Effects of inoculation concentration, photoperiod and temperature on growth, conidiation and conidial germination of Bionectria ochroleuca

The short-term stock of Bionectria ochroleuca ochroleuca at 4°C was activated, sub-cultured, and grown at 25°C on PDA medium for 10 days to obtain a working culture. To determine the effect of temperature on fungal growth, the plates were incubated at 15, 20, 25, and 30°C under continuous darkness or an 8 h light/16 h dark regime for 10 days. To investigate the effect of photoperiod on fungal growth and reproduction, fungal cultures were incubated at 25°C with 0, 8, 16, and 24 h light exposure per day for 10 days. The cultures were exposed to full light induced by fluorescent lamps with 800–1200 lx. Mycelial growth was measured as the mean of two randomly selected orthogonal diameters of the colony on day 10 with a ruler. The colonies were in the shape of near-perfect circles, with differences between two diameters less than 1%. The conidia were then washed out using a spreader with 10 ml ddH2O. A spore suspension was transferred to sample tubes with a pipette and quantified using a hem...