By Scout Nelson
Nebraska researchers have confirmed that caterpillars found feeding in a western Nebraska sugar beet field are clover cutworms, not the beet armyworms that were first suspected. Correctly identifying crop pests is important because it helps growers choose the best management practices while avoiding unnecessary insecticide applications.
Pin-Chu Lai, Extension Entomologist; Kyle Koch, Assistant Extension Educator; Jeff Bradshaw, Director of the Doctor of Plant Health Professional Program; and Silvana Paula-Moraes, Extension Entomologist, explained that laboratory testing confirmed the insects after caterpillars collected from the field developed into adult moths. The identification provided valuable information about the pest and its potential impact on Nebraska sugar beet production.
Clover cutworm is a common cutworm species with a wide host range. The caterpillars feed on more than 20 cultivated crops, including sugar beet, corn, soybean, sunflower, canola, tomato, onion, cabbage, and alfalfa. Like many cutworms, they feed mainly at night, eat plant leaves, and may cut young plants near the soil surface.
Although clover cutworm looks similar to beet armyworm during the caterpillar stage, several important differences help separate the two species. Clover cutworms have different body stripe patterns and do not have the black spot behind the head that is a key feature of beet armyworm. Unlike beet armyworm, which migrates north each year, clover cutworm survives Nebraska winters as pupae in the soil and usually produces two generations annually.
This is the first known report of clover cutworm feeding in Nebraska sugar beet fields. Researchers believe the mild winter may have allowed larger populations to survive and develop during early summer. Fortunately, the affected producer reported that feeding lasted for less than one week and caused less than 25 percent defoliation. The sugar beet plants recovered after the feeding stopped.
Researchers also found beneficial Meteorus parasitoid wasps emerging from one of the collected caterpillars. These natural enemies attack caterpillars and help reduce pest populations without harming crops.
Photo Credit: University of Nebraska-Lincoln
Categories: Nebraska, Crops, Sugar Beets