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Keep your eyes out for western bean cutworm moths

Keep your eyes out for western bean cutworm moths


It’s that time of year again when western bean cutworm moths start making their way across Nebraska. Scouting is going to be important during the next few weeks to determine if management decisions need to be made.

Adult moths prefer to lay their eggs in corn fields in the late whorl to early tassel stage. Moth flights are temperature sensitive and predicted patterns may vary depending on environmental conditions.

Scout fields regularly in the coming weeks to determine if treatment is warranted based on economic thresholds. These thresholds are met when 5 to 8% of corn plants have egg masses and/or larvae present. If an insecticide application is needed, time the application after 95% of plants have tasseled but before the larvae nestle into the silks where they are well protected.

UNL has several black light stations around the state to help track moth flights with the closest traps located in North Platte and Clay Center. A more extensive list of locations, predicted flight patterns, black light trap data, and economic thresholds can be found on UNL’s Western Bean Cutworm Central website:

Nebraska 4Rs Nutrient Stewardship Field Day

Nutrient management is critical for soil health, crop yield and protecting water quality. Nebraska Extension is hosting the 4Rs of Nutrient Stewardship Field Day on Thursday at the Eastern Nebraska Research, Extension, and Education Center near Mead.

This free field day will run from 9 a.m. to 3 p.m. and will include various topics surrounding the 4Rs of Nutrient Stewardship including variable rate nitrogen applications, sensors, manure management, water quality, crop model-based tools, soil health and in-field demonstrations.

Continuing Education Units are available for nutrient management. Lunch is included in this free field day, but pre-registration is requested for an accurate head count.

A list of, opics, and the registration link can be accessed at

Questions can be directed to Javed Iqbal, Extension specialist, at 402-472-1432 or

Japanese beetles

Japanese beetles have been spotted in Nebraska on landscape trees and shrubs this year. Over the coming weeks, we should gradually see more beetles invading row crop fields in this area.

While these beetles only have one generation per year, they can cause serious defoliation to row crops if not monitored. The economic threshold for Japanese beetles is different depending on if the crop is in the vegetative or reproductive stages.

In soybeans, Japanese beetles skeletonize leaves reducing sunlight capture and photosynthetic capabilities. An insecticide treatment may be warranted when defoliation exceeds 30% in the vegetative stages and 20% in the reproductive stages in soybeans.

In corn, Japanese beetles scrape off the upper leaf surface in the vegetative stages. Once silks have emerged in the reproductive stages, beetles start clipping silks which can inhibit pollination. An insecticide treatment is typically not warranted in the vegetative stages but can be considered during the reproductive stages if all three of the following criteria are met: three or more Japanese beetles per ear, silks clipped to less than half inch, or pollination is less than 50% complete.

Several foliar insecticide active ingredients are available if a treatment is necessary for either corn (i.e., indoxacarb, alpha-cypermethrin, and gamma-cyhalothrin) or soybeans (i.e., permethrin, clothianidin, and bifenthrin). Make sure to read labels carefully for desired rates.

More information can be found on UNL’s CropWatch website.

Sarah Sivits is the Dawson County Extension educator in crops and water, and serves Dawson, Buffalo and Hall counties. Contact her at 308-324-5501 or by email at

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