Larvae also can tunnel into corn stalks below the growing point, but this does not kill the plant. Chemical control is difficult to achieve because larvae are exposed for very short periods of time, and they cannot be killed after tunneling into a plant. Time an insecticide with long residual action to coincide either with egg hatch or with movement from grass to corn. One approach is to target the hatching larvae. This is best suited for fields with a history of field-wide infestations.
Timing is critical.
This is when the stalk borers are hatching. Look at the degree day chart on the last page of the newsletter to determine if stalk borers are hatching in your area. The undesirable aspect of this approach, however, is that the size of the stalk borer population is not considered. An insecticide could very well be applied in the absence of an economically-damaging population. If the insecticide is not targeted against the hatching larvae, a second approach is necessary when a history of field-wide problems exists.