LONDON MILLS, Ill. — Every growing season brings both new and the usual yield-robbing suspects to corn and soybean fields.

Lance Tarochione, Asgrow and DeKalb technical agronomist, said black cutworm and stinkbugs are among the insects that could bug farmers this season.

“We’re already seeing some signs that it could be a bad black cutworm year and late planting favors the black cutworm because the plants are smaller when the larvae are bigger. That means they can do more damage and cut more plant,” Tarochione said.

“Black cutworm moth flights have been higher than normal. Anytime you have higher than normal black cutworm moth flight, you’ve got green fields. Most of these fields have not had a burndown on them yet. We had a cold winter and a cold spring, so it hasn’t gotten as green as it a lot of years by May 1.

“But if the next couple weeks are warm and wet instead of cold and wet, you’re going to have some of these fields that haven’t been burned down start looking like a pasture, and that’s where he cutworm moths like to lay their eggs. You can get some really heavy black cutworm damage.”

There were many reports of brown marmorated stinkbugs last year that can over-winter as adults and feast on young corn.

“They’ll eat about anything. They have a probing mouth part, they’re kind of a piercing sucking insect and they’ll use their proboscis to pierce the host plant to feed. If they get too close to the growing point when they tunnel into that young corn seedling, it basically turns that plant into a weed. The plant may never die but it grows abnormally, it doesn’t really set an ear, it doesn’t make a tassel and turns it into a weed,” Tarochione said.

“We’re seeing more and more of that kind of damage. A lot of people misdiagnose as just a weird looking plant, but in many cases, it’s stink bug feeding that caused that plant to look that way.”

Tarochione said scouting of early season insect pests is a challenge.

“From an integrated pest management standpoint, it doesn’t really sound good whenever we tell guys that they better throw some insecticide in with that herbicide application just in case. There are a lot of people who like to be aggressive managers that do like to do that. It’s an expense — not a big expense, but it is an expense — and then we’re putting insecticide out on some acres that probably didn’t have to have it,” Tarochione said.

“You’ve got to stay on top of that stuff. If you’re going to scout and treat like a good IPM would tell you to do, then you’ve got to be scouting and you need to scout frequently. You can’t just drive by from the road and say that looks all right.”

Disease Pressure

Most fungal diseases favor high moisture conditions. Some fungi-, soil-based diseases like it cool and wet, and others prefer warm and wet.

“It’s pretty early for foliar fungal disease. For example, gray leaf spot likes it hot and wet, but it needs to be hot and wet in June for gray leaf spot to be bad not April and May,” Tarochione said.

“It’s a little hard to say how some of the foliar diseases will be impacted by weather because the weather that impacts them isn’t here yet.

“You couldn’t ask for a better environment for sudden death syndrome in soybeans right now. Every field of soybeans planted in Illinois is probably under some level of SDS pressure right now. It depends on the genetics, the seed treatment and the environment the rest of the summer how bad it gets, but the potential is certainly going to be there based on the weather pattern.”

Tom C. Doran can be reached at 815-780-7894 or Follow him on Twitter at: @AgNews_Doran.


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