Botrytis Blight

Botrytis blight is most visible during bloom and near harvest, when you'll notice flowers taking on a watery, brown appearance before dying. Gray mold covers affected tissues during wet conditions, giving the disease its characteristic name. On blueberries, the disease can move from infected flowers back into the fruiting wood, causing branch dieback. Green fruit can rot if rain continues into late spring and early summer. On ornamental plants like peonies and butterfly bush, you'll see blighted flower clusters turning brown and withering. This fungus overwinters on dead twigs and plant debris, making garden sanitation critical in Western Washington's moist climate.

Botrytis cinerea survives on dead organic matter and infected tissue as dormant mycelium and sclerotia. In spring, when temperatures rise and moisture increases, spores spread by wind and splashing water. Infection risk is highest during bloom and again at harvest. Susceptibility is greatest on cultivars that retain floral structures over long periods. The key to control is preventive: prune annually to remove infected and winter-damaged twigs, opening the canopy for air movement. Space plants for good air circulation and quick drying of foliage. Use drip irrigation or overhead watering only in early morning, allowing foliage to dry quickly. Avoid late-season fertilization that stimulates winter-tender new growth. After harvest, move fruit to cold storage immediately to slow disease development.