Managing Black Spot Fungus on Holly Bushes

Diagnosis

Leaf loss on multiple hollies with small black spots on leaf undersides indicates black spot fungus, a common foliar disease. The "bald" spot from last year has expanded.

Integrated Treatment

Apply a fungicide labeled for black spot on hollies (e.g., chlorothalonil, mancozeb). Simultaneously, fertilize with a 20-10-10 or similar ratio to stimulate new growth. Prune out severely affected branches. Improve air circulation by thinning dense growth.

Cultural Practices

Water at the base, not overhead. Mulch to reduce splash dispersal. Clean up fallen leaves in autumn to reduce overwintering inoculum.