Widespread distribution. Asia, North America, Oceania. On frangipani, and Madagascan periwinkle. Spots yellowish-orange on the underside of leaves, bursting to produce powdery spore masses. Brown patches above. Usually, minor disease, although leaves fall earlier than normal. Unsightly.
Spread as spores by wind; leaf wetness to infect.
Cultural control: cuttings from disease-free trees; collect fallen leaves and burn; tolerant varieties.
Chemical control: nurseries: chlorothalonil, copper, or mancozeb (protectants); or oxycarboxin or tridimefon (eradicants).