How to Manage Corn Earworm

FBN Network

Sep 01, 2023

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.

Ward Upham, Kansas State University,

This post will outline: 

  • How corn earworm affects crops 

  • How to identify corn earworm 

  • Regions typically affected by corn earworm 

  • When corn earworm usually affect crops

  • Chemical products to control corn earworm 

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. 

Ward Upham, Kansas State University,

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

[RELATED: What’s the Difference Between Conventional, GMO, Non-GMO and Organic Corn?]

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. 

Eugene E. Nelson,

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. 

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.

[RELATED: How to Manage Hail Damaged Corn]

Protect Crops from Corn Earworm with FBN Direct®

Proactively scouting for and responding to pest presence in your fields will help reduce potential crop damage and improve yield. FBN Direct has a wide variety of effective insecticides to help address pest pressures and keep your operation on track. With transparent pricing, straightforward online ordering, detailed product labels and fast direct-to-farm delivery, FBN Direct can help you get the products you need to protect your crops. 

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