In August or September the adult moths emerge, mate, and deposit their eggs on suitable host plants. The common stalk borer passes through only one generation per year. Overwintering larvae become active in the spring and feed on corn in a manner similar to cutworms. The larvae pupate in silken cocoons in June or July, depending on the species. After a brief pupation period, the adults emerge and eggs are laid around grass stems.
Webworms pass through one or more generations per year depending on the species.
However, damage to corn is done primarily by the overwintering larvae which feed on corn in the late spring. Field Sampling Weekly inspection for early season pests should be initiated immediately after initial corn emergence. Inspect 100 plants at 3 to 5 locations selected at random in a field. During the inspection process, record number of plants damaged or infested per each 100 plants checked. Upon completion of field inspection calculate and record the percent damage or infestation found.