Stalk borers can destroy a corn stand under these circumstances. Be sure to read the insecticide label before mixing pesticides. In some of our experiments, we have found that Bt corn suppresses or slows down stalk borer injury. Bt corn does not have the same effect on stalk borers as it does on European corn borers, so don't expect complete control of this pest in Bt corn. If the number of infested plants exceeds the percentage given for the plant stage, then an insecticide application can be economically justified.
Young plants have a lower threshold because they are more easily killed than older plants.
Scouting is not necessary beyond the V7 developmental stage. These products, with the exception of Lorsban, are restricted use pesticides. Always read and follow label directions. This information subject to a usage policy .