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David Gent
Office/Lab: USDA/Forage Seed and Cereal Research Unit |
Integrated pest management; downy and powdery mildew of hop
Our research centers around developing integrated management systems for hop that reduce chemical inputs for downy and powdery mildew through disease forecasting, modification of cultural practices, and host resistance. The overall goal of our research is to develop disease management strategies that reduce production costs and improve grower profitability and sustainability.
Nanci Adair
Melanie Mitchell
Joanna Woods
http://www.ars.usda.gov/pandp/people/people.htm?personid=37109
Pethybridge, S. J., Gent, D. H., Esker, P. D., Turechek, W. W., Hay, F. S., and Nutter, F. W., Jr. 2008. Site-specific risk factors for ray blight in Tasmanian pyrethrum fields. Plant Dis. Submitted.
Smith, J. A., Gent , D. H., Henning, J. A., Mahaffee, W. F., Ocamb, C. M., and Hummer, K. E. 2008. Notice of release of powdery mildew resistant Humulus lupulus var. lupulus germplasm accession 'Kazak 2000'. USDA-ARS Germplasm Release. Submitted .
Gent, D. H., James, D. G., Wright, L. C., Barbour, J. D., Dreves, A. J., Fisher, G. C., and Walton, V. M. 2008. Effects of powdery mildew fungicide programs on twospotted spider mite (Acari: Tetranychidae), hop aphid (Homoptera: Aphididae), and their natural enemies in hop yards. J. Econ. Entomol. In press.
Gent , D. H., Turechek, W. W., and Mahaffee, W. F. 2008. Spatial and temporal stability of the parameters of the binary power law. Phytopathology 98:1107-1117.
Pethybridge, S. J., Hay, F. S., Esker, P. D., Gent, D. H., Wilson, C. R., and Nutter, F. W., Jr. 2008. Diseases of pyrethrum in Tasmania : Challenges and prospects for management. Plant Dis. 92:1260-1272.
Gent, D. H., Nelson, M. E., George, A. E., Grove, G. G., Mahaffee, W. F., Ocamb, C. M., Barbour, J. D., Peetz, A., and Turechek, W. W. 2008. A decade of hop powdery mildew in the pacific northwest. Online. Plant Health Progress doi:10.1094/PHP-2008-0314-01-RV.
Gent , D. H., Nelson, M. E., and Grove, G. G. 2008. Persistence of phenylamide insensitivity in Pseudoperonospora humuli . Plant Dis. 92:463-468.
Henning, J. A., Haunold, A., Townsend, M. S., Gent , D. H., and Parker, T. P. 2008. Registration of 'Teamaker' hop. J. Plant Registrations 2: 13-14.
Walton, V. M., Dreves, A. J., Gent, D. H., James, D. G., Martin, R. R., Chambers, U., and Skinkis, P. A. 2007. Relationship between rust mites Calepitrimerus vitis (Nalepa), bud mites Colomerus vitis (Pagenstecher) (Acari: Eriophyidae) and short shoot syndrome in Oregon vineyards. Internat. J. Acarol. 33:307-318.
Gent , D. H., Turechek, W. W., and Mahaffee, W. F. 2007. Sequential sampling for estimation and classification of the incidence of hop powdery mildew I: Leaf sampling. Plant Dis. 91:1002-1012.
Gent , D. H., Turechek, W. W., and Mahaffee, W. F. 2007. Sequential sampling for estimation and classification of the incidence of hop powdery mildew II: Cone sampling. Plant Dis. 91:1013-1020.
Lang, J. M., Gent , D. H., and Schwartz, H. F. 2007. Management of Xanthomonas leaf blight of onion with h-mutant bacteriophages and a plant activator . Plant Dis. 91:871-878
Gent , D. H., Martin, R. R., and Ocamb, C. M. 2007. First report of Iris yellow spot viru s on onion and leek crops in western Oregon . Plant Dis. 91:468.
Gent, D. H., du Toit, L. J., Fichtner, S. F., Mohan, S. K., Pappu, H. R., and Schwartz, H. F. 2006. Iris yellow spot virus : An emerging threat to onion bulb and seed production. Plant Dis. 90:1469-1480.
Gent , D. H., Mahaffee, W. F., and Turechek, W. W. 2006. Spatial heterogeneity of the incidence of powdery mildew in hop cones. Plant Dis. 90:1433-1440.
Gent , D. H., and Schwartz, H. F. 2005. Effect of nitrogen fertilization and seed contamination on epiphytic populations of Xanthomonas axonopodis pv. allii and development of Xanthomonas leaf blight of onion. Online. Plant Health Progress doi:10.1094/PHP-2005-0331-01-RS.
Gent , D. H., and Schwartz, H. F. 2005. Management of Xanthomonas leaf blight of onion with a plant activator, biological control agents, and copper bactericides. Plant Disease 89:631-639.
Gent , D. H., Lang, J. M., and Schwartz, H. F., 2005. Epiphytic survival of Xanthomonas axonopodis pv. allii and X . axonopodis pv. phaseoli on onion and dry bean. Plant Disease 98: 558-564.
Gent , D. H., Lang, J. M, Bartolo, M. E., and Schwartz, H. F. 2005. Inoculum sources of Xanthomonas axonopodis pv. allii in Colorado . Plant Disease 89:507-514.
Gent, D. H., Al-Saadi, A., Gabriel, D. W., Louws, F. J., Ishimaru, C. A., and Schwartz, H. F. 2005. Pathogenic and genetic relatedness among Xanthomonas axonopodis pv. allii and other pathovars of X . axonopodis . Phytopathology 95:918-925.
Gent , D. H., Schwartz, H. F., and Khosla, R. 2004. Distribution and incidence of Iris yellow spot virus in Colorado and its relation to onion plant population and yield. Plant Disease 88: 446-452.
Gent, D. H., Schwartz, H. F., Ishimaru, C. A., Louws, F. J., Cramer, R. A., and Lawrence, C. B. 2004. Polyphasic characterization Xanthomonas strains from onion. Phytopathology 94:184-195.
Gent , D. H., Schwartz, H. F., and Nissen, S. J. 2003. Effect of commercial adjuvants on vegetable crop fungicide coverage, absorption, and efficacy. Plant Disease 87:591-597.
Schwartz, H. F., Otto, K. J., and Gent , D. H. 2003. Relation of temperature and rainfall to development of Xanthomonas and Pantoea leaf blights of onion in Colorado . Plant Disease 87:11-14.
Gent , D. H. and Schwartz, H. F. 2003. Validation of potato early blight disease forecast models for Colorado using various sources of meteorological data. Plant Disease 87:78-84.
Schwartz, H. F., Brown, W. M., Blunt, T., and Gent , D. H. 2002. Iris yellow spot virus on onion in Colorado . Plant Disease 85:838.
