J. Green, A. Dreves, B. McDonald, and E. Peachey


Winter cutworm is the common name for the larval stage of the large yellow underwing moth (Noctua pronuba [Lepidoptera: Noctuidae]). The cutworm has tolerance for cold temperatures, and larval feeding activity persists throughout fall and winter.

Adult N. pronuba moths have been detected in Oregon for at least a decade, and the species is common in many different ecological habitats. Epidemic outbreaks of adult moths have occurred periodically in this region, resulting in captures of up to 500 moths per night. However, larval feeding by N. pronuba has not been a problem in Oregon until recently. In 2013 and 2014, there were isolated instances reported, including damage by larvae to sod near Portland and defoliation of herb and flower gardens in Corvallis. In 2015, large numbers of larvae were observed around homes, within golf courses, and in field crops located in Oregon and Washington.

Winter cutworms have a wide host range across agricultural, urban, and natural landscapes (Table 1, page 2) and are a concern as a potential crop pest that can cause considerable damage in a short amount of time. Above-ground damage occurs when larvae chew through tissues near ground level, cutting the stems off plants. Leaf chewing and root feeding also have been observed. Winter cutworms are gregarious, which means they feed and move in groups, similar to armyworms. The severity of plant damage they cause can differ depending on specific environmental conditions, proximity to other host plants, and management practices.

This publication highlights general information about winter cutworm, including identification, scouting recommendations, and potential control measures.

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