Soybean Anthracnose

Encyclopedia Article

Photo of Anthracnose of soybenAnthracnose is a fungal disease that sometimes occurs in late summer in Iowa. Typically this disease does not cause severe symptoms or yield loss. Development of anthracnose is favored during periods of moderate temperatures and high humidity or wet weather.

Anthracnose is caused by the fungus Colletotrichum dematium var. truncatum and several related species. The fungi survive between seasons in infested crop residue and seed.

Symptoms of anthracnose are reddish veins, rolled leaves, and dark blotches on stems, pods and leaf petioles. Severe infection can lead to premature defoliation. The irregularly shaped brown blotches caused by anthracnose may resemble pod and stem blight. Often, anthracnose and pod and stem blight occur together on the same plants late in the season.

Management of Anthracnose

The disease is seedborne, so do not use seed from infected plants. Seeds from plants infected by anthracnose may or may not show discoloration.

The fungus can also survive from year to year in crop debris. Rotate crops and till areas where anthracnose occurred to bury inoculum and prevent a build-up of the pathogen.


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