Skip to Main Content

Manage Western Bean Cutworm in Corn Crops

Categories: GROWING, CORN
Western bean cutworm (WBC) is native to North America and is a severe pest in several areas of the Corn Belt. Traditionally a pest of the western Great Plains, WBC has moved east into much of the Corn Belt. While populations may vary from year to year, this corn pest is a consistent threat in some corn growing regions. Egg masses of up to 200 eggs can be laid in the upper plant leaves and mature quickly over a few days. It is common to find multiple western bean cutworm larvae feeding per ear, because they are not cannibalistic (unlike corn earworm).

Scouting and Treatment
Infestations of WBC are often patchy and may occur over a span of several weeks, requiring multiple scouting visits and creating challenging treatment decisions. There are multiple options for scouting which include pheromone traps, using degree days to predict moth emergence, black light traps and actual scouting of corn plants. When scouting corn plants, check 20 plants in a minimum of 5 areas in each field for egg masses. Inspect the upper 1/3 surface of plant leaves for eggs. Eggs will be grouped into 15 to 50 individual eggs, laid in flat, irregularly shaped masses. Each egg will be about the size of a pin head. Eggs darken as they mature, changing from white with a thin red ring to brown, purple and eventually turning black before hatching. Egg color can help predict egg hatch and proper timing of foliar insecticides. This is important as timing of insecticide treatments can be difficult due to moth flights and egg laying spread over time, resulting in multiple hatch timings. Proper timing of insecticide application is also critical, as larvae will quickly migrate to developing kernels within the husks after hatch. After larvae enter the ear, they are protected from insecticides, making delayed applications ineffective. 

Plant Damage
Upon egg hatch, young larvae feed mainly on pollen within tassels and eventually move down into developing silks. Once pollination is complete, WBC will quickly move inside the ear husk and feed on developing kernels. Holes in husks are often visible from entering and exiting of ears. Larval feeding affects corn yield and reduces grain quality through damaged kernels and resulting mold and mycotoxin development. Kernel quality degradation can negatively affect the price of grain and can be potentially harmful to livestock.

Protect Your Hybrids
Agrisure Viptera® is the only trait available today that effectively controls WBC. It is the best option on the market to consistently limit damage and protect grain quality. By controlling major leaf-, stalk- and ear-feeding corn insects, including WBC, Agrisure Viptera trait stacks offer better crop stand and lower levels of disease, resulting in increased yield and profit potential.

Speak to your Golden Harvest Seed Advisor to learn more about the effective, comprehensive insect control of Golden Harvest hybrids with Agrisure Viptera.

Photos are either the property of Syngenta or used under agreement.
Syngenta hereby disclaims liability for third-party websites.

Contact a local seed advisor


You are viewing from

Thank you for visiting the Golden Harvest website. We understand how important it is for you to find agronomic and product information pertinent to your local area. Please enter your zip code or select your area below to ensure you are seeing the information that matters most to you.
Learn more about regions >


We’re sorry. Golden Harvest is not available in this area. Please try another zip code or contact a Golden Harvest Seed Advisor for more information.

Is this page helpful to you?

How can we improve
this page? (optional)

Can you tell us your
role in agriculture? (optional)

Thanks for the feedback.

We appreciate your participation