Diagnose: Rose Powdery Mildew

1. Powdery mildew when white-gray colonies spread across living rose surfaces
2. Inspect both surfaces of young rose leaves, then follow the coating onto red shoots, sepals, and unopened buds. Powdery mildew looks like irregular floury patches or a thin felted mat, and infected young tissue may curl, twist, or stay small as it expands. Check whether the white material returns or expands on living tissue after a gentle rub. Angular purple lesions with sparse growth beneath the leaf, dark spots with yellow halos, gray decay on petals, fixed water marks, or fine mite webbing require a different diagnosis.

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