Abstract
The present paper dealt with the mycelial growth, sporulation, conidium germination and appressorium formation of Botrytis cinerea in relation to the incubation temperature and spore age. The optimum temperature for mycelial growth on PSA medium was in the range of 24-28°C, and the maximum and minimum temperature seemed to be at 0° and 35°C, respectively (Fig. 1).
The sporulation was observed on PSA medium at 24°C and on sponge matrices which had been incubated in a moist chamber at 24°C after shake-culturing for 4 days in PS medium (2% sucrose) with sponge matrices. On the sponge matrices, conidia were produced synchronously about 24 hours after transferring to moist chamber (Fig. 3). Sporulation on PSA medium, however, was initiated 3 days after inoculation and reached the maximum from 4th to 6th day after the inoculation (Fig. 2).
Young conidia, in general, germinated well at 20°C comparing with old conidia. Eighty seven per cent of germination was secured of the conidia produced synchronously on the sponge matrices. However, rapid reduction in germination of conidia occurred with the elapse of time, and after 3 days incubation germination fell down to less than 50 per cent. After 6 days incubation almost no germination of conidia took place in water (Fig. 3). Most of the conidia germinated, however, were capable of forming appressoria at the tip of the germ tube.
