Corn School: Fungicide timing and tank-mix strategies to protect yield and quality

There is tremendous yield potential in Ontario corn fields right now. With recent rainfalls, subsoil moisture has been replenished and the crop has jumped in the last few days. Great looking acres and strong corn prices both weigh into the decision to apply fungicides.

In this Corn School episode, Bernard Tobin is joined by BASF agronomist Ken Currah to discuss fungicide strategies to protect grain yield and quality throughout the summer.

“This is about protecting our investment and shooting up yields… going into the last half of the growing season,” says Currah.

A fungicide application on corn should happen at the tassel and silk timing, depending on what your intentions are, says Currah. Using a Group 11 product that manages and suppress leaf diseases, such as northern corn leaf blight, eye spot, grey leaf spot, rust, or even tar spot, should be applied from tassel emergence to brown silk, at the end of the pollination window.

If you’re adding a Group 3 product to the mix to control vomitoxins and manage DON, Currah says the application window is at green silk timing, when most of the plants in the field have an inch or more of green silk protruding from the ear, up to brown silk timing. (Story continues below video)

“The overlying factor here is managing your crop, and not the weather,” says Currah. Weather conditions will play into other factors affecting the corn crop like other diseases or insects. Heat spells in southern Ontario bring with them southwestern and southerly air flows, which can bring insects or disease up from the U.S. — western bean cutworm and northern corn leaf blight.

Currah says a preventative approach is best when considering which fungicides and insecticides to use. “We want to watch the news from the corn belt, we want to watch what happens in southwestern Ontario as the crop advances and matures and disease or insect pressure might advance as well,” says Currah, adding to follow the scouting and integrated pest management process for insecticides.

Finally, Currah says that pre-mixed products or safe tank mixes of different groups of fungicides are absolutely imperative to keeping efficacy of these products and avoiding resistance management. Currah adds that scouting for insects before spraying them in a reactive way is important for stewardship, too.

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