In March or April, they change into pupae. Approximately 10 days later, moths emerge, mate, and begin laying eggs at night, usually on the underside of lower leaves. The flat eggs are laid either singly or in small clusters of 2 to 25 overlapping one another like shingles. When the eggs hatch 7 to 10 later, larvae move into the whorl of the plant, feeding on the leaves and spinning a silken thread behind them. In the summer, southern cornstalk borers live from 20 to 35 days and develop through seven instars.
Mature larvae seal off the tunnels with frass and form cells in which to pupate.
Southern cornstalk borers have two generations per year. Southern cornstalk borers cannot survive the winter in uprooted exposed stalks. For specific information on insecticides and rates, consult the current North Carolina Agricultural Chemicals Manual .