Weakening Effect on Propagules of<i>Fusarium</i>by Sublethal Heating

Abstract

Sublethal heating of conidia and chlamydospores of Fusarium oxysporum f.sp. niveum at 38-42 C caused 0-33% reduction in propagule viability and resulted in a weakening effect in the surviving propagules. This weakening effect was expressed as a delay in germination, in reduction in growth of conidial and chlamydospore germ tubes, and in enhanced decline of the population density of viable conidia in soil. Viability of conidia that were heat-treated or exposed to solarized soil declined faster than unheated conidia in a soil suspension culture