VIEW ARTICLE

Ecology and Epidemiology

Microsclerotial Germination of Cylindrocladium crotalariae in the Rhizospheres of Susceptible and Resistant Peanut Plants. D. T. Krigsvold, Department of Plant Pathology and Physiology, Virginia Polytechnic Institute and State University, Blacksburg 24061, Present address of senior author: Tela Railroad Co., Research Division, United Fruit Co., LaLima, Honduras; G. J. Griffin(2), and M. G. Hale(3). (2)(3)Department of Plant Pathology and Physiology, Virginia Polytechnic Institute and State University, Blacksburg 24061. Phytopathology 72:859-864. Accepted for publication 22 October 1981. Copyright 1982 The American Phytopathological Society. DOI: 10.1094/Phyto-72-859.

Microsclerotia of Cylindrocladium crotalariae were tested in artificially infested, unsterile soil for germination in the inner 1-mm of the rhizospheres of plants of peanut cultivars resistant (Argentine) and susceptible (VA-72-R) to the pathogen. Germination was significantly higher in the rhizosphere of the susceptible versus the resistant cultivar. Microsclerotium germination in response to crude root exudates from axenically grown peanut plants also was greater in soil for the susceptible than for the resistant cultivar. Higher levels of carbon were required for Argentine root exudate than for VA-72-R root exudate to support similar levels of microsclerotial germination in soil. For each cultivar, percentage of germination was related directly to carbon levels in the root exudate. Each of the 14 peanut root exudate components (sugars, amino acids, and organic acids) tested were stimulatory to microsclerotium germination in soil.