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Biological
Control With a Plant Pathogenic Bacterium,
Pseudomonas corrugata
Wesley Chun
Pseudomonas corrugata is bacterium that causes pith necrosis disease only in tomatoes and a few cultivars of pepper. This bacterium is also a strong antagonist of certain phytopathogenic bacteria and a broad spectrum of phytopathogenic fungi. Since its host range is limited, we can take advantage of its root colonizing ability and antimicrobial properties, and safely apply the bacterium as a biological control agent on non-host plants. To demonstrate this ability, we studied the application of P. corrugata on a bacterial pathogen (Clavibacter michiganensis subsp. sepedonicus = ring rot disease) and a fungal pathogen (Helminthosporium solani= silver scurf disease) of potatoes in greenhouse and field tests. We found that P. corrugata treatments significantly reduced populations of the ring rot bacterium in potato stems. When a dry talc formulation of P. corrugata was applied to cut seed tubers, a 17% yield increase in Russet Norkota was observed. When P. corrugata was applied to H. solani infected seed tubers, a 27 to 39% reduction in disease incidence was observed in greenhouse tests. In field tests, 83-90% of the tubers examined had little to no silver scurf disease while 64% of the control treatments were infected. Mutagenesis of P. corrugata has resulted in the identification of a superior strain that is non-pathogenic in tomatoes and has increased production antimicrobial activity. Thus, P. corrugata is a useful biological control agent that is genetically suitable for the development new strains that would be useful as a bioprotectant.
Wesley Chun
Dept. of Plant, Soil and Entomological Sciences
University of Idaho
330 Agricultural Sciences Bldg.
Moscow, ID 83844-2339
Tel: (208) 885-5708
Wchun@Uidaho.edu
The work to create this publication was sponsored by the Western Sustainable Agriculture Research and Education (Western SARE) program. Western SARE is an effort of the U.S. Department of Agriculture. Since 1988 through federal fiscal 2000, the U.S. Congress has allocated more than $114.6 million to the federal SARE effort; Western SARE has received $26 million. The Western region includes Alaska, Arizona, California, Colorado, Hawaii, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, Wyoming and the Island Protectorates of American Samoa, Guam, Micronesia and the Northern Mariana Islands.