WOOSTER, Ohio – Severe stalk rot from anthracnose, a corn residue-borne disease, is creating the potential for stalk lodging throughout Ohio cornfields.
Ohio State University plant pathologist Pat Lipps said growers should scout fields for stalk lodging potential and should prioritize which fields to harvest first based upon their evaluations.
Lodging losses. “Lodging is one of the more important aspects of stalk rot. A grower can lose more yield to lodging than to the actual effect of the disease on grain production,” said Lipps.
“Anthracnose is out there. It’s extremely critical that growers be aware of the stalk quality issues they are facing.”
How to scout. Lipps recommends that growers scout their fields for stalk rot by pinching the lower nodes of the stalks and evaluating how soft the stalks are.
“The best scouting procedure is to squeeze 20 plants in a row, go to another part of the field and squeeze another 20 plants. Do this four or five times throughout the field,” he said.
Lipps said that anywhere between 10 percent and 50 percent of corn plants evaluated in southern Ohio fields have a stalk rot problem. “It’s looks like they are ready to lodge at any given moment,” said Lipps. Stalk rot problems are beginning to show up in the northern and western parts of the state, as well.
Conditions. Stalk rot is one phase of the fungal disease anthracnose. The leaf blight phase develops early in the season and is brought on by wet weather conditions.
Lipps said that because of wet weather early in the growing season, anthracnose is much more common than usual.
“Stalk rot seems to be more widespread throughout the state. Growers in the southern part of Ohio are seeing stalk rot now. Growers in the north will start seeing it soon,” said Lipps.
Stalk rot causes black discoloration or streaks on the stalk surface, and the stalks become very soft due to fungal colonization of the internal stalk structure. Stalk rot leads to stalk lodging, the final stage of the disease where the plants are so weak they fall down.
“The worst thing that can happen to a farmer at this point is to have a field lodge,” said Lipps. “When 50 percent of the field goes down, we’re talking a 35 percent loss in yield and the money spent to produce the crop is lost to the ears lying in the field.”
Lipps said stalk rot will become more prevalent throughout Ohio cornfields as the plants continue to mature, but emphasizes that stalk lodging is highly dependent on field situations. Some corn hybrids have resistance to anthracnose or can limit the amount of stalk lodging.
