By Andi Anderson
Deoxynivalenol (DON), commonly known as vomitoxin, has become an increasing concern for corn growers in recent years. The toxin is linked to Gibberella ear rot (GER), a disease caused by the fungus Fusarium graminearum. What was once considered an occasional problem has become a recurring challenge in some corn-growing regions.
Researchers at The Ohio State University, including Dr. Pierce Paul and the Cereal Pathology Lab team, have developed weather-based forecasting models to help growers assess the risk of DON contamination. The models use temperature and relative humidity data to determine whether conditions favor grain contamination levels of at least 1 part per million (ppm).
Farmers can access these forecasts through the Crop Protection Network’s Crop Risk Tool. The tool allows users to evaluate risk levels based on local weather conditions and the pollination timing of specific fields. The information can help producers decide whether fungicide applications are needed for disease management.
The risk tool classifies conditions as low, moderate, or high risk. Low-risk periods generally indicate limited chances of DON contamination, while moderate and high-risk conditions increase the likelihood of grain contamination, especially in susceptible hybrids and fields with a history of corn or wheat production.
The fungus primarily infects corn during pollination when silks are wet and receptive. For this reason, fungicide timing is critical. Research has shown that fungicides provide the greatest benefit when applied during the early to mid-silking stage while silks remain wet. Applications made after silks turn brown are significantly less effective in reducing DON levels.
Several fungicide products are available for suppressing GER and reducing DON contamination. However, experts emphasize that fungicides alone are not enough. Successful management requires an integrated approach that combines weather monitoring, resistant hybrids, proper crop rotation, and suitable tillage practices.
Hybrid resistance remains one of the most effective tools for reducing toxin levels. Studies have shown that hybrids with partial resistance generally produce lower DON levels than susceptible hybrids, even when fungicides are used. Fields planted with highly susceptible hybrids, especially those grown no-till after corn, face a greater risk of contamination under favorable disease conditions.
Researchers also recommend identifying fields that pollinate during high-risk periods and prioritizing them for early harvest. Delayed harvest can increase the amount of DON produced in grain, particularly during wet weather conditions.
Experts stress that weather alone does not determine disease development. The presence of fungal spores, hybrid susceptibility, and environmental conditions must all align for significant DON contamination to occur. As a result, growers should use forecasting models as one part of a broader management strategy.
By combining forecasting tools, resistant hybrids, timely fungicide applications, and effective production practices, corn growers can better manage vomitoxin risks and protect grain quality throughout the growing season.
Photo Credit: gettyimages-dszc
Categories: Ohio, Crops