BLOOMINGTON, Ill. — “Wait until next year” is a phrase often attributed to unsuccessful sports teams, but it shouldn’t be a farmer’s pest management approach after corn reaches maturity.

Now is a good time for root digs to get a better handle on what happened and what could be changed next year.

“It doesn’t hurt to dig up a few plants and just see what kind of root system we have this year,” said Tom Kelley, Syngenta’s central Illinois agronomy service representative.

“The corn plant in central Illinois did not have to put on a lot of roots this summer because it was sitting in a greenhouse essentially. It had plenty of moisture, plenty of nutrients, so we don’t have a large root system to begin with, so it doesn’t take much rootworm feeding for that root system to be compromised.”

The Iowa rootworm rating scale is recommended to determine the extent of larval damage on crown roots.

“That’s the zero to three rating and it’s fairly easy to do and if you need help, you can get a hold of your seed adviser or your Syngenta agronomist and we can show you how to scout fields,” Kelley said.

“Now is a perfect time. It’s not the easiest job, but for August our temperatures are not normally what they are in the mid-90s. It’s not a bad job to help make plans for the future.”

If a field has heavy insect pressure after the corn reaches maturity, it’s too late to apply insecticide, but not to use that information to tweak next season’s pest management.

“I call those revenge sprays,” Kelley said of applying insecticides after brown silk. “You’re basically taking revenge against the insect, and you cannot put a big enough dent in that population to make a difference for next year.

“A lot of the beetles you’re seeing have probably already laid their eggs or a getting ready to lay their eggs, so they’ve already set the stage for next year.”

There are numerous tools available to manage pests, ranging from seed treatment and insecticides to traits.

“Syngenta is introducing a new trait next year called Agrisure Duracade, which is a new mode of action that we’re very excited about,” Kelley said.

Duracade trait expresses a unique protein — eCry3.1Ab — for control of corn rootworm.

“It kind of gets us out of that same arena that all of the other corn rootworm traits are operating in. It gives us something new with higher efficacy to bring to the Midwest farmer,” Kelley said. “It breaks that cycle of resistance with a new mode of action.”

He also offered pest management recommendations for this year’s corn crop that was planted late and has yet to reach full maturity.

“At Syngenta, one product that we consider kind of a base product is Warrior insecticide. That not only controls corn rootworm adults, but it also controls earworm, European corn borer, western bean cutworm and a lot of other insects that it does control,” he said.

“If you have a really bad infestation, a lot of people are also tank-mixing other insecticides with Warrior to give it a quick knockdown if they’re in that critical of a situation to get pollination. We have such a small window on pollination we have to knockdown all those bugs that we can to get good pollination.”

In terms of determining at what point in the plant growth stage it no longer is beneficial to apply a fungicide, Kelley said, brown silk is the turning point, but a closer examination of the plant may be necessary.

“Go out and evaluate your fields. I would encourage producers to cut that ear open. That’s really how you tell,” he said.

“Most people go by brown silk, but even with a completely brown silk, a lot of times you’ll see several more green silks coming out. The only reason they’re growing out green silks is because it hasn’t pollinated yet.

“I’d encourage producers to cut the husk open with a pocket knife and gently pull off the corn husk and shake it. It is complete pollinated when the silks separate from the kernel.

“If you shake it and still one-third of those silks are connected to the kernels, you’re not fully pollinated yet.”

Kelley said it wasn’t a bad year thus far for insect pressure in corn across the 10 counties he serves between Champaign County and Sangamon County.

“As you move west and as you move north from that area, corn rootworm pressure does increase. I did not see the corn rootworm pressure in my area that I was expecting this year,” he said.

“So it hasn’t been that bad. Now that’s not to say that we don’t need to be scouting our fields and evaluating the performance of either the trait or the traditional chemistry practice that farmer used to try to manage corn rootworm.”

For the late-planted corn that has yet to reach maturity, Kelley said the three-part threshold to consider for corn rootworm adult beetles in determining a need for insecticide are whether pollination occurred, five beetles per plant and silk-clipping within a half-inch of the ear tip.

“We have to have all three of those happening before it warrants a spray for the control or management of corn rootworm adults,” he said.

“For the most part, we’re well past that, but it doesn’t mean that we can’t go out there with our shovels and evaluate what kind of beetle pressure we have, evaluate what kind of silk-clipping that we did have.”