By Adam Varenhorst and Philip Rozeboom et.al
A large majority of corn in South Dakota is still in the V1-V4 growth stages, with the most recent USDA South Dakota Crop Progress and Condition indicating that corn was 70% emerged. This means that a lot of corn in South Dakota is still susceptible to black cutworm feeding injury.
Black cutworms are a migratory moth that moves into South Dakota during early spring from the Southern United States. Although black cutworm caterpillars cause minor injury to corn by feeding on leaf tissue, the serious injury occurs when caterpillar feeding results in the cutting of young corn plants. This cutting activity can lead to considerable stand loss and the possible need to replant sections of an infested field.
Fields with residue or weeds are more attractive to the moths, which may result in increased risk. No-tilled fields and low-lying areas are typically the most attractive to the black cutworm moths. Other states in the region have detected black cutworm moths, which means it is likely that the moths are also in South Dakota.
Source : sdstate.edu