Large numbers of conidia are disseminated from sclerotia in the spring when there are wet periods of 24 hours and temperature is above 36 °F (2 °C). The conidia infect the young leaves, shoots, and berries of the grape vine. Conidia will germinate, causing primary inoculum under the following circumstances: presence of free water in 12 hours and adequate temperature (36-90 °F (2-32 °C)). In fact, primary inoculum of Grape Anthracnose is possible even before bud break. The infection rate will escalate with increases in temperature. Development of disease symptom is also temperature-dependent: within 13 days at 36 °F, or within 4 days at 90 °F.