Check Cornfields for Stalk Rots

Farmers should scout cornfields now for anthracnose and other stalk rots.

University of Missouri Extension corn specialist Greg Luce says stalk rots, including anthracnose, charcoal, diplodia and fusarium, can be found to some extent in cornfields across much of the state.

Scout fields before corn matures, 40-60 days after pollination, Luce says. Check 10 sections of a field for stalk rot. Anthracnose stalk rot may not appear in the entire field.

Anthracnose shows up late in the growing season. Infected plants begin dying prematurely. Black, shiny streaks or spots appear mostly on the lower portion of the stalk. In some cases, the entire stalk blackens.

Affected plants fall when pushed. Stalks yield easily when squeezed between the thumb and forefinger. Split stalks appear discolored and rotted during the top dieback phase, also known as ghosting.

Drought and wet conditions can make plants more vulnerable to the disease. Water shortages, extended periods of cloudy weather, hail, insect infestation, low potassium-nitrogen rates, leaf diseases and other stresses during August and September increase chances of stalk rot.

“Heat this year put extra stress on the plants,” Luce says. “High nighttime temperatures are particularly stressful to corn and increase respiration and reduce defense against stalk rots.”

Yield losses can be up to 40 percent, Luce says, but losses are typically much less than that.

To avoid anthracnose stalk rot, choose resistant hybrids with good stalk strength and lodging traits. Also, rotating crops reduces stress. Luce says to use sound fertility and pest management methods.

Reduce residue in fields. Stalk rot fungi and bacteria are part of the complex of microorganisms that decompose dead plant material in the soil. They survive from one growing season to the next in soil, in infested corn residue or on seeds.

Luce does not recommend foliar fungicides particularly for anthracnose, but he says they may help indirectly by reducing stress on the plant from foliar diseases such as gray leaf spot.

Pinch stalks or push on them to check for rot and weak stalks. If the field shows more than 10 percent or more of stalk rot, harvest early to avoid lodging and yield loss.

“A big wind could easily take down the weakest fields,” Luce says. “Early harvest of fields with signs of stalk rot cuts losses. Even if you don’t suspect a problem, it is good to check fields to see which fields to harvest first and avoid surprises.”

For more information, the MU Integrated Pest and Crop Management article “Corn Stalk Rots” is available at

Source: University of Missouri

Recent News

The 2020 Outlook for U.S. Agriculture From USDA’s Chief Economist

Speaking on Thursday at USDA’s Agricultural Outlook Forum in Arlington, Virginia, USDA Chief Economist Robert C. Johansson provided a broad outlook for U.S. agriculture.  Today’s update provides an overview of key aspects of Dr. Johansson’s presentation. In his speech Thursday (transcript / slides), Dr. Johansson noted that, “Despite mixed signals heading into 2020, there has been important progress on the trade policy […]

Corn Prices-Farmer Holding and the Coronavirus

Old crop corn basis and futures spreads continue to signal a smaller crop scenario than the price levels in the futures market suggest.  Futures price levels reflect the uncertainty associated with the coronavirus and the potential weaker growth its continuation promises.  Producer grain holding remains the popular explanation for a strong basis and small futures […]

Highlights from USDA Trade and Commodity Outlook Reports

Following this month’s release of the USDA’s Long-Term Projections, on Thursday, the Department released its quarterly Outlook for U.S. Agricultural Trade.  This update provided an overview of agricultural trade based on the 2020 fiscal year, which began in October, months before the U.S. and China signed the Phase-One trade agreement.  Recall that Phase One farm purchase commitments are based […]

Your browser is out-of-date!

Update your browser to view this website correctly. Update my browser now