How to Manage Pests

Pests in Gardens and Landscapes

Seasonal development and life cycle—Botrytis fruit rot

Botrytis fruit rot occurs under cool, wet conditions. Physical damage to the plant increases disease incidence, especially during the rainy season. The pathogen overwinters as sclerotia on infected canes and sometimes as mycelium in infected tissues. Spores from overwintering structures and dead leaves and mummified berries are the main sources of primary inoculum. Spores are dispersed by wind, rain, and overhead irrigation. Flowers are not susceptible to infection until they have opened. Infections generally remain dormant until fruit is nearly ripe, or after harvest. Infections can reoccur throughout the season by sporulation of the fungus on unpicked, overripe fruit left on the vine.

Sclerotia overwinter on canes

Sclerotia overwinter on canes


Statewide IPM Program, Agriculture and Natural Resources, University of California
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