Figure 1. Management worksheet for first-generation European corn borer.

NOTES:

1 Record all percentages as decimals (for example, 20% = 0.2).

2 If larvae are newly hatched (first instar), it is likely that
only about 20% will survive to maturity, depending on environmental
stresses. If larvae are second instar (about 3/16 inch) or larger, the
survival rate may increase to 50%. Adjust this number accordingly.

3 Use 0.06 for V10 corn, or 0.05 for V16 (green tassel) corn.
When borer numbers reach or exceed three per plant, the loss caused
by each additional borer will decrease. Therefore, use 0.035 loss per borer
for each additional borer above three per plant.

4 80% control with granules (aerial or ground application) and
with sprays directed over the whorls (ground application); the more
effective insecticides provide comparable control when applied as broadcast
sprays (aerial application).