How to Manage Pests

UC Pest Management Guidelines

SYMPTOMS

Fusarium ear rot results in white to salmon-pink discoloration of individual kernels or groups of kernels scattered over the ear. A white to pinkish weft of mycelia covers the kernels, especially on the tip of the ear. In severe infections the ears may be completely consumed by the fungus, leaving lightweight husks cemented to the kernels by mycelia.

COMMENTS ON THE DISEASE

Fungus growth is often associated with damage of the kernels caused by the feeding activity of insects. Although feeding damage by the corn earworm is readily apparent, it is the unseen damage caused by thrips that is indirectly responsible for most of the losses to ear rot in California. Thrips gain access to the kernels through the silk channel opening soon after pollination. The fungus is found on all corn tissue, but causes few problems unless tissue is damaged. Ear rot is most common in the Delta and in the Sacramento Valley.

MANAGEMENT

Use hybrids that have been thoroughly tested for ear rot resistance. Resistance is found in those hybrids with long husks that tightly enclose the silk channel opening of the ears. Husks that prevent or delay entrance of insects are responsible, in part, for resistance to ear rot. Early plantings usually escape serious injury. There are no registered fungicides for this disease.

PUBLICATION

UC IPM Pest Management Guidelines: Corn
UC ANR Publication 3443
Diseases
R. M. Davis, Plant Pathology, UC Davis

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