Here’s How You Can Manage Insects That Overwinter in Your Corn Fields

LeRoy Toohey

Nov. 21, 2019

Your corn crop can face many different insects throughout the growing season, and it seems like they always arrive when the crop is at its most vulnerable growth stage. 

Insect pests have evolved their life cycles to match corn development stages. And many of the most detrimental insects overwinter in plant residue, fencelines, waterways or wooded areas, just waiting for the chance to attack. 

Learn which insect pests overwinter 

Some pests overwinter in northern climates as eggs, larvae, pupae or adults. These include: 

  • Western Rootworm 

  • Northern Rootworm 

  • European Corn Borer 

  • Western Bean Cutworm 

  • Wireworms 

  • Japanese Beetle 

  • True White Grubs 

  • Corn Flea Beetle 

  • Common Stalk Borer 

  • Seedcorn Maggot 

  • Stinkbugs 

  • Differential Grasshopper 

  • Billbug 

  • Two-spotted Spider Mite

Insect pests that cannot overwinter in northern regions due to cold temperatures include:  

  • Southern Rootworm 

  • Black Cutworm

  • True Armyworm

  • Fall Armyworm

  • Corn Leaf Aphid

  • Corn Earworm

Pay close attention to certain variables 

It is important to understand how insect pests impacted your operation this year. Most insect populations vary from year to year depending on many factors, including excessive moisture, drought, prevailing winds, tillage, winter survivability and other environmental conditions. 

Winter temperatures greatly influence whether or not an insect can overwinter in northern regions. There is no set line separating northern and southern regions in the U.S. when it comes to overwintering pests. In some years, Kansas and the southern parts of Missouri and Illinois can be considered part of the southern region if winter temperatures are moderate. 

Build your strategy to prepare for next year

Understanding which pests were present this season is important when making sound decisions for the next. And, as always, timely scouting throughout the year is key any effective management strategy. 

1. Know the limitations of traited seed

You might have planted fully traited seed in the past in hopes of protecting your crop from insect damage. But while fully traited seed is effective at managing some insects, these seeds can be expensive and will not protect your crop from all insects. Don’t be fooled into thinking that planting traited seed is the be-all and end-all of your insect management strategy. 

2. Use common tillage practices wisely

Conventional tillage in the fall and spring is a good tool to use when trying to minimize overwintering insect pests. Burying residue—where many overwintering insect pests live—helps to lower overwinter survival numbers. Keep in mind that you must balance tillage practices with other agronomic concerns, such as erosion and overall soil structure. The more you till the soil, the more soil structure loss you’ll see. 

3. Take a look at seed treatments and herbicide applications

Seed treatments are a great tool for protecting against early-season pests, too, and insecticides applied post-emergence when needed can also protect your investment.

Here are a few great post-emergence insecticides:

Below-ground insecticide options at planting time include:

Remember to ALWAYS read and follow label instructions. Perform a compatibility jar test prior to mixing any products in your sprayer tank.

Reviewing your scouting records and understanding which insects overwinter—and which ones don’t—will help you be proactive heading into the next growing season.

Want to step up your field scouting game?

Scouting your fields can provide you with greater insight into building an effective management strategy. Download our free Precision Mapping Guide to see how you can use data-driven insights on your operation.

ALWAYS READ AND FOLLOW LABEL DIRECTIONS. It is a violation of federal and state/provincial law to use any crop chemical product other than in accordance with its label. The distribution, sale and use of an unregistered pesticide is a violation of federal and/or state law and is strictly prohibited. It is your responsibility to confirm prior to purchase and use that a product is labeled for your specific purposes, including, but not limited to, your target crop or pest or weed, and its compatibility with other products in a tank mix.

Willowood Lambda 1EC, Willowood Bifenthrin 2EC  are registered trademarks of Willowood USA. Cruiser®, Force® and, Warrior® with Zeon® Technology are registered trademarks of Syngenta Crop Protection, LLC. Sniper® is a registered trademark of Loveland Products, Inc. Lorsban® Insecticide is a registered trademark of Dow AgroSciences LLC. Capture® LFR and Astro® Insecticide are registered trademarks of FMC Corporation. Asana® XL Insecticide is a registered trademark of DuPont Crop Protection. Poncho®, Baythroid® XL and Sevin® SL are registered trademarks of Bayer CropScience. Bifenture® LFC is a registered trademark of UPL NA Inc.

"Western corn rootworm" by entogirl is licensed under CC BY 2.0

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LeRoy Toohey

Nov. 21, 2019