Seasonal variation in the inoculum potentials of spermosphere fungi

Abstract

Turnip seed baits were used to measure the seasonal variation in inoculum potentials of spermosphere fungi. Soil moisture appeared to be the key factor in the marked variation which was observed. Fusarium and Pythium spp. dominated spermospheres in soil which had been at field capacity for more than a few days, Actinomyces spp. dominated spermosphores for a short period when hot dry soil was brought to field capacity by rain. Drying of soil in summer decreased the inoculum potentials of Pythium spp. and Saprolegniaceae considerably, and Fusarium spp. slightly, and increased inoculum potentials of Mucor, Aspergillus, Penicillium, and Trichoderma spp.