The armyworm outbreak of 2001 is still a fairly vivid memory for some people, so captures of armyworm adults in traps this spring deserve some attention. We have always known that armyworm moths fly into Illinois at the same time that black cutworms arrive, but this time we should be more vigilant to watch for their arrival.|
Armyworm adult. (Note the very small, white dot in the center of each forewing.)
Ron Hines, senior research specialist at the Dixon Springs Agricultural Center, has captured a few armyworm moths in his traps in southern Illinois, although the numbers captured this year are far fewer than the numbers captured last year. From April 9 to 16, Ron captured 3, 1, 3, and 11 armyworm moths at the Massac County, Pope County (upland), Pope County (bottomland), and Pulaski County sites, respectively. Lee Townsend, Extension entomologist at the University of Kentucky, reported (April 15, 2002, issue of Kentucky Pest News) some armyworm captures at the UK Research and Education Center in Princeton. He mentioned that the first-week catch this year was 37 moths, compared with 213 moths captured during the comparable time in 2001.
Wheat fields and grass hay fields and pastures will be the focus of our attention for armyworms soon. The females deposit their eggs on the leaves of grass hosts, and the young larvae begin developing after they hatch. We will want to be on the lookout for the small, green larvae and evidence of minor leaf feeding early this year, just so we don't get caught unaware. Although leaf feeding by young instars is not economic, it's a signal to watch for more serious defoliation in the near future.
I'll provide more specific information about armyworms in wheat and grass fields in next week's issue of the Bulletin.--Kevin Steffey