· Economic infestations of first-generation European corn borers have not been noted thus far.
Apparently everyone is out scouting for first-generation European corn borers, but most people are finding low levels of injury and only a few larvae in cornfields. Dennis Epplin, Extension Educator, Crop Systems in the Mt. Vernon Extension Center, observed newly hatched corn borer larvae in Jefferson County late during the week of June 14. Mike Roegge, Extension Unit Educator, Crop Systems in Quincy, is still finding egg masses in cornfields in western Illinois. He reported that infested fields are not widespread in his area. Brian Oester, Pioneer Hi-Bred International, reported that numbers of European corn borers in Clark, Crawford, and Lawrence counties are still quite low. Many fields have no sign of infestation, and the most injury he observed in seed cornfields late in the week of June 14 was 3 percent. At that time, he was finding first through fourth instars. Kevin Nelson, Utica Elevator Co., observed a very small infestation (1 percent of the plants infested) in LaSalle County during the same week. And, believe it or not, I had an opportunity to spend time in one of our research plots on June 21! Although I could find shot holes in leaves and second and third instars in the whorls, the number of plants infested was quite low. I also observed a third instar in a midrib, so stalk tunneling should be occurring right now.
We gave you the facts on corn borer development, scouting, management worksheet, and suggested insecticides in issue no. 11 (June 14, 1999) of this Bulletin.It's only a brief matter of time before we know, with hindsight, the full extent of our first go with European corn borers. After that, we can start guessing about what the second generation might have in store for us.--Kevin Steffey