The telephones have been relatively silent, and the Internet wires are pretty cool right now, at least as they relate to European corn borers. We are aware of only a few instances where corn borers might pose a threat that will require action. Andrew Larson, a science instructor at Black Hawk College East Campus in Kewanee (Henry County) followed up on a previous report of a field with 30% infestation and 2.3 larvae per plant in Knox County. He visited several fields in the Galvan and Altona areas (Henry and Knox counties) and reported that some had near-threshold infestations of first-generation European corn borers. He has been watching the development of this generation carefully and observed a significant egg hatch on June 19 and 20.|
In southern Illinois, European corn borers have been very hard to find. Ron Hines, senior research specialist at the Dixon Springs Agricultural Center, has captured very low numbers of European corn borer moths in his battery of traps at four sites in Massac, Pope, and Pulaski counties this year. On the other hand, his captures of southwestern corn borers have been significant. Although most entomologists believe that first-generation southwestern corn borers cause little economic damage, noting their presence is warranted in anticipation of the potentially very destructive second generation. Ron indicated that fourth- and probably fifth-instar southwestern corn borers can be found in cornstalks right now. The flight of moths that will lay eggs for the second generation is just around the corner.
Maintain a vigil for both species of corn borers and let us know what you observe. We've skated through the first summer month with little impact from either one, but favorable environmental conditions could tip the scales in the borers' favor.--Kevin Steffey and Mike Gray