They are pale gray to reddish brown with mottled pigmentation and light gray, V-shaped markings on the back. They are most often found in fields following or adjacent to legumes or with heavy crop residue. A key characteristic is that on the top of each abdominal segment there are two sets of paired spots which are unequal in size ( Figure 1).ĭingy cutworms overwinter as small larvae and are usually the first to damage corn in the spring. The head has two black stripes and there is a pale band along the top of the body. When viewed through a hand lens the skin has a rough pebbly texture. Although there is more than one generation per year, the first generation is the only one causing significant damage to corn.īlack cutworm larvae are light gray to nearly black in color with an overall greasy appearance. When weeds are destroyed by cultivation or herbicides, cutworms move to newly emerged corn where damage soon appears. Variations in wind direction and speed (which affect the migration and ultimate distribution of the moths), stage of corn development, and local environmental conditions are factors that strongly influence the severity of black cutworm infestations. Moths migrate northward from southern states in early spring and deposit eggs on grasses, broadleaf weeds, and crop residue before corn in planted. Black cutworms do not overwinter in Nebraska.
Identification and Life History Black cutwormsīlack cutworms cause most of the serious cutworm problems in eastern Nebraska, but are seldom found west of the 100th meridian, which runs through Dawson County. Other less common cutworm species include sandhills, glassy, spotted, and bristly cutworms, and occasionally army cutworms and pale western cutworms in western Nebraska. Dingy and black cutworms are the species most often associated with damage to corn in eastern Nebraska, although darksided cutworms also may be important in northeast and western counties.
Fields with heavy plant residues or early season weed growth also are susceptible to cutworm attack. Central and western Nebraska corn may be affected by cutworms when corn follows sod, pasture, alfalfa, soybeans, small grains, or winter cereal cover crops. Severe cutworm damage to corn is rare in Nebraska and usually is confined to localized areas in eastern Nebraska. They are commonly referred to as cutworms and may reduce plant stand and yield if abundant. Several types of caterpillars feed on seedling corn and may cut the stem. Diagnostic features to identify black cutworms.
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