Phytophthora Aerial Blight -- Phytophthora parasitica
Host: Chamaedorea spp., croton, Pilea spp., shefflera, vinca, african violet, spathiphyllum
Symptoms: Phytophthora aerial blight causes lesions on the leaf that are brown to black in color, irregularly shaped and necrotic. From these lesions, sporangia develop in pools of water on the leaf surface. Blight of stems and small shoots will accompany blight of leaves.
Conditions Favoring Disease: This disease is favored by humid conditions, overhead irrigation and rainfall, and very warm weather. Under less favorable conditions, root rot occurs.
How Pathogen Survives/Disperses: The fungus can survive for extended periods of time in infected, fallen leaves. It may also survive in the soil as oospores.
Photo and write up provided by Syngenta Professional Products