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Will 2001 Be the Year of Lepidoptera?

May 25, 2001
Thus far in 2001, we have experienced a major outbreak of the so-call true armyworm (Pseudaletia unipuncta) and a more recent and less widespread outbreak of variegated cutworms (Peridroma saucia). Both of these situations are discussed in more detail in other articles in this issue of the Bulletin. We have had more than a fair share of reports of problems with black cutworms (Agrotis ipsilon) this year. In addition, Matt Montgomery, Extension unit educator in Springfield, and some of his colleagues have found some yellowstriped armyworms (Spodoptera ornithogalli) in a few fields. And to top this off, people are finding moths everywherein their yards, around crop fields, in traps, and on windshields.

Although we may never know all of the reasons for the success of moth pests to date this year, it's obvious that conditions have been conducive for survival and development of these Lepidoptera, the insect order that includes moths and butterflies. Adult armyworms, black cutworms, variegated cutworms, and yellowstriped armyworms do not overwinter, for the most part, in Illinois; rather, they fly into our state on prevailing winds and weather fronts during the spring. Obviously the moths found conditions suitable for egg laying after they arrived. And their progeny, the larvae causing all of the damage, have found conditions to be to their liking.

So what's next? Observers already have found European corn borer (Ostrinia nubilalis) adults in traps throughout most of the state, and people are beginning to report that they have seen quite a few moths in "action sites," the grassy, weedy areas around crop fields. Although the first reports of whorl-feeding injury have not been submitted, injury caused by first-generation European corn borers will occur soon. Ron Hines, senior research specialist at the Dixon Springs Agricultural Center, reported his first capture of adult southwestern corn borers (Diatraea grandiosella) in traps on May 18, 2001. And he continues to capture black cutworm adults. Captures of corn earworm (Heli-coverpa zea) and fall armyworm (Spodoptera frugiperda) adults will occur soon. And we're not even done with "true" armyworms yetthe larvae continue to cause serious concern, and adults are still prevalent.

Among all the other concerns about growing crops in Illinois, we need to pay particular attention to lepidopteran pests this year. Given our experiences thus far, we should keep our guard up for other caterpillar assaults.--Kevin Steffey

Author: Kevin Steffey

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

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