The older larvae bore into the stalks and ears where they overwinter. Infested corn stalks may break or have weakened tassels that are easily broken by the wind. All of the above-ground parts of corn plants can be damaged by the larvae. If 3 or more moths are observed when walking through a grassy field edge, egg laying in the adjacent corn field is or was probably intense. Close inspection for egg masses or newly-hatched larvae should begin immediately.
Entomologists use blacklight traps or pheromone traps to monitor adult corn borer activity.
Mowing after harvest may be an alternative to ploughing down corn stubble. Chopping corn stalks for silage will remove and destroy the larvae. Burning is not as effective because some borers will survive in stalks not completely burned. Dwarf corn seems to be less susceptible to corn borer infestation than tall corn. High clearance sprayers or aircraft, fitted with multiple nozzles to ensure thorough coverage, are most effective when high water volumes are used.