While the most effective method of timing insecticides is by scouting for corn borer eggs, it is a very difficult task. Use of pheromone trap collections may provide a good indication of when to initiate scouting. If scouting is attempted one method is to cut 20 plants from each of five locations in a field. Plants should be removed from the field, taken to a place more fit for human endeavor and foliage searched. For first generation corn borers, granular insecticides are often chosen.
Granules likely drop into the whorl better than water based sprays.
Granular insecticides are not effective against second generation corn borer. For second generation larvae sprays are the preferred choice. Spray volume is very important. In 1999 correctly timed foliar sprays provided acceptable levels of corn borer management when applied in 20 gpa. Another method of foliar insecticide application that should be successful is through center pivot irrigation where available.