How to Manage Pests

Pests in Gardens and Landscapes

Bacterial soft rots of onions and garlic—Erwinia, Pseudomonas, and Enterobacter spp.

Bacterial soft rots are primarily a problem on onions, but not garlic. They are characterized by softening and water soaking of one or more of the inner fleshy scales of the bulb. Affected tissue is yellow initially, turning brown as the disease progresses lengthwise in the bulb. The neck of infected bulbs may be soft when pressed. A foul-smelling odor is also associated with these disorders.


Free water is essential for entry and spread of the bacteria. Wounds and senescent leaves are the means by which bacteria gain entrance into the bulb. Avoid overhead irrigation once onions start to bulb (bulbing occurs about the time the bulb is twice the diameter of the neck). Harvest only after onion tops are well matured. Provide for quick drying following topping, especially if temperatures are high.

Rotting of garlic bulbs
Rotting of garlic bulbs

Rotting of inner fleshy tissue
Rotting of inner fleshy tissue

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