No. 9 Article 3/May 21, 2004

Insects Thus Far in 2004 (and Possible Coming Attractions)

As usual, weather has been the primary focus for corn and soybean producers throughout Illinois--first, really good weather, and now quite a bit of rain in some areas. Weather always has some influence on insects, and this year (thus far, anyway), the weather seems to be favoring us rather than the insects. Are we experiencing calm before the storm, or will insects take a backseat to other issues in field crop production this year? You probably know me well enough to know that I won't (actually can't) answer that question, but the question begs for attention. And the only way we will answer it--in hindsight--is to stay vigilant, even when insect problems seem to be few and far between. A colleague recently observed that "it's no fun scouting for insects when you can't find anything." As an entomologist, I tend to agree, but the shortage of insect pests certainly bodes well for producers.

Throughout the past few weeks, we have received reports of black cutworms, wireworms, and white grubs causing economic damage in a few fields in southern and central Illinois, but their infestations have not been widespread. Southern corn leaf beetles and flea beetles were relatively common in western counties, and a few grape colaspis larvae have been found. But overall, this group of secondary insect pests of corn has caused only localized restlessness.

We have received a handful of reports of observations of armyworm larvae but no reports yet of armyworms causing any problems in Illinois. However, Ron Hines, senior research specialist at the University of Illinois Dixon Springs Agricultural Center, reported that radio broadcasts from southwestern Missouri indicate that armyworms are feeding in wheat and grass hay fields. So keep your eyes on such fields, if only to avoid the surprise we experienced in 2001.

Another insect to watch in the coming weeks is the European corn borer. This insect has been nearly invisible in most areas of Illinois for the past few years; some have speculated that Bt corn has been responsible for the apparent absence. Maybe, maybe not. Regardless, announcements of moth flights should always focus our attention. And as usual, Ron Hines is the first to report the first European corn borer moth flight of the season in Illinois. He recorded capturing 62 European corn borer moths in the trap in Pulaski County during the week ending May 18. His first European corn borer moth capture at that site was during the week ending May 4. A very few moths also have been captured in traps in Massac and St. Clair counties. As you know, early-planted corn is most at risk for infestations of first-generation European corn borers. Growers in southern Illinois should monitor early-planted cornfields soon, watching for evidence of leaf-feeding injury as the larvae establish in the whorls. Tunneling by larger larvae will ensue shortly thereafter.

In soybeans, the insect to focus on right now is the bean leaf beetle. An article in last week's issue of the Bulletin (issue no. 8, May 14, 2004) provided information about their management. The next insect to watch for in soybeans will be soybean aphids (refer to "A Brief Summary of Soybean Aphid News" in this issue of the Bulletin.

So far, so good. But as you know, significant insect problems can develop rather quickly. With many weeks to go before we reach the end of the growing season, our skills of observation, preparation, and reaction still will be tested.--Kevin Steffey

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