How to Manage Pests

Pests in Gardens and Landscapes

Seasonal development and life cycle—Botrytis rot

The fungus that causes gray mold, Botrytis cinerea, survives in decaying plant material in or on the soil and as sclerotia. Botrytis infects primarily through germination of its airborne spores. An injury or dead or dying tissue must be present for the fungus to invade. On lettuce, aging wrapper leaves or older leaves at the bottom of plants are usually first infected. Wrapper leaves often provide entry sites for crown rot. Head rot may develop on sites damaged by aphids or downy mildew or other diseases.

Infection in lettuce crownInfection in lettuce crown


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