How Do You Estimate Corn Rootworm Pressure Using Yellow Sticky Traps?

August 8, 2023

Farmer holding a sticky trap
Farmer holding a sticky trap

Assessing adult corn rootworm activity with yellow sticky traps is an important scouting tactic and is key to staying ahead of the threat. If you haven’t set traps before, you can learn more here. Reading the results of those yellow sticky traps does require some math. While crunching numbers isn’t everyone’s favorite part of farming, calculating the average number of beetles in your fields is easy with this equation.

Estimating Your Pressure

1. Add up the total number of beetles collected.

2. Divide by the total number of traps.

3. Divide by the number of days.

4. If the answer equals two or greater, you've reached the potential threshold. This means a high corn rootworm population is expected the following season and action is recommended.

Example: 94 total corn rootworm divided by 6 traps equals 15.67, divided by 7 days equals 2.24

Defending Against Corn Rootworm with the Right Trait.

Once you’ve determined your corn rootworm risk, it’s time to think about your corn rootworm defense. Bayer offers innovative trait options for farmers with pressure ranging from low to high. See which one is right for you.

VT4PRO with RNAi Technology logo
VT4PRO with RNAi Technology logo

VT4PRO™ with RNAi Technology** will offer the widest spectrum of insect defense from Bayer with protection against above- and below-ground corn pests. It is recommended for fields with low to moderate corn rootworm pressure.


SmartStax PRO with RNAi Technology logo
SmartStax PRO with RNAi Technology logo

SmartStax® PRO with RNAi Technology is the strongest biotech defense against corn rootworm* available. It is recommended for farmers facing high pressure from corn rootworm.


*69 2021 & 2022 Bayer Trials in the corn belt (KS, CO, NE, IA, IL, ND, SD, OH, MN, & WI) vs
Qrome® products in the 95-115 RM range with comparable trait packages.
Bayer is a member of Excellence Through Stewardship® (ETS). Bayer products are commercialized in accordance with ETS Product Launch Stewardship Guidance, and in compliance with Bayer’s Policy for Commercialization of Biotechnology-Derived Plant Products in Commodity Crops. Commercialized products have been approved for import into key export markets with functioning regulatory systems. Any crop or material produced from this product can only be exported to, or used, processed or sold in countries where all necessary regulatory approvals have been granted. It is a violation of national and international law to move material containing biotech traits across boundaries into nations where import is not permitted. Growers should talk to their grain handler or product purchaser to confirm their buying position for this product. Excellence Through Stewardship® is a registered trademark of Excellence Through Stewardship.

**VT4PRO™ with RNAi Technology corn products are expected to be commercially available for the 2024 growing season.

ALWAYS READ AND FOLLOW PESTICIDE LABEL DIRECTIONS. B.t. products may not yet be registered in all states. Check with your seed brand representative for the registration status in your state.

B.t. products may not yet be registered in all states. Check with your seed brand representative for the registration status in your state.

IMPORTANT IRM INFORMATION: Certain products are sold as RIB Complete® corn blend products, and do not require the planting of a structured refuge except in the Cotton-Growing Area where corn earworm is a significant pest. Products sold without refuge in the bag (non-RIB Complete) require the planting of a structured refuge. See the IRM/Grower Guide for additional information. Always read and follow IRM requirements.

Roundup Ready 2 Technology®
contains genes that confer tolerance to glyphosate. Glyphosate will kill crops that are not tolerant to glyphosate. Insect control technology provided by Vip3A is utilized under license from Syngenta Crop Protection AG. Herculex® is a registered trademark of Dow AgroSciences LLC. Agrisure Viptera® is a registered trademark of a Syngenta group company. LibertyLink logo® and LibertyLink® are trademarks of BASF Corporation. Respect the Refuge and Corn Design® and Respect the Refuge® are registered trademarks of National Corn Growers Association. Bayer, RIB Complete®, Roundup Ready 2 Technology and Design®, Roundup Ready®, SmartStax® and VT4PRO™ are trademarks of Bayer Group. All other trademarks are the property of their respective owners. ©2023 Bayer Group. All rights reserved.