Update on Corn Rootworm Hatch June 15, 2002 Last week, we received a report from Larry Bledsoe, an entomologist with Purdue University, regarding the anticipated corn rootworm hatch. Larry indicated that a colleague of his, John Obermeyer, found a second-instar corn rootworm larva on June 4. Based on this observation, they believe that hatch began on May 31 for larvae found at the latitude of Tippecanoe County, Indiana. While troubleshooting fields because of crop injury, don't be surprised to find small corn rootworm larvae. The larvae are quite small; head capsule widths are 0.2-0.23 millimeter, 0.3-0.35 millimeter, and 0.45-0.5 millimeter for first, second, and third instars, respectively. The hatch will proceed for approximately 2 to 3 weeks, as not all larvae emerge from eggs at the same time. Following the larval stage of development, pupation occurs within an earthen cell. The pupal stage lasts from 6 to 13 days. In most years, the first sightings of adult corn rootworms occur near the 4th of July celebration. Let us know when you begin to find corn rootworm injury in your fields. Also, we would like to know how your soil insecticides are "holding up" this year.--Mike Gray Author: Mike Gray

The Pest Management and Crop Development Bulletin
Executive Editor: Kevin Steffey, Extension Entomologist

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