It may not feel like it should be here yet, but the longest day of the year is fast approaching (June 21) and the coinciding short night triggers indeterminate soybeans to flower.

Why does that matter? Because, said John Swanson, Federated agronomist at the Ogilvie location, “shortly after this we must start scouting for flowers” to be able to effectively fight white mold.

Fungicides should be applied earlier than most other plant health products, which typically go on at R3, according to Swanson. “Getting the proper timing when applying fungicides is extremely critical,” he said, emphasizing that “white mold fungicide applications must be put on at R1 or beginning bloom, which is one open flower at any node on the main stem.”

Scouting at this point is essential. “As soon as we see a flower we need to be spraying,” he said. White mold spores enter the soybean plant through the senescing flowers; the plant needs to be protected before the flowers begin senescing.

“One of the [fungicides] we have had success with here at Federated is Aproach®,” said Swanson. With applications of Aproach at 9 oz./ac. at R1, “we have seen a decrease in incidence [of white mold] as well as nice yield increases,” he said.

If/when environmental conditions are optimal for white mold infections, Federated recommends applying a second application of Aproach at 9 oz./ac. 14 days after the first treatment. Swanson, said, “Aproach is not going to eliminate white mold 100%, but it will decrease incidence and improve yields,” and, as everyone knows, yield matters.

Talk to your Federated Agronomist soon with any questions about white mold and preventive treatments.