VIEW ARTICLE

Disease Control and Pest Management

Relation of Verticillium dahliae in Soil and Potato Tissue, Irrigation Method, and N-Fertility to Verticillium Wilt of Potato. J. R. Davis, Professor, Department of Plant, Soil and Entomological Sciences, University of Idaho Research and Extension Center, Aberdeen, 83210; D. O. Everson, professor, Department of Mathematics and Applied Statistics, University of Idaho, Moscow 83843. Phytopathology 76:730-736. Accepted for publication 5 February 1986. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/Phyto-76-730.

Investigations of several potato-growing areas in Idaho showed inconsistent relationships between populations of Verticillium dahliae in soil and wilt severity. This lack of consistency was associated with cultural management practices. Increases in severity of Verticillium wilt were more highly correlated with furrow irrigation than with sprinkler irrigation. Irrigation method and N, K, and P applications accounted for as much as 71% of the field variability related to colonization of V. dahliae in potato stem tissue. Increased availability of nitrogen suppressed the incidence of Verticillium wilt on the cultivar Russet Burbank but had no effect on severity with the cultivar Norgold Russet. Wilt severity was also correlated positively with populations of soilborne Pratylenchus spp. Studies over several years provided no evidence to suggest direct associations for either increased wilt or reduced yield as a result of infection by Colletotrichum atramentarium.