Dennis A. Johnson
Plant Pathologist, Extension Plant Pathologist, and Professor
Research Specialty and Interests
Epidemiology and management of diseases of irrigated crops, and ecology of plant pathogens on natural vegetation. Areas of published research articles include disease resistance, disease forecasting, spatial patterns of diseased plants, disease etiology, and disease management. Host plants of which research articles have been published include the following: potato, mint, asparagus, hop, sweet cherry, onion, barley, wheat, corn, oat, and water lilies.
Professional Experience
- WSU Assistant, Associate, and Professor and Plant Pathologist 1980-present.
- Texas A&M University, Texas Agri. Exp. Sta., Assistant Plant Pathologist 1978 and 1979.
- Plant disease and agricultural advisor in Java, Indonesia January, 1989.
Awards and Professional Activities
- Friend of the Mint Industry - 1994
- American Phytopathological Society
- Canadian Phytopathological Society
- The Potato Association of America
Selected Publications
Johnson, D. A., Alldredge, J. R., Hamm, P. B., and Frazier, B.E. 2003. Aerial photography used for spatial pattern analysis of late blight infection in irrigated potato circles. Phytopathology 93:805-812.
Johnson, D. A., Inglis, D. A., and Miller, J. S. 2004. Control of potato tuber rots caused by oomycetes with foliar applications of phosphorous acid. Plant Dis. 88:1153-1159.
Porter, L. D., and Johnson, D. A. 2004. Survival of Phytophthora infestans in surface water. Phytopathology 94:380-387.
Porter, L. D., Inglis, D. A., and Johnson, D. A. 2004. identification and characterization of resistance to Phytophthora infestans in leaves, stems, flowers, and tubers of potato clones in the pacific Northwest. Plant Dis. 88:965-972.
Porter, L. D., Dasgupta, N., and Johnson, D.A. 2005. Effects of tuber depth and soil moisture on infection of potato tubers in soil by Phytophthora infestans. Plant Dis. 89:146-152.
Atallah, Z. K., Larget, B., Chen, X., and Johnson, D. A. 2004. High genetic diversity, phenotypic uniformity, and evidence of outcrossing in Sclerotinia sclerotiorum in the Columbia Basin of Washington State. Phytopathology 94:737-742.
Atallah, Z. K., and Johnson, D. A. 2004. Development of Sclerotinia stem rot in potato fields in south-central Washington. Plant Dis. 88:419-423.
Johnson, D. A., Alldredge, J. R., and Vakoch, D. L. 1996. Potato late blight forecasting models for the semiarid environment of southcentral Washington. Phytopathology 86:480-484.
Johnson, D. A. 1995. Races of Puccinia menthae in the Pacific Northwest and interaction of latent period of mints infected with rust races. Plant Dis. 79:20-24.
Johnson, D. A. 1994. Effect of foliar infection caused by Colletotrichum coccodes on yield of Russet Burbank potato. Plant Dis. 78:1075-1078.
Johnson, D. A., Alldredge, J. R., and Allen J. R. 1994. Weather and downy mildew epidemics of hop in Washington State. Phytopathology 84:524-527.
Miller, J.S., and Johnson, D.A. 2000. Competitive fitness of Phytophthora infestans isolates under semiarid field conditions. Phytopathology 90:220-227.
Johnson, D.A., Cummings, T.F., and Geary, B. 2000. Postinfection activity of selected late blight fungicides. Plant Dis. 84:1116-1120.
Johnson, D.A., Alldredge, J.R., and Hamm, P.B. 1998. Expansion of potato late blight forecasting models for the Columbia Basin of Washington and Oregon. Plant Dis. 82:642-645.
Johnson
Hall 317A (office) &
Vogel Plant BioScience 127(lab)
Tel.: (509)335-3753
Fax: (509)335-9581
E-mail: dajohn@wsu.edu
Teaching:
Epidemiology and Management of Plant Diseases - PlP 551. Principles and practical implications of plant disease epidemiology, disease management, and pathogen ecology. Examples of diseases caused by fungi, prokaryotes, viruses, and nematodes of crops grown in the Pacific Northwest and of international importance are used in discussions of the above topics.
Cooperative Extension Responsibilities:
Dieases of potato and mint in central Washington.s
Professional Activities:
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