Crop Protection Starts with Scouting

By Scout Nelson

As soil temperatures rise and vegetable planting begins across Minnesota, growers are being reminded to watch carefully for cutworm activity. Several species of cutworms appear during spring, and these pests can quickly damage young vegetable crops by feeding leaves and cutting plants near the soil's surface.

Black cutworms are one of the most destructive species found in Minnesota. Unlike some other cutworms, black cutworms do not survive the state’s winter conditions. Instead, they migrate north from southern states using seasonal weather fronts. Researchers use pheromone traps to monitor moth activity and predict when black cutworms may begin damaging crops.

Other species commonly found in Minnesota include winter cutworm, dingy cutworm, bronzed cutworm, and glassy cutworm. These species survive cold winters and emerge at different times during spring. Winter cutworms are especially cold tolerant and may appear even when snow remains on the ground.

Young cutworm caterpillars begin by feeding small sections of leaves before becoming large enough to cut plants. Early scouting is important because younger caterpillars are easier to manage before major crop damage occurs.

Growers are encouraged to inspect fields during dusk or early morning hours because cutworms are most active at night. If damage is visible but insects are not easily found, gently searching under the soil near damaged plants may reveal hiding caterpillars.

Researchers have also identified increased black cutworm risk in several Minnesota counties, including McLeod, Nicollet, Steele, Meeker, Redwood, and Dakota counties. Growers in these areas are advised to carefully monitor crops for leaf feeding and early signs of injury.

Cutworm management often depends on field conditions, covering crops, weed growth, and weather patterns. Fields with green plant material in spring may attract moths searching for egg-laying sites. Cover crops and grassy weeds can sometimes increase the chances of cutworm infestations.

Experts recommend regular scouting and timely insecticide applications when young caterpillars are present. The Midwest Vegetable Production Guide remains an important resource for pesticide recommendations and proper cutworm management practices.

Photo Credit: gettyimages-fotokostic