Factors Affecting Conidial Exudation and Survival, and Ascospore Germination ofLeucostoma cincta

Conidia of Leucostoma cincta from sweet cherry were exuded from pycnidia at 2 to 28°C with an optimum exudation at 20°C. Free water was needed for exudation at incubation periods of 6 to 24 h at 20°C. Conidia were exuded at 100% relative humidity during 48 and 72 h of incubation. A large proportion of conidia in dried cirrhi survived summer conditions in the field. Ascospores germinated at 10 to 28°C with an optimum at 28°C during incubation times of 12 to 24 h. Conidia germinated at 15 to 28°C during an incubation period of 24 h. Maximum germination of conidia occurred at 28°C during 24 h of incubation. Conidia germinated at 5 to 20°C when incubation periods were extended to 48 and 72 h. Inoculations of sweet cherry trees with ascospores of L. cincta resulted in infection and development of stem cankers.