By Connor Lynch
There’s no silver bullet to preventing vomitoxin, also known as DON, in corn, according to OMAFRA’s field crop pathologist, Albert Tenuta. The keys are resistance and fungicide: No hybrid is immune to DON, but some are better than others.
Senior agronomist with Agris Co-op, Dale Cowan, recommends planting multiple hybrids to spread out risk. In particular, avoid the high-risk hybrids like DEKALB 5505, PRIDE 7373, or PIONEER PO825. They were found to be some of the most susceptible to DON infection.
According to Tenuta, the two most effective fungicides are Proline and Caramba. Spraying at silking is the recommendation: The majority of last year’s DON infections were through the silk channel.
Basic best practices apply as well. Uniform emergence and growth help limit the impact of DON, and any stress on your plants can make them more susceptible to it.
Western Ontario’s corn crop was devastated by DON — a toxic mould byproduct — that whacked many farmers right in the pocketbook. Discounts at elevators typically kicked in at 3 parts per million (ppm) of the toxin, and cutoffs were often at 8 ppm. Many farms took price cuts on their corn, and some had sky-high DON levels, as much as 40 ppm.
Grain Farmers of Ontario estimated farmers lost as much as $200 million to the infection. They estimated over a quarter of Ontario’s entire corn crop, about 600,000 acres, had levels of DON high enough that the corn was discounted.
