Corn earworm (Helicoverpa zea) is a type of caterpillar that feeds on corn ears, causing significant damage to kernels. Infestations can result in yield losses of up to 30%, making corn earworm a formidable threat.
But with proactive scouting strategies and quick action with chemical treatments like Willowood Lambda-Cy 1EC and GCS Bifenthrin 2EC, control is achievable.
(Image Credit: Ward Upham, Kansas State University, Bugwood.org)
How Does Corn Earworm Affect Corn Crops?
Corn earworm larvae have a voracious appetite for corn kernels, directly impacting the development of the ears and creating entry points for secondary infections. Severe infestations can even extend beyond the ears to the stalks and tassels, further compromising overall plant health and productivity.
Identifying Corn Earworm
Adult corn earworm moths have a wingspan of about 1.5 inches and can vary in color.
However, it is the larval stage that causes the most damage. These larvae are typically pale green or brown with longitudinal stripes along their body.
To identify the presence of corn earworm:
Closely inspect the silks, husks and kernels for signs of larvae or feeding damage
Look for chewed silks, holes in the husks and kernels, and the presence of frass
Monitor for any signs of secondary infections, such as discoloration, mold or decay
(Image Credit: Ward Upham, Kansas State University, Bugwood.org)
Regions Typically Affected by Corn Earworm
Corn earworm is widespread across the United States, particularly in the southern and eastern parts of the country. However, it can also pose a problem in other regions, especially during periods of migration.
When Does Corn Earworm Affect Crops?
Corn earworm can be present in corn fields at any point during the growing season. Early-season infestations are often caused by overwintering populations, while late-season infestations result from migration.
(Image Credit: Eugene E. Nelson, Bugwood.org)
How to Chemically Manage Corn Earworm
When deciding whether to employ chemical products to control corn earworm, farmers should first assess the severity of the infestation and determine the economic threshold for treatment.
Once fields have reached a level of infestation at which chemical products are needed:
One popular option is Willowood Lambda-Cy 1EC**, an insecticide containing lambda-cyhalothrin.
Another option is GCS Bifenthrin 2EC**, which is another insecticide containing bifenthrin with similar label applications.
Several chemical products containing insecticides with active ingredients such as spinosad are effective against corn earworm.
Consider integrating other management practices alongside chemical control, such as crop rotation, biological control, and pheromone traps, to enhance effectiveness and reduce reliance on insecticides. Rotating between different modes of action helps prevent the development of resistance in corn earworm populations, ensuring long-term sustainable pest management.
Disclaimer
© 2014 - 2024 Farmer's Business Network, Inc. All rights Reserved. The sprout logo, “Farmers Business Network”, “FBN”, “FBN Direct” are trademarks or registered trademarks of Farmer's Business Network, Inc. This content was written by Norm℠, reviewed and edited by Mikaela Tierney.
**RESTRICTED USE PESTICIDE Due to acute toxicity. For retail sale to and use by certified applicators only – NOT to be used by uncertified persons working under the supervision of a certified applicator.
FBN Direct products and services and other products distributed by FBN Direct are offered by FBN Inputs, LLC and are available only in states where FBN Inputs, LLC is licensed and where those products are registered for sale or use, if applicable. If applicable, please check with your local extension service to ensure registration status. Nothing contained on this page, including the prices listed should be construed as an offer for sale, or a sale of products. All products and prices are subject to change at any time and without notice and excludes CA mills tax and MN ACRRA fees. Terms and conditions apply.
