How to Manage European Corn Borers in Corn

FBN Network

Aug 16, 2023

European corn borers (Ostrinia nubilalis) are voracious insects that can cause significant damage to corn crops, resulting in reduced yields and financial losses. 

By understanding the impacts of European corn borers, promptly detecting the pests and using products like Willowood Lambda-Cy 1EC** and GCS Bifenthrin 2EC**, farmers can protect crops and optimize their yields. 

In this guide, we will explore: 

  • European corn borer life cycles

  • How European corn borers affect corn 

  • How to identify European corn borers

  • The regions typically affected by European corn borers

  • When European corn borers usually affect crops

  • Chemical products to control European corn borers

Adam Sisson, Iowa State University,

What Are European Corn Borers?

The European corn borer is a species of moth with a four-stage life cycle: 

  • Egg

  • Larva*

  • Pupa

  • Adult moth

*Because European corn borers primarily damage corn crops at the larval stage, this is when control measures are applied. 

Depending on the region of corn production, there can be between one and four generations of ECB per year, although two generations per year is most common.

First Generation 

First generation European corn borer larvae overwinter inside corn stalks and corn cobs, which provide protection for the larva from weather and predators. In early spring, the larvae become active and convert into the pupa stage. 

Adult moths then emerge in mid-May through mid-June. They mate, and the female moth lays eggs in clusters of 5-30 eggs on the underside of corn leaves near the midrib. Eggs hatch in 4-10 days, and the larva feed in the whorls of the plant, which causes a shot-holed appearance on the leaves as they continue to grow.

As the larvae increase in size, they bore into the tender stalk, forming a cavity within the stalk. The larva then pupate and the second generation moth emerges 7-14 days later.

Second Generation 

Second generation European corn borer moths mate, and the female moth lay eggs on the underside of leaves. These lava hatch and feed on remaining pollen in leaf axils and also on corn silks. Eventually, the second generation larvae feed and enter the shanks of ears, ear tips and upper half of corn stalks.

[RELATED - 3 Types of Rootworm Beetles: What's the Difference?]

John C. French Sr., Retired, Universities:Auburn, GA, Clemson and U of MO,

How Do European Corn Borers Affect Corn?

European corn borer larvae tunnel into the stalks, ears and tassels of corn plants, weakening the plants, disrupting the flow of water and nutrients throughout the plant and creating disease entry points. This also makes corn more susceptible to lodging, especially during strong winds or heavy rains, which can lead to pest and disease vulnerability and severe yield losses. 

More specifically, European corn borer larvae harm crops through:

  • Stalk Damage: European corn borer-inflicted damage to the stalk can translate to harvest issues due to weakened, broken and lodged stalks. This also provides an entry point for additional insects and possible disease.

  • Shank Feeding: When European corn borer larvae feed on the ear shank, it may cause ear droppage and make the ear unharvestable. This can result in significant yield loss at the end of the season.

  • Ear Tip Feeding: Ear tip feeding by European corn borer larvae can lead to kernel loss, which will also impact your yield.

Frank Peairs, Colorado State University,

How to Identify European Corn Borers

European corn borer adult moths are relatively small with a wingspan of about one inch and a distinctive pattern of alternating light and dark bands across their wings. These moths are most active during the evening and night, making light traps or pheromone traps useful for spotting them. 

The larvae are cream-colored with brown heads and can be found tunneling through the stalks, ears, and tassels of corn plants. 

Several indicators can help identify the presence of European corn borers in corn fields, including: 

  • The characteristic "shot-hole" appearance on leaves, resulting from larvae feeding on foliage

  • Frass, the insect excrement, found near entry points such as holes in leaves

  • The presence of larvae inside stalks, ears, or tassels

Regions Affected by European Corn Borers

European corn borers are a widespread pest found throughout the United States, with the highest populations typically observed in the Midwest region. 

However, they can also be a problem in other corn-growing regions, including the Northeast, Mid-Atlantic, and parts of the South. 

Jan Samanek, Phytosanitary Administration,

When Do European Corn Borers Typically Affect Crops? 

European corn borers can be a persistent threat throughout the entire growing season, although their activity levels vary depending on the region and prevailing weather conditions. 

Early-season infestations are more prevalent in southern regions, while late-season infestations tend to be more common in northern regions. 

[RELATED: How to Manage Hail Damaged Corn]

How to Chemically Manage European Corn Borers

When deciding whether to employ chemical products to control European corn borers, farmers should first assess the severity of the infestation and determine the economic threshold for treatment. 

Regular scouting, monitoring, and timely intervention are key to minimizing damage caused by European corn borers and ensuring healthy and productive corn crops. 

European Corn Borer Crop Protection from 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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Hero Image: Jan Samanek, Phytosanitary Administration,

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FBN Network

Aug 16, 2023