Scouting for European Corn Borer (ECB)
Before scouting, verify from field records where Bt corn and non-Bt refuge have been planted.
Follow these steps to scout for ECB twice a season – once when the corn is waist high and a second time at or shortly after pollination:
1. Scout the refuge (non-Bt) first.
Check corn plants for ECB feeding by randomly counting 10 consecutive plants (one set), move over 20 rows and 20 paces down the row and count another set of 10 plants. Do this until you have counted 10 sets (10x10) or 5 sets of 20 plants (5x20) for a total count a total of 100 plants. Work with what best fits the field shape but still delivers a random sample of the field.
2. Identify ECB feeding damage.
First Trip: When the corn is waist high, look for pinhole and shot hole damage on the leaves and whorl of the plant.
Second Trip: Shortly after pollination, look for frass at the leaf axils, bent leaves at the midribs, broken tassels, and lodged plants.
3. Record
Record the number of plants with feeding on the worksheet provided.
4. Repeat.
Repeat the above procedure in the Bt corn after the refuge has been scouted. Count 100 plants per 40 acres in 10x10 or 5x20 sets. For each 10 acres over 40, count an extra 25 plants. (Example 60 acres = 150 plants). Identify ECB feeding and record the number of plants with feeding.
5. Compare
Compare damage levels in the non-Bt refuge and the Bt corn hybrid area.
What to do if more than 5% of plants have damage