Watch no-till corn for fungal disease

COLUMBUS – Corn growers who use no-till or minimal tillage practices face potential disease problems this growing season.

Wet weather conditions and residue left in reduced tillage fields has growers and Ohio State University researchers monitoring cornfields for anthracnose, a fungal disease.

The disease, which caused a widespread yield loss last year, is off to the same start this year, said Pat Lipps, an Ohio State University Extension plant pathologist with the Ohio Agricultural Research and Development Center.

“The same situation as last year has developed, and growers with the problem last year definitely know the potential loss,” Lipps said.

Disease promoted. Most of last year’s problem areas are struggling with the fungus again because it survives over winter in residue.

This year’s spring rainfall promoted the disease, splashing the fungal spores onto the lower leaves of young corn plants, Lipps said. From there, infected plants commonly develop leaf blight and eventually stalk rot.

Brown, oval lesions begin appearing on the lowest leaves of infected plants in June, Lipps said. Damp conditions later in the season foster the disease as it climbs up the plant leaf by leaf, and spores from leaf lesions cause stalk infections.

Plants with stalk infections die prematurely and lodge before harvest, causing yield losses, Lipps said.

“Control options for anthracnose are implemented before the crop is planted, so nothing can be done now,” he said. “All growers can do is scout their fields to check for the stalk rot phase.”

Watch for it. Growers should watch for plants with black speckles or stripes on corn stalks. These plants, which easily break, should be harvested early to minimize yield loss from lodging, Lipps said.

To minimize future problems, growers can plant resistant hybrids, implement tillage practices to destroy last year’s crop residue and develop a crop rotation plan, he said. The disease is usually more serious under reduced tillage systems and in fields of continuous corn.

“Everything depends on the weather,” Lipps said. “If it stays wet, I predict considerable lodging problems. All we can do is let growers know if the disease progresses later in the season.”

For more information about anthracnose, log onto www.oardc.ohio-state.edu/ohiofieldcropdisease.