A new method for producing mycelium-free conidial suspensions from cultures of Microdochium nivale

A technique to improve the sporulation of Microdochium nivale in culture and to produce mycelium-free conidial suspensions was evaluated using cellophane-covered potato dextrose agar (PDA). Time to sporulation was significantly shorter on the cellophane-covered PDA (P<0.001), yields of conidia were higher (P<0.01) and conidial suspensions were produced virtually free of the mycelial fragments present in suspensions from PDA only. The conidial inoculum produced on cellophane had lower pathogenicity to wheat cv. Equinox in a detached leaf assay, showing significantly longer incubation periods (P<0.05) and latent periods (P<0.01), than conidia produced on PDA alone. However, the apparent decline in pathogenicity of conidial suspensions produced on cellophane compared to PDA alone was small.