Borer entrance holes in larger pods allow water to enter, resulting in fruit rot. When rotting begins, borers often leave and move to infest new fruit. In this way, one larva can damage several pods. In addition, plants may break due to tunneling by the borers in the stems. European corn borer moths tend to congregate in tall grassy areas around field margins, called action sites.
Females fly into fields at night to lay their eggs.
Weather conditions during egg laying can greatly affect the severity of corn borer problems. Calm warm nights are most favorable for moth activity while few eggs are laid on windy, stormy nights. European corn borer eggs are laid in masses of 15 to 30 eggs per mass. Eggs are round and flattened and overlap each other like fish scales. Often they are placed on the underside of the pepper leaf near the midrib.