Vegetative growth and conidium production by Monilinia oxycocci in vitro

The effects of various natural agar media, light, and temperature on myceli um growth of and conidium production by Monilinia oxycocci were examined in the laboratory under controlled conditions. Vegetative growth and sporulat ion were affected differentially by these factors. Optimum vegetative growt h and formation of stromata occurred on potato dextrose agar at 20-24 C in the dark. The minimum and maximum temperatures for mycelium growth were 4 a nd 32 C, respectively. Production of conidia was best on V8 juice agar. The greatest numbers of conidia were produced at 16 C, but abundant conidium p roduction was most consistent at 20 C. The influence of light on sporulatio n was inconsistent among trials and differed among media and isolates. Howe ver, on V8 juice agar at 20 C, production of conidia was most abundant in t he dark. In general, considerable variability occurred with M. oxycocci thr oughout the study-among replicates of individual isolates, among isolates w ithin a trial, and among trials with the same isolates. The highly variable nature of M. oxycocci in vitro appears to be an inherent characteristic of this plant pathogenic fungus.