Biological control of sporidesmin-producing strains of Pithomyces chartarum by biocompetitive exclusion.

Abstract

The feasibility of using atoxigenic strains of Pithomyces chartarum for the biological control of toxigenic strains of P. chartarum was examined. Pasture, treated with atoxigenic strains of P. chartarum, contained up to 80% less sporidesmin than found in untreated pasture. Maximum sporidesmin levels of 26 ng g-1 grass in treated pasture and 113 ng g-1 grass in untreated pasture (means of 24 and four plots, respectively) were recorded 14 weeks after treatment, when spore numbers had reached a maximum of 80,000 spores g-1 grass in the untreated plots and 50,000 spores g-1 grass in the treated plots. This trial demonstrated that sporidesmin-producing spores of P. chartarum could be successfully reduced in pasture by the addition of atoxigenic strains, thereby reducing the risk of facial eczema in livestock.