Risk of Corn Grain Contamination with Vomitoxin in Ohio in 2024: A July 15th Projection

Based on weather data collected from CFAES weather stations located in Ashtabula (LAT: 41.8846, LON: -80.6978), Franklin (LAT: 40.0112, LON: -83.0442), Noble (LAT: 39.7478, LON: -81.5167), Jackson (LAT:  39.0519, LON: -82.6367), Sandusky (LAT: 41.3503, LON: -83.1219), Wood (Latitude:  41.2847, Longitude: -83.8444), Pike (LAT: 39.0681, LON: -83.0144), Clark (LAT: 39.8633, LON: -83.6721), and Wayne (LAT: 40.7787, LON: -81.9308) Counties, OH, grain developing in corn fields in close proximity to the stations that reach the R1 growth stage between July 13 and July 19 are at high risk of being contaminated with at least 1 ppm DON. However, since the temperature and RH data used to make these predictions may vary within a few miles of the nearest CFAES station or with changes in elevation, the specific prediction for your individual field may be different. In addition, our models were not developed to predict whether DON will be 2, 5, 8, or 10 ppm, they only predict whether DON will be ≥ 1 ppm. This prediction could be interpreted to mean that conditions are favorable for infection and initial DON production, but whether or not contamination will be considerable higher that 1% will depend on other factors.     

It is important to remember that weather conditions are only one side of the disease triangle, and that all three sides of the triangle are needed for disease development, and in this case, for DON contamination to occur. Consequently, the actual level of DON contamination will vary from field to field, depending on the susceptibility of the hybrid planted, tillage, and crop rotation, as well as weather conditions. Under favorable weather conditions, a highly susceptible hybrid planted no-till into corn stubble will likely be contaminated with DON well above 1 ppm compared to a tilled field of a moderately resistant hybrid planted after beans.

Effective management of DON requires the combination of multiple strategies. Use these predictions along with information about hybrid susceptibility and production practices to help guide your DON management decisions. Model predictions can be used to help you determine if a fungicide for DON management would be beneficial. Of the many fungicides available for corn disease management, two are considered to be the most consistently effective at suppressing GER and DON. These two products are Proline and Miravis Neo. They have shown the best results when applied at the R1 growth stage when silks are still wet (early- to mid-R1). The fungicide must penetrate the canopy and reach the corn silks when they are still wet to be effective. Applications made after silks are dry and brown are considerably less effective at reducing DON.

Hybrid resistance is critical even with a fungicide application in achieving low DON levels at harvest. A hybrid with partial resistance will have lower DON at harvest than a susceptible hybrid when both have received a fungicide application for DON management. Extended harvest periods allow more time for DON production, particularly if harvest is delayed by wet conditions. An additional tool is to scout fields that pollinate during high-risk times for GER and plan to harvest those fields early.

These models are the first step towards the development of a prediction tool that would be available to growers to run on a daily basis to assess DON risk at their field location during pollination. As more data are collected, models will be developed to predict the risk of higher levels of contamination (2 ppm, 5 ppm, etc etc). The current model development has been generously supported by the Corn Marketing Board through your corn check-off.

More information on the development of the Corn grain Vomitoxin risk model and management of DON in corn can be found in this corn newsletter article: https://agcrops.osu.edu/newsletter/corn-newsletter/2024-22/risk-corn-grain-contamination-vomitoxin-ohio-2024-july-8

Estimates of the risk of DON contamination of corn grain are provided at no cost within the state of Ohio. The model developers, The Ohio State University, and funding agencies cannot guarantee prediction accuracy. Users should always consult extension educators and state and field specialist when making disease and mycotoxin management decisions.