromide complete phaseout investment project in Lebanon. Proceedings of the Annual International Conference on Methyl bromide alternatives and emission reductions held on Novemebr 6-8, 2002 at Orlando, Florida. 11-1 to 11-2, 2002.
Hafez, S.L., P. Sundararaj and D. Miller. 2002. Reaction of twenty-one alfalfa cultivars to the lesion nematode Pratylenchus penetrans and the root - knot nematode Meloidogyne chitwoodi. Proceedings of the North American Alfalfa Improvement Conference held at Sacramento, California from July 27 to 31, 2002.
Hafez, S.L., P. Sundararaj and Gale W. Harding. 2002. Efficacy of placement of aldicarb for the control of stubby root nematodes and corky ring spot disease of potato. Nematologia Mediterranea. 30 : 227 - 229.
Hafez, S.L. and P. Sundararaj. 2002. Evaluation of autumn or spring application of Ethoprop for the management of Meloidogyne chitwoodi on potato. Nematologia Mediterranea. 30 : 159 - 161.
Hafez, S.L. and P. Sundararaj. 2002. Efficacy of seed crop meals for the management of Heterodera schachtii and Meloidogyne chitwoodi in pots. Nematologia Mediterranea. 30 : 181 - 183.
Hafez, S.L. and P. Sundararaj. 2002. Efficacy of chemical nematicides for the management of Meloidogyne chitwoodi on potato. 2002. International Journal of Nematology. 12 : 76 - 78.
Hafez, S.L. and P. Sundararaj. 2002. Chemical options for the management of stubby root nematodes on potato. 2002. International Journal of Nematology. 12 : 73 - 75.
Hafez, S.L., P. Sundararaj and B. A. Hatjian. 2002. Fosthiazate 500 EC for control of Columbia root-knot nematode in potato, 2000. 2002. Fungicide and Nematicide Tests. 57:11.
Hafez, S.L., P. Sundararaj and R. Portenier. 2002. Application and placement of Temik, Vydate and Admire for control of stubby root nematode and corky ringspotdisease of potato, 1999. Fungicide and Nematicide Tests. 57:9.
Hafez, S.L., P. Sundararaj and R. Portenier. 2002. Fosthiazate 900 EC for control of Columbia root-knot nematode in potato, 1998. Fungicide and Nematicide Tests. 57:12.
Hall, A.E., N. Cisse, S. Thiaw, H.O.A. Elawad, J.D. Ehlers, A.M. Ismail, R.L. Fery, P.A. Roberts, L.W. Kitch, L.L. Murdock, O. Boukar, R.D. Phillips and K.H. McWatters. 2003. Development of Cowpea Cultivars and Germplasm. Field Crops Res. 82:103-134.
Hurchanik, D., D.P. Schmitt, N.V. Hue, and B.S. Sipes. 2003. Relationship of Meloidogyne konaensis population densities to nutritional status of coffee roots and leaves. Nematropica 33: in press.
McSorley, R.L. and S.H. Thomas. 2003. Diseases caused by nematodes. Pp. 46-49. In: Compendium of Pepper Diseases. K. Pernezy, P. D. Roberts, J. F. Murphy, and N. P. Goldberg, eds., APS Press. St. Paul, MN.
Melakeberhan, H. (2002). Embracing the Emerging Precision Agriculture Technologies for Site-specific Management of Yield-limiting factors. Journal of Nematology, 34: 185-188.
Melakeberhan, H. (2003). Physiological interaction between nematodes and their host plants. In: Z.X. Chen, S. Y. Chen, and D. W. Dickson (eds.) Nematology, Advances and Perspectives. Volume I: Nematode Morphology, Physiology, and Ecology. Frontiers of Science and Technology for the 21st Century" Series. Tsinghua University Press, China. In press.
Melakeberhan, H. and J. Dey. (2003). Competition between Heterodera glycines and Meloidogyne incognita or Pratylenchus penetrans: Independent infection rate measurements. Journal of Nematology, 35: In press.
Ouedraogo, J.T., B.S. Gowda, M. Jean, T.J. Close, J.D. Ehlers, A.E. Hall, A.G. Gillaspie, P.A. Roberts, A.M. Ismail, G. Bruening, P. Gepts, M.P. Timko and F.J. Belzile. 2002. An improved genetic map for Cowpea (Vigna unguiculata L.) combining AFLP, RFLP, RAPD and biochemical markers and biological resistance traits. Genome 45: 175-188.
Riga, E., Mojtahedi, H., Ingham R. e. & A. M. McGuire. (2003). Green manure
amendments and management of root knot nematodes on potato in the Pacific Northwest of USA. Nematology. (In press)
Mojtahedi, H., Boydston, R. A., Thomas, P. E., Crosslin, J., M Santo, G. S., Riga, E., & T. L. Anderson. 2003. Weed Hosts of Paratrichodorus allius and Tobacco Rattle Virus in the Pacific Northwest. American Journal of Potato Research. (In Press).
