How to Manage Pests

Pests in Gardens and Landscapes

Seasonal development and life cycle—Blue mold rot

Many species of Penicillium can cause blue mold. The fungi are common on plant debris and senescent plant tissue. Invasion of onion bulbs and garlic is usually through wounds, bruises, or uncured neck tissue. Once inside the bulb, the fungus grows through the fleshy scales, eventually sporulating profusely on the surface of lesions and wounds. Optimum conditions include moderate temperatures and high relative humidity.

Invasion of garlic bulbs causes stunting
Invasion of garlic bulbs causes stunting


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