SCOTTS BLUFF COUNTY, Neb. – Nebraska has many different types of cutworm species depending on location and many of them live in the soil as larvae during the winter. The extremely cold air temperatures recently have brought about questions regarding the population for this year.

“One thing that we see fairly constantly is that when it does get cold, if you have snow cover, that snow cover can insulate the soil from experiencing those extreme colds,” said Jeff Bradshaw, Interim Director and Entomologist at the Panhandle Research and Extension Center. “It can take fairly extremely cold temperatures and open soil for those low temperatures to have an impact.”

Bradshaw explained that for temperature to have a meaningful impact, there would be multiple days in a row with freezing cold temperatures and no snow on the ground. 

“In a lot of places across the state, what we’ve seen so far, is the soil temperatures haven’t dipped that low,” said Bradshaw. Wet weather can also play a part in over-wintering insect populations.

Two of the main cutworms that are found in this area are the army cutworm and the western bean cutworm and telling them apart can be difficult. One way to know is the markings on their bodies. Another way is the time of the year that the adult moths and the new larvae occur.

Bradshaw said, “Army cutworm populations are going to be flying in May and June mostly and then western bean cutworms for example will start flying in July.” 

Food sources also differ due to the time of year that the adults are flying. 

“Army cutworm, the larvae are going to feed on early spring crops, maybe alfalfa and wheat for example,” said Bradshaw. “The western bean cutworm, being a later season insect, it mainly just attacks dry beans and corn as a larva.”

A project that Bradshaw is currently working on is predicting populations for the western bean cutworm. 

Bradshaw mentioned that the non-migratory western bean cutworm population has been fairly high for the past three years and data for this year is still being compiled.

“We’re trying to figure out what trapping methodology might work best in terms of accuracy and precision for helping us understand the risks that our dry bean fields are, and our corn fields are to western bean cutworm injury,” said Bradshaw.

For more information, contact Jeff Bradshaw at (308) 632-1230.