Corn growers across Ohio know how disruptive vomitoxin in corn can be at harvest. Contaminated grain may face discounts, marketing restrictions, rejected loads, storage concerns, and added uncertainty when deciding what to do with affected corn.
Also known as DON, vomitoxin is not a problem you can solve with one management practice. Weather around silking, hybrid susceptibility, disease development, harvest timing, grain handling, and storage can all influence the risk.
That is why the Ohio Corn Checkoff (OCMP) continues investing in research at The Ohio State University to better understand DON and help farmers make informed decisions before, during, and after harvest.
The information below can help you understand the risk, recognize potential problems, and plan your next steps. For recommendations specific to your fields, work with your certified crop adviser or agronomist.
What Is Vomitoxin in Corn?
DON vomitoxin, short for deoxynivalenol, is a mycotoxin that can be produced when corn is infected by Fusarium graminearum. The same fungus causes Gibberella ear rot, one of the ear diseases associated with DON contamination in corn grain. Ohio State notes that infection occurs primarily around pollination when silks are wet.
So, what is vomitoxin in practical terms? It is not the mold itself. It is a toxin the fungus can produce after infecting the developing grain.
This distinction matters because a field does not necessarily need to show severe visible mold for DON to be present. Ohio State reports that the fungus can produce vomitoxin after entering the ear even when later conditions do not produce obvious external ear-rot symptoms.
What Causes High Vomitoxin Levels in Corn?
Weather around silking plays an important role in vomitoxin corn risk.
The fungus primarily infects ears during pollination through wet silks. Warm, humid, or wet conditions around this stage can create favorable conditions for infection and disease development. Insect feeding and ear injury later in the season may provide additional opportunities for infection, although Ohio State identifies silking as the primary infection period.
As your crop approaches and moves through silking, consider these practical steps:
- Monitor local weather conditions.
- Scout during flowering and ear development.
- Know the susceptibility of the hybrid you planted.
- Watch for insect or weather-related ear damage.
- Discuss fungicide timing with your agronomist where disease risk warrants treatment.
- Consider harvest timing when disease pressure is present.
No single factor guarantees DON contamination, which is why field scouting and local conditions remain important.
How to Recognize Gibberella Ear Rot
Gibberella ear rot is caused by Fusarium graminearum, the same fungus associated with DON contamination. Visible symptoms may include white, pink, or reddish mold on the ear, but visual symptoms alone cannot confirm the DON level in the grain.
For more information, review Ohio State guidance on Gibberella ear rot and DON.
Testing Corn for Vomitoxin
If you suspect DON contamination, corn testing can help guide decisions about marketing, feeding, storage, and handling. Because DON may not be distributed evenly throughout a field, bin, or load, representative sampling is important.
Follow the sampling requirements of your grain buyer or testing facility, and confirm acceptance requirements before delivery.
How Vomitoxin Can Affect Grain Marketing
DON contamination can affect where grain can be sold and what a buyer is willing to pay for it.
Depending on the level detected and the intended use of the grain, a buyer may:
- apply a discount;
- restrict how the grain can be blended or used;
- redirect the grain to another market; or
- reject a load that does not meet its specifications.
There is no single DON level that applies to every buyer or livestock feed use. FDA advisory levels vary by animal species and by how much contaminated grain is included in the total ration. Review the FDA advisory levels for DON and confirm current acceptance requirements with your buyer before delivery.
Vomitoxin Research for Ohio Corn Growers
Checkoff-supported research continues to help us understand the disease from several angles: the pathogen, the corn plant, the environment, and the decisions farmers can make throughout the season.
Current areas of research include:
- Hybrid response: Evaluating how hybrids perform under different disease and weather conditions.
- Fungicide studies: Examining application timing, product performance, and disease control.
- Harvest strategies: Identifying practices that may help reduce the impact of contaminated grain.
- Post-harvest management: Studying drying, cleaning, storage, and other mitigation approaches.
- Collaboration with Ohio State: Turning field research into practical information Ohio farmers can use.
Through the Ohio Corn Checkoff, we continue supporting research designed to reduce risk, protect grain quality, and help growers respond more effectively when DON becomes a problem.
How Can Corn Growers Reduce Vomitoxin Risk?
You cannot eliminate every risk factor, but decisions made during the growing season, harvest, and storage can help limit additional problems.
Harvest, Clean, and Store Affected Corn Carefully
When disease pressure is present, harvest timing and grain handling deserve extra attention.
Consider the following:
- Harvest affected fields promptly when conditions allow to reduce the time damaged ears remain in the field.
- Adjust combine and cleaning practices to remove as much lightweight, damaged material and fines as practical.
- Dry grain promptly and store it in clean, cool bins.
- Monitor stored grain for temperature changes, insects, mold, and other signs of deterioration.
Drying and cooling will not remove DON that is already present. These practices help limit further fungal growth and protect grain quality after harvest.
Grain cleaning may also reduce the amount of contaminated material in a lot by removing damaged kernels and fines, but results can vary with the grain and equipment used.
Time Fungicide Applications Carefully
Fungicide can be part of a disease-management program, but timing matters.
Because Fusarium graminearum primarily infects ears through wet silks during pollination, the critical management window occurs around silking. Ohio State identifies this stage as the main infection period for DON-associated Gibberella ear rot.
If you are considering treatment:
- Evaluate weather, hybrid susceptibility, and disease risk.
- Discuss product choice and application timing with your agronomist.
- Make decisions for individual fields rather than assuming every field carries the same risk.
Fungicide is one management tool not a guarantee that DON will be eliminated.
Vomitoxin and Livestock Feed
DON deserves particular attention when contaminated corn may enter livestock rations. FDA advisory levels vary by animal species and by the proportion of contaminated grain in the total diet.
If you plan to feed affected grain, test it first and work with a veterinarian, nutritionist, or feed specialist to determine whether and how it can be used safely.
Frequently Asked Questions About Vomitoxin in Corn
What causes high vomitoxin in corn?
DON risk is strongly associated with infection by Fusarium graminearum, particularly when conditions around pollination and silking favor infection. Weather, hybrid susceptibility, and crop injury can all contribute to field-level risk.
Is DON the same as vomitoxin?
Yes. DON is short for deoxynivalenol, the mycotoxin commonly called vomitoxin.
Can drying corn remove vomitoxin?
No. Drying grain does not remove DON that has already formed. Proper drying and storage are still important because they help maintain grain condition and limit additional deterioration.
Can corn with vomitoxin still be used for livestock feed?
Potentially, depending on the DON concentration, animal species, and amount included in the total ration. Because FDA advisory levels differ by species, test affected grain and get appropriate feed or veterinary guidance before use.
Together, We're Making Progress
Dealing with vomitoxin in corn can be challenging, but every season gives us more information about how the disease develops and how growers can respond.
Through your Ohio Corn Checkoff investment and our continued collaboration with Ohio State researchers, we’re working to turn that knowledge into practical strategies that help you reduce risk, protect grain quality, and make more informed decisions when DON shows up in your crop.
Better disease knowledge, scouting, timely management, corn testing, and sound harvest and storage practices can help you protect crop quality and your bottom line.
