Prevalence of Verticillium Wilt of Tomato and Virulence of Verticillium dahliae Race 1 and Race 2 Isolates in Western North Carolina. C. G. Bender, Former Graduate Student, Department of Plant Pathology, North Carolina State University, Raleigh 27607. P. B. Shoemaker, Professor, Department of Plant Pathology, North Carolina State University, Raleigh 27607. Plant Dis. 68:305-309. Accepted for publication 3 October 1983. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-305.

Verticillium wilt was confirmed in 56% of 108 tomato fields surveyed (56.5% of 65.6 ha) in western North Carolina in 1976. Estimated disease incidence in the surveyed region was 9.2%. Eighty-nine of 96 Verticillium dahliae isolates recovered from susceptible cultivars in the survey were race 1; seven were race 2. Six race 2 isolates came from fields not previously cropped with race 1-resistant cultivars. In field tests, mean yields were reduced in susceptible cultivars Manapal and Walter and race 1-resistant cultivars Flora-Dade and Monte Carlo, respectively, by as much as 39.9, 47.1, 3.5, and 6.5% by race 1 isolates and 10.3, 31.2, 19.3, and 22.8% by race 2 isolates.