Temporal and spatial factors affecting germination of macroconidia of Sporidesmium sclerotivorum

Abstract

20703-2350 Abstract: Macroconidia of Sporidesmium sclerotivo? rum are stimulated to germinate by sclerotia of Scler? otinia minor. Substantial differences in germination rate were demonstrated among ten isolates of Spori? desmium sclerotivorum. The rate of germination was usually related to the maximum percent germina? tion, i.e. competence, of the strain; strains with a greater proportion of competent macroconidia ger? minated more rapidly. Parameters for stimulating ma? croconidia of a rapidly germinating strain of Spori? desmium sclerotivorum were investigated in vitro and in soil. A single sclerotium stimulated maximum ger? mination of macroconidia in less than one week. Treatment with additional sclerotia increased the de? centimeter in soil. At that distance in soil, but not at 2 centimeters, the expanding germ tube of the my- coparasite was able to reach a sclerotium and infect it. These studies suggest that the mechanism of ger? mination plays a role in the survival of this fastidious mycoparasite, which is useful for biological control of Sclerotinia species.