 Over winter in the soil, oospores survive and wait for spring.In warmer conditions when it gets to about 47-53 degrees F the oospores will germinate and produce an appressorium or form a short germ tube.The mycelium grows intracellularly and haustoria penetrate through the host cells when the temperature is around 60 degrees F. After about 1–2 weeks when the temperature is between 60-64 degrees F, conidiophores (the asexual stage) will form out of the plant stomata bearing conidia.