Roberts, P.A. 2002. Concepts and Consequences of Resistance. Pages 23-41 In: Plant Resistance to Parasitic Nematodes (J.L. Starr, R. Cook and J. Bridge, eds.) CAB International: Wallingford, UK.
Schroeder, J., S. H. Thomas and L. W. Murray. 2003. Root-knot-nematodes affect annual and perennial weed interactions with chile pepper. Weed Science 51: in press.
Tsang, M.M.C., A.H. Hara and B.S. Sipes. 2003. Hot-water treatments of potted palms to
control burrowing nematode, Radopholus similis. Crop Protection 22:589-593.
Wang, K.H., B. S. Sipes, and D. P. Schmitt. 2002. Crotalaria as a cover crop for nematode management: a review. Nematropica 32:35-57.
Wang, K.H., B. S. Sipes, and D. P. Schmitt. 2002. Management of Rotylenchulus reniformis in pineapple, Ananas comosus, by intercycle cover crops. Journal of Nematology 34:106-114.
Wang, K. H., B. S. Sipes, and D. P. Schmitt. 2003. Enhancement of Rotylenchulus reniformis suppressiveness by Crotalaria juncea amendment in pineapple soils. Agriculture, Ecosystems and Environment 94:197-203.
Avendano, F., O. Schabenberger, F.J. Pierce and H. Melakeberhan. (2003). Geostatistical analysis of field spatial distribution patterns of the soybean cyst nematode, Heterodera glycines. Agronomy Journal, 00. In press.
Avendano, F., F. J. Pierce, O. Schabenberger, and H. Melakeberhan (2002). The relationship between soil type and soil texture with spatial distribution of Heterodera glycines. Nematology, 4: 250.
Boiteux, L.S., I.C. Bach, M.E.N. Fonseca, A.W. Moita, W.C. Matthews, P.A. Roberts, and P.W. Simon. 2003. Evidence for a dosage-dependent response of the Meloidogyne javanica resistance locus in carrot via linkage analysis with codominant flanking markers. Euphytica. (in press).
Bosland, P. W., Y Zewdie, and S. H. Thomas. 2003. NuMex Nematador: Southern root-knot nematode resistant cayenne. HortScience 38: in press.
Chen, P. and P.A. Roberts. 2003. Virulence in Meloidogyne hapla differentiated by resistance in common bean (Phaseolus vulgaris). Nematology 5:39-47.
Chen, P., P. A. Roberts, A. E. Metcalf, and B. C. Hyman. 2003. Nucleotide substitution patterning within the Meloidogyne rDNA D3 region and its evolutionary implications. Journal of Nematology, in press.
Ehlers, J.D., W.C. Matthews, A.E. Hall, and P.A. Roberts. 2002. Breeding and Evaluation of Cowpeas with High Levels of Broad-based Resistance to Root-knot Nematodes. Pg. 41-51 In: Proceedings of the Third World Cowpea Conference, IITA, Ibadan, Nigeria.
Gray, F.A. 2003. Alfalfa disease management. University of Wyoming, Agricultural Experiment Station Bulletin B-1136, pp 1-40.
Gray, F.A. and G.D. Griffin. 2002. Plant parasitic nematodes of alfalfa in the United States. 2002. Proceedings of the 28th North American Alfalfa Improvement Conference, Sacramento, CA. p. 69.
Gray, F.A. and D.W. Koch. 2002. Trap Crops. Pp. 852-854 In: Cultural Practices, Encyclopedia of Pest Management. Marcel Dekker, Inc., NY.
Gray, F.A., D.W. Koch, H.J. Smith, L.J. Held and J.M. Krall. 2003. Controlling the sugarbeet nematode (Heterodera schachtii) in the U.S.A., p. 251, Proceedings of the 2003 International Congress of Plant Pathology, Christchurch, New Zealand, Feb. 2-7.
Hafez, S.L. and P. Sundararaj. 2002. Integrated nematode management options for the sustainable potato production. Proceedings of the University of Idaho Winter Commodity Schools 2002 . 111-116.
Hafez, S.L. and P. Sundararaj. 2002. Sugarbeet cyst nematode management options in Idaho. Proceedings of the University of Idaho Winter Commodity Schools 2002. 231-236.
Hafez, S. L. and P. Sundararaj. 2002. Screening bean cultivars to Meloidogyne Chitwoodi and M. hapla as an option for nematode management in potato fields. Presented at the Sixth conference of Applied Zoologists Research Association on Advances in Applied Zoological Researches for Food Production and Environmental safety held in Cuttack, India from December 19 22.
Hafez, S. L. and P. Sundararaj. 2002. Impact of oil radish and white mustard for the effective sugar beet cyst nematode management. Presented at the Sixth conference of Applied Zoologists Research Association on Advances in Applied Zoological Researches for Food Production and Environmental safety held in Cuttack, India from December 19 22.
Hafez, S. L. and P. Sundararaj. 2002. Nematode diversity and agricultural sustainability in Idaho. Presented at the Sixth conference of Applied Zoologists Research Association on Advances in Applied Zoological Researches for Food Production and Environmental safety held in Cuttack, India from December 19 22.
