The influence of soil biotic factors on the ecology of two Trichoderma biocontrol agents

Abstract: The sensitivity of Trichoderma atroviride and T. hamatum biocontrol agents to a rangeof common soil fungi and actinomycetes was tested in co-culture on agar medium, sterile andnon-sterile soil. Six test fungi (Alternaria alternata, Aspergillus niger, Chaetomium globosum,Metarhizium anisopliae, Paecilomyces lilacinus, and Daldinia eschscholzii) inhibited bothTrichoderma species to varying degrees. In general, T. atroviride was more sensitive thanT. hamatum and inhibition observed in agar culture and sterile soil was greater than that observedin non-sterile soil. Our results suggest that Trichoderma populations would be maintained in thesoil when exposed to field levels of these test microbes and that biocontrol activity would not becompromised.