2000 Volume 66 Issue 1 Pages 5-11
Environmental factors influencing release and dispersal of conidiospores of Mycovellosiella nattrassii Deighton, causal fungus of leaf mold of eggplant, were studied in the laboratory and greenhouse. In the laboratory, the average number of conidiospores released from lesions on artificially inoculated leaves was 468/cm2/24 hour under 50% of relative humidity, however, under 100% of relative humidity spores released few. At 20-25°C in the dark under 50% relative humidity, more conidiospores were released than at other temperatures and light exposures. But few conidiospores were released under 100% relative humidity, in spite of optimal temperature and light conditions. In field tests, the number of conidiospores released from three lesions on naturally infected leaves increased during the day with low humidity following days with successively high humidity. The dispersal of conidiospores also increased on fine days immediately after a change from high to low humidity. On the other hand, few spores were dispersed at night or on rainy or cloudy days. These results seem to indicate that relative humidity was the main factor influencing release and dispersal of conidiospores from lesions on of eggplant leaves.