Japanese Beetles Are On The Move In Corn And Soybeans

Boots in the Field Report with Ken Ferrie

© Crop-Tech Consulting

In the past week, Ken Ferrie says he has seen a lot of “forward motion” with corn crops in Illinois because of the available GDUs (growing degree units).

As the corn has been rapidly elongating the stalks are now subject to high winds that have accompanied the heat, resulting in green snap. The question Ferrie is now fielding from farmers is, “Will those stalks make ears?”

“If the stalks haven’t completely snapped, they might catch some pollen and make a small ear. But really, the outlook for these plants is pretty bleak,” says Ferrie, Farm Journal Field Agronomist and owner of CropTech, Inc.

If you’ve had high wind in the past week, Ferrie says don’t delay in sending up a drone to get an idea of the damage in your fields.

Look for Japanese beetles in both corn and soybeans, and be prepared to take action. Ferrie says his concern is getting the corn crop pollinated before Japanese beetles do any significant silk clipping. The issue is when the silks are clipped before or during pollination the ears may be only partially pollinated. Silk clipping after pollination does not usually affect yield potential.

In soybeans, the plants often are able to compensate for damage the beetles cause. However, Ferrie says because most soybean crops contain smaller than normal plants due to late planting this season, defoliation is of a greater concern than usual.

Seed companies recommend that insecticide applications in soybeans should be considered if:

1. 30% defoliation occurs prior to bloom, or
2. 20% defoliation occurs during flowering or pod fill, and
3. Beetles are present and actively feeding.

Along with managing pest issues, Ferrie says farmers need to be managing landlords’ expectations for this season. “I’m expecting more weed problems because of this year’s weather conditions, and we might be taking weeds out with the combine,” he says. “Make sure you keep landlords abreast of how the growing season is going and what kinds of agronomic issues your fields are experiencing.”

To learn more about agronomic issues Ferrie is seeing this year, listen to his Boots In The Field podcast here: