Crown rot threat in cornfields this fall

PITTSFIELD, Ill. — AgriGold agronomist Brett Leahr is concerned crown rot will be widespread in the Corn Belt this fall, especially in his territory that stretches from northern Missouri to central Illinois.

The area includes multiple soil types, environments, rain patterns and planting dates.

Leahr shared a few key points in a recent press release.

1. “Ghost plants” signal crown rot risk — So-called ghost plants, characterized by dying cornstalks with a brownish-pink tint, have been appearing in fields since August.

These are often the first signs of Fusarium-related crown rot, a growing concern in the Corn Belt, especially after this year’s wet spring.

Leahr warned that infected plants could reduce ear size by up to 27%, leading to yield loss.

2. Compounded by wet conditions and nitrogen deficiency — The wet spring left many cornfields vulnerable to crown rot, particularly in areas with poor drainage and soil compaction.

“In recent years, we haven’t had harsh winters with freeze-and-thaw cycles that break up the soil,” Leahr said. “Consequently, layers of compaction have been building.”

Nitrogen leaching, caused by heavy rain, makes plants more susceptible to diseases like tar spot, further weakening crops.

Early infections from Fusarium are often hidden, but can severely impact plant health during the grain fill period.

“If you come down with the flu (crown rot) and you get hit in the nose (tar spot), it handicaps your body’s ability to fight back,” Leahr said.

3. Early harvest and field management are key — Farmers are encouraged to scout for ghost plants.

“If you see a lot of ghosted plants in the field, consider making plans to harvest it early,” Leahr said.

If crown rot is detected in more than 5% of the field, early harvest is advised to prevent stalk breakage and crop loss.

Leahr also recommended ensuring adequate nitrogen levels, improving drainage and diversifying hybrids to protect against future outbreaks.