Elaine Roddy, Vegetable Crops Specialist – Ridgetown, OMAFRA
Several cutworm species are already active in Ontario fields. The size of the cutworms combined with the delayed growth of the plant, makes many crops a prime target for damage. Adult cutworm moths migrate to Ontario in the early spring. They often lay their eggs in winter annual or perennial weeds. Scout sweet corn fields for early signs of damage. Look for cut or wilted plants. The culprit is often found under the soil surface at the base of the damaged plant. The threshold in sweet corn is 10% damaged plants, if the cutworm larvae are less than 1.5” in length. Larger larvae have generally stopped feeding and are preparing to pupate. Once the corn crop reaches the 5-6 leaf stage, it is much less susceptible to cutworm damage.