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United States Department of Agriculture

Agricultural Research Service

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Kenneth Deahl
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Dr. Ken Deahl

Research Plant Pathologist


Phone: (301) 504-5131



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Staff: Frances Perez

Biographical Information

        Ph.D. Plant Pathology and Agricultural Microbiology, West Virginia University
        M.S. Plant Pathology, West Virginia University
        B.S. Biology and Animal Science, Fairmont State University

Research Interests

  • my program has the goal of developing improved management strategies for vegetable diseases by increasing our understanding of pathogen biology and plant-microbe interactions
  • my current and future efforts include basic research on the worldwide migrations of Phytophthora infestans
  • developing a modern understanding of the population genetics of P. infestans
  • investigate the epidemiological impact of exotic strains of P. infestans in the USA

My research program has focused on oomycete pathogens. Oomycetes are somewhat obscure, fungus-like organisms that capture public attention when they destroy crops or invade new hosts. Oomycetes are filamentous microorganisms that resemble fungi in their morphology and lifestyle. Many oomycetes are parasites of plants or animals and cause disease, whereas others are saprophytic and free-living. Oomycetes and fungi are similar in form but have evolved independently. These parasitic organisms that rely on the hosts to complete their life cycles face unstable and rapidly changing selective pressures, as their own reproduction affects the health and success of their host. Late blight disease of potatoes and tomatoes is caused by the plant pathogen Phytophthora infestans. The completion of the P. infestans genome sequence represents a milestone because of the importance of this organism to history and the study of plant disease. As every student of plant pathology knows, P. infestans caused the Irish potato famine of the 1840s. The rapid spread of the disease after it was accidentally introduced to Europe from the Americas resulted in utter destruction of the potato crop. It remains the most spectacular example of a catastrophic disease epidemic. Anton de Bary described the life cycle of P. infestans some 140 years ago, making it among the first pathogenic microorganisms to be well characterized. Research studies on these organisms are conducted in many locations, as P. infestans and other oomycetes continue to pose problems as plant pathogens and invasive organisms around the globe. However, the application of molecular and DNA sequencing analyses has altered our view of oomycetes and provided new insight into the evolution of these organisms and how they have excelled as plant pathogens.

Publications (click on publication tab at left)


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Last Modified: 8/11/2016
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