Effects of nikkomycin and echinocandin on differentiated and undifferentiated mycelia of Botrytis cinerea and Mucor rouxii

As undifferentiated mycelia of Botrytis cinerea aged, the leading hyphae extended faster and became wider, to form mature differentiated mycelia. There was a direct correlation between hyphal extension rate and the square of hyphal diameter. Equivalent hyphae of Mucor rouxii also extended faster and became wider as colonies aged, but did not show this direct correlation. The wider, faster growing leading hyphae of differentiated mycelia of both fungi were much more susceptible to bursting by treatment with nikkomycin than were hyphae in young colonies. Those of B. cinerea were also much more susceptible to bursting by echinocandin B. Regrowth of surviving hyphae after treatment with echinocandin B was characterized by multiple branching of both young and old hyphae. Echinocandin B had no effect on M. rouxii. Spore germination of B. cinerea was inhibited by nikkomycin, and germ-tubes became swollen. Spore germination of B. cinerea was inhibited by nikkomycin, and germ-tubes became swollen. Spore germination of M. rouxii was more sensitive than that of B. cinerea, with spores becoming swollen and producing multiple germ-tubes. Echinocandin B caused spores of B. cinerea to swell abnormally and produce multiple germ-tubes.