Hafez, S. L. and P. Sundararaj. 2002. Chemical options for the management of Heterodera schachtii in sugar beet under field conditions. Hafez, S. L. and P. Sundararaj. Presented at the Fourth International Congress of Nematology (FICN) held at Canary Islands, Spain June 8 13, 2002. Also abstract published in the Journal Nematology. 4 :1, 295.
Hafez, S. L. and P. Sundararaj. 2002. Evaluation of nematicides for the management of Meloidogyne chitwoodi on potato in Idaho. Presented at the Fourth International Congress of Nematology (FICN) held at Canary Islands, Spain June 8 13, 2002. Also abstract published in the Journal Nematology. 4 :1, 295-296.
Hafez, S. L. and P. Sundararaj. 2002. Comparative efficacy of fosthiazate formulations for the mangement of Meloidogyne chitwoodi. Hafez, S. L. and P. Sundararaj. Presented at the Fourth International Congress of Nematology (FICN) held at Canary Islands, Spain June 8 13, 2002. Also abstract published in the Journal Nematology. 4 :1, 296.
Hafez, S.L., G. Haroutunian, R. Khoury, and P. Sundararaj. 2002. Preliminary report on the methyl bromide complete phaseout investment project in Lebanon. Proceedings of the Annual International Conference on Methyl bromide alternatives and emission reductions held on Novemebr 6-8, 2002 at Orlando, Florida. 11-1 to 11-2, 2002.
Hafez, S.L., P. Sundararaj and D. Miller. 2002. Reaction of twenty-one alfalfa cultivars to the lesion nematode Pratylenchus penetrans and the root - knot nematode Meloidogyne chitwoodi. Proceedings of the North American Alfalfa Improvement Conference held at Sacramento, California from July 27 to 31, 2002.
Hafez, S.L., P. Sundararaj and Gale W. Harding. 2002. Efficacy of placement of aldicarb for the control of stubby root nematodes and corky ring spot disease of potato. Nematologia Mediterranea. 30 : 227 - 229.
Hafez, S.L. and P. Sundararaj. 2002. Evaluation of autumn or spring application of Ethoprop for the management of Meloidogyne chitwoodi on potato. Nematologia Mediterranea. 30 : 159 - 161.
Hafez, S.L. and P. Sundararaj. 2002. Efficacy of seed crop meals for the management of Heterodera schachtii and Meloidogyne chitwoodi in pots. Nematologia Mediterranea. 30 : 181 - 183.
Hafez, S.L. and P. Sundararaj. 2002. Efficacy of chemical nematicides for the management of Meloidogyne chitwoodi on potato. 2002. International Journal of Nematology. 12 : 76 - 78.
Hafez, S.L. and P. Sundararaj. 2002. Chemical options for the management of stubby root nematodes on potato. 2002. International Journal of Nematology. 12 : 73 - 75.
Hafez, S.L., P. Sundararaj and B. A. Hatjian. 2002. Fosthiazate 500 EC for control of Columbia root-knot nematode in potato, 2000. 2002. Fungicide and Nematicide Tests. 57:11.
Hafez, S.L., P. Sundararaj and R. Portenier. 2002. Application and placement of Temik, Vydate and Admire for control of stubby root nematode and corky ringspotdisease of potato, 1999. Fungicide and Nematicide Tests. 57:9.
Hafez, S.L., P. Sundararaj and R. Portenier. 2002. Fosthiazate 900 EC for control of Columbia root-knot nematode in potato, 1998. Fungicide and Nematicide Tests. 57:12.
Hall, A.E., N. Cisse, S. Thiaw, H.O.A. Elawad, J.D. Ehlers, A.M. Ismail, R.L. Fery, P.A. Roberts, L.W. Kitch, L.L. Murdock, O. Boukar, R.D. Phillips and K.H. McWatters. 2003. Development of Cowpea Cultivars and Germplasm. Field Crops Res. 82:103-134.
Hurchanik, D., D.P. Schmitt, N.V. Hue, and B.S. Sipes. 2003. Relationship of Meloidogyne konaensis population densities to nutritional status of coffee roots and leaves. Nematropica 33: in press.
McSorley, R.L. and S.H. Thomas. 2003. Diseases caused by nematodes. Pp. 46-49. In: Compendium of Pepper Diseases. K. Pernezy, P. D. Roberts, J. F. Murphy, and N. P. Goldberg, eds., APS Press. St. Paul, MN.
Melakeberhan, H. (2002). Embracing the Emerging Precision Agriculture Technologies for Site-specific Management of Yield-limiting factors. Journal of Nematology, 34: 185-188.
Melakeberhan, H. (2003). Physiological interaction between nematodes and their host plants. In: Z.X. Chen, S. Y. Chen, and D. W. Dickson (eds.) Nematology, Advances and Perspectives. Volume I: Nematode Morphology, Physiology, and Ecology. Frontiers of Science and Technology for the 21st Century" Series. Tsinghua University Press, China. In press.
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