Seasonal development and life cycle—Phytophthora

All Phytophthora species require high soil moisture, but temperature requirements vary. Phytophthora cinnamomi, a species prevalent in California, spreads, infects plants, and develops rapidly during warm, moist conditions. P. cactorum requires cool, moist weather. Phytophthora fungi can survive in the soil for many years and enter plants through the crown or roots. Depending on the species of fungus, Phytophthora may affect only small feeder roots or rootlets, major roots, or all roots and the crown.