Tar spot changing the fungicide game

MARKLE, Ind. — Tar spot, a relative newcomer to the Corn Belt’s disease lineup, is changing the way that growers and agronomists look at fungicides on corn.

One of the biggest changes that growers may see is adopting a two-pass fungicide application system to meet the disease head on.

“Year in and year out, that R1 timing on corn has been the prime spot for application for maximizing returns. Tar spot probably is going to change some of that,” said Chad Threewits, Syngenta Agronomy service representative for Northern Indiana.

Even with fungicides like Trivapro® from Syngenta, growers will want the extended benefits of long-lasting residual control of corn diseases to address early season disease issues and to keep diseases like tar spot and Southern rust, which can cause standability and stalk quality issues, at bay for as long as possible.

“We are never going to have 100% control of all diseases. But, keeping those diseases under control and in check through grain fill is key. If we can get through grain fill and as close to black layer as possible, if that plant doesn’t die and it hasn’t completely cannibalized the stalk, we can maximize yield potential. A lot of times, that’s all we can do when facing diseases like tar spot and Southern rust. They are so aggressive that we are trying to push that collapse as late in the season as possible,” Threewits said.

In years like 2021, the two-pass fungicide application with Trivapro offers growers protection when diseases make an early appearance.

“This year, the tar spot came in early; the Southern rust came in early. Even a little prior to that tassel time frame, we saw benefits with fungicide applications because we had such a good environment for disease. Gray leaf spot and Northern corn leaf blight started much earlier, even this year, that even a little earlier fungicide treatment showed good results,” Threewits said.

With the trademarked SOLATENOL® technology, Trivapro provides preventive and curative disease control.

With higher commodity prices and more growers to protect yield with fungicides like Trivapro, Threewits said growers need to make sure that they can get the fungicide applied in time to obtain the benefits of the residual control Trivapro offers.

“I see that as our next challenge, going into 2022, being able to physically cover all the acres in Indiana that want a fungicide application,” he said.

“For 2022, that is one of my concerns, can we make the timely applications if we have heavy disease pressure? Can we get the acres covered to hit that next level of growers who are adopting fungicides?”

Product performance assumes disease presence.

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This column was contributed by Indiana AgriNews for Syngenta.