Holly Tree Defoliation: Powdery Mildew

Mature holly with milky-white leaves dropping rapidly = powdery mildew. Flexible leaves = not dead yet, but heavily infected.

Control

1. Fungicide spray (both sides): myclobutanil, propiconazole, chlorothalonil, or sulfur.
2. Repeat per label (7–14 days).
3. Rake/destroy fallen leaves—major spore source.
4. Thin canopy for air flow (winter).

VT Link

Virginia Tech fact sheet in original has detailed mildew control.

Large trees hard to spray fully—consider hiring arborist with spray equipment. But mildew rarely kills mature hollies.