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VIEW ARTICLE
The Effect of Inoculum Levels on Field Evaluations of Potatoes for Verticillium Wilt Resistance. J. A. Frank, Research Plant Pathologist, U. S. Department of Agriculture, Agricultrual Research Service, Orono, Maine 04473; R. E. Webb, Research Plant Pathologist, USDA, ARS, Beltsville, Maryland 20705; and D. R. Wilson, Horticulturist, USDA, ARS, Presque Isle, Maine 04769.
Phytopathology 65:225-228. Inoculum levels of Verticillium albo-atrum can be adjusted to develop different populations of the pathogen in the soil throughout the growing season. Severity of Verticillium wilt on potatoes is related to the inoculum density during tuberization, and to the environment. The wilt resistance of the 12 potato cultivars used in this test could be modified by alteration of the inoculum concentration. Even the highest level of wilt resistance available could be broken by high populations of the pathogen. Actual populations of the pathogen in the soil of the growing region should be compared to those developed in test plots to insure meaningful ratings of disease reaction. Additional key words: population density, clones. |