Plan on at Least One Fungicide Application for Corn and Beans


WESTFIELD, Indiana (June 23, 2022) – “These last few years, we’ve shifted from a scout-to-spray mindset to a recognition that we need to be planning on a fungicide application for corn and soybeans to achieve our high yield goals,” says Robby Meeker, an LG Seeds agronomist in East Central Illinois.

Meeker says over the last few years, more farmers have become believers in at least one fungicide application to protect crops against disease threats. “Most of the farmers in my area now incorporate fungicide applications into their budget plans,” he says.

Farmers need to plan their fungicide applications now if they are experiencing a humid start to the season, like he’s seeing in Illinois, Meeker emphasizes.

Why the mindset shift?
“Our approach five years ago was scout to spray. But farmers’ recent experience using fungicides convinced many to plan on using fungicide for both corn and soybeans, rather than waiting for scouting results,” Meeker says. Some of that mindset change is also driven by a better understanding of a plant’s potential.

Meeker recalls his father and grandfather thinking the corn crop was done once it had made an ear. “Now, we want corn to stay green and healthy even through the final maturity growth stage at R6 to pack as much starch as we can into that kernel, increasing its size and weight to build yield,” he says.

“Farmers see they can realize more of a seed’s yield potential thanks to the added protection of fungicide,” Meeker says, adding he has often witnessed treated corn outperform untreated corn.

The protection a fungicide offers also allows soybean plants to flourish.1 That impact is especially pronounced when it’s combined with an insecticide, Meeker says.

More fungicides with longer residuals hit the market
An influx in new products has also helped shift attitudes on fungicides. “Since 2020, we’ve seen an upgrade with companies bringing out new modes of action and longer-lasting residuals that have helped with consistency of response,” Meeker says.

When choosing a fungicide, Meeker advises looking for products with longer residuals. “A lot of the newer products have 10 to 14 days longer residual action than products we had five or 10 years ago,” he says.

Plan for one application and scout from there
Farmers should plan on making one fungicide application to corn at tasseling and then scout from there, keeping in mind your fungicide’s 30- or 45-day residual. An optimal time for that first application is “when you start to see a tint of brown to the silks,” Meeker elaborates.

But he adds, “if we keep up this humidity, an earlier application right as tassels are coming out but before we’re pollinating may be beneficial.”

During a high-pressure year, Meeker says farmers should “definitely consider a second application post-pollination,” urging them to be proactive in their response to any disease re-emergence.

For soybeans, Meeker recommends a similar approach. “I would plan on one application at the R3/R4 growth stage but scout to see if an additional application is needed.” If it’s a higher stress year for the Corn Belt or if there are a lot of hurricanes that blow frogeye leaf spot up from the South, Meeker says a second application will likely be needed.

For either crop, farmers should make sure to read the labels and ensure the application window fits the fungicide label.

Scout fields now
“Scouting starts today,” Meeker says. The big four corn diseases farmers should be watching for in the central and eastern Corn Belt include southern corn rustnorthern corn leaf blighttar spot, and gray leaf spot.

For soybeans, Meeker says frogeye leaf spot and Septoria brown spot are common problems.

He recommends following your local extension service for disease tracking and reaching out to your local LG Seeds agronomist for help getting the most out of your crops.