Corn Ear Rots

Diplodia

Infection is attributed to a period of wet weather following silking. The fungus begins at the base of the ear and appears as a whitish mold later consuming the entire ear and turning gray or brown. Husks adhere tightly to the ear. Spores of the fungus reside in the previous crop's residue. Crop rotation, tolerant hybrids and clean tillage will help to reduce the incidence of this disease in corn. Dry corn to 15% moisture or lower to limit spread of the disease in storage.

Fusarium

Symptoms vary greatly, but generally individual or groups of infected kernels are found randomly throughout the ear. Infection typically occurs at the tip of the ear where injury from insects or hail may have caused ear damage. The mycotoxin fumonisin is produced by this disease. Grain should be tested for mycotoxins if fed to livestock. Crop rotation, tolerant hybrids and clean tillage help control this disease. Dry corn to 15% moisture or lower to limit spread of the disease in storage, but best to feed it or sell it rather than storing.

Gibberella

Wet weather within the first couple of weeks after silking favors the development of this ear rot. A pink to red mold starts at the tip end of the ear and progresses down the ear. Husks may adhere tightly to the ear. Infected corn or wheat residue are sources of inoculum for this disease. Hybrids with tight husks appear to be more prone for infection than hybrids with loose husks. Crop rotation, namely soybeans, and clean tillage are ways to manage this disease.

Penicillium

Fungus begins at the ear tip as a greenish-blue mold. Infection occurs primarily as a result of insect or mechanical damage to the ear tip. If infected grain is stored at high moisture levels (> 18%), the fungus may invade the kernel and discolor the embryo resulting in a condition called "blue eye". Plant hybrids that are resistant to feeding from corn borer and ear worm.

Have a good weekend

Dan Childs, Agronomist

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