Western Bean Cutworm: What You Need To Know This Season

As corn harvest is around the corner, it’s important to be aware of some of the later season pests. One such insect is the Western Bean Cutworm, which is a moth species that’s endemic to the Western parts of the United States, but has recently (since 2000) spread to states including Indiana, Iowa, Minnesota, Illinois, Missouri, Wisconsin, Michigan, and Ohio.

The one generation of annual Western Bean Cutworm feeds on corn and soybeans and typically flies from early July through the end of August, meaning we still have several weeks of flight time left for the insect yet this growing season.

Identifying and proactively treating the Western Bean Cutworm is critical to ensure your corn yield isn’t negatively affected by the pest. In this article, we’ll explore how to identify the pest, what to look for in terms of damage, and share a few prevention tips.

Identifying the Western Bean Cutworm

What should you look for when identifying the insect? Purdue University shares the following key identifications of the pest, including:
● Primarily grayish-brown in color with a wing-span of approximately 1-1/2″
● Whitish stripe at the front of the forewing with two cream-colored, outlined shapes immediately behind
● Circular spot approximately halfway along length of forewing
● A kidney-shaped mark along the same line, approximately 2/3 of the way to the wingtip

The Western Bean Cutworm eggs are laid on upper surfaces of leaves, often on leaves near the whorl that have not unfolded completely. The eggs are laid in masses of 20-200, but usually average around 50 and within a week, eggs develop a purple coloration, indicating that hatch is imminent. Soon, larvae will move into protected areas of the corn plant, feeding on leaf tissue, fallen anthers/pollen and silks on their way to their destination: the developing ear of corn.

Purdue University developed a Life Cycle chart of the Western Bean Cutworm specifically for Indiana, detailing out the the stages including pupae, egg laying, larvae, adult, along with the “Time of Attack to Corn” eye chart:

Damage caused by the Western Bean Cutworm

The damage caused by the insect can be severe, but also patchy, depending on where the pest feeds. Purdue University explains that sometimes, multiple larvae may feed on a single plant or ear of corn, thereby causing extensive damage to that plant. In addition, there is likely considerable inter-plant movement early in life which results in infestation of nearby plants as well. It’s important to note that most feeding (and therefore damage) is concentrated on the ear of corn.

Purdue’s yield studies conducted in Iowa and Nebraska have shown that an average of one larva/plant throughout the field may cause yield loss of approximately 4 bu/acre.

What is the damage you can expect from the Western Bean Cutworm?
● Prone to various types of molds
● Decreased grain quality of food-grade corn varieties
● Dry husks (most noticeable at harvest)

Prevention Tips for Western Bean Cutworm

1. Identify whether your region is predicted to (or already does) have issues with the Western Bean Cutworm this season
2. Become familiar with the signs of what to look for as it pertains to the various generations of the Western Bean Cutworm
3. Deploy an electronic smart trap, like Spensa’s Z-Trap in partnership with Spectrum Non-GMO Seed, to automate the process of insect trapping and counting for pests like the Western Bean Cutworm, European corn borer, and Corn Earworm
4. Use a scouting solution, like Spensa’s OpenScout, or employ a scout to accurately track, monitor and make important control decisions throughout the entire growing season

Will Your Crop Be Affected by the European Core Borer?

Want to be able to trap the European corn borer and make better, more informed decisions about your crops? Learn more about how Spensa’s Z-Trap, in partnership with Spectrum Premium Non-GMO here.

Spensa Unveils Dynamic Phenology™

Our team at Spensa has just unveiled Dynamic Phenology™ capabilities, which is the latest update to the company’s Trapping Insights, an enhanced pest-management decision-making solution. The new capabilities allow growers and agronomists to predict timing for insect life-cycle events such as when they hatch and when they fly. This timing data is critical for effective use of pesticide. Unlike traditional phenology prediction models, Dynamic Phenology™ incorporates real-time weather data and pest observations to sustain a much higher degree of accuracy.

Our mission at Spensa is to create technologies to better control insects, weeds, and disease, and unveil new capabilities to help ag professionals predict with increased certainty how to prepare for and treat insect issues. Unlike traditional phenology models which start from an assumed population distribution based on historical data, our Dynamic Phenology™ makes use of current trap data from a specific field to accurately predict future insect stages.

Changes in insect phenology have occurred and will continue to occur due to insecticide pressure, changes in climate, and regional differences. Dynamic Phenology™ automatically compensates for these changes to get a solution that is custom for each field. The capabilities are part of our Trapping Insights, an enhanced decision-making solution that can be used alongside the Z-Trap and MyTraps products. With Trapping Insights, users also gain access to additional features including pest alerts and a degree day calculator.

The Dynamic Phenology™ technology update was also accompanied by the release of the Spensa Agronomic Platform (Spensa AP), which integrates precision ag products into a single, easy-to-use interface.

See the full press release issued by Purdue University Research Park News.

Introducing the Spensa Agronomic Platform

Today we are excited to share that the product update to OpenScout is live! This update will make it easier than ever to access your important OpenScout data. See below for an explanation of the update as well as instructions for how to log-in and access your application and data.

What is the Spensa AP and why is it important?

The Spensa AP is simply an update to the same great OpenScout solution you’re already using. However, with the Spensa AP’s capabilities, we will be able to offer you even more decision tools in the future. Now you will be able to gain access to all of your current Spensa apps from a single location via the Spensa website.

As of today, January 16th, simply log-in to the Spensa AP by visiting: ap.spensatech.com with your existing OpenScout credentials.

If you have any questions, please feel free to call anytime at 765-588-3592 or send an email to info@spensatech.com.