Benomyl-tolerant microfungi associated with mycorrhizae of black spruce

Abstract

The population of microfungi associated with mycorrhizal root tips of Picea mariana was sampled to determine which species were able to grow on isolation medium amended with the selective fungicide benomyl. Benomyl significantly favoured the isolation of soil Zygomycetes, including members of the genera Mortierella and Micromucor, but inhibited the growth of most soil fungi of ascomycetous affinities. Since some of the inhibited taxa, e.g., Trichoderma spp., are potential inhibitors of mycorrhiza formation in vivo, these results may explain instances where the application of benomyl has been shown to increase mycorrhiza formation in the field.