Corn borer populations remain low

Reports of European corn borers from across Iowa indicate that populations are very low. Hal Tucker, Tucker Consulting, reported several fields in Monona County in western Iowa with 20 percent of the plants infested. In eastern Iowa, Brad Buchanan, Crop Tech Services, Inc., found a few fields in Cedar County with 20-25 percent of plants with larvae.

In central Iowa, Jim Webster, Pioneer agronomist in Reinbeck, noted that his highest counts in Grundy County also were at 20 percent. Mike White, extension specialist-crops for south central Iowa, has commented that he did not think that corn borer populations could get any lower than those of the previous two summers, but that this season's population may set a new record low.

All of these field reports are good news for farmers, but cornfields, and especially early planted fields, still should be scouted for European corn borers. A quick way to check for this pest is to walk across the field and look for leaves with shotholes. If you find shotholes, then begin a more rigorous sampling procedure as outlined in the June 19 ICM newsletter, pages 108-109. At the end of the year, we can look at surveys from around the Midwest and determine how low the European corn borer populations really were for 2000.

Corn borer shotholes in corn leaves.

This article originally appeared on page 119 of the IC-484(16) -- July 3, 2000 issue.

Updated 07/02/2000 - 1:00pm