Sporulation of Cercospora capsici Heald et Wolf on sweet pepper leaves occurred under continuous light or dark condition in laboratory tests. The optimum temperature for sporulation was 17-18°C in the light, but 25°C in the dark. The data shows that sporulation of C. capsici interacts between light and temperature. In a plastic house many conidiospores were released during on the daytime or fine day preceded by a couple of rainy days, but few conidia were trapped at night.The number of spores released increased sharply around 10 a.m., when the plastic house was opened, and reached a maximum around 12 p.m. Spore dispersal rapidly decreased immediately after closing of plastic house in the evening. Release and dispersal of many spores brought about by air currents, a rise in temperature and a drop in relative humidity in a plastic house.