Cooperative
Extension
Service


University of Illinois
at
Urbana-Champaign


No. 25/December 5, 1997

Corn Borer Densities, 1987 to 1996

Within in the past few weeks, many folks have asked us about the densities of European corn borer populations obtained from our annual fall surveys. As you know, we discontinued our annual survey this year for reasons expressed in a previous issue of this Bulletin. However, you might be interested in seeing corn borer densities during the past 10 years (Table 2). Years ago, we published a bar graph of corn borer densities from the first survey in 1943 through 1990, but we haven't updated the graph. Hopefully Table 2 will help folks trying to document corn borer densities in Illinois. Remember, the densities represent statewide averages from densities in nine crop-reporting districts. Regional densities may differ significantly from statewide densities in any given year.

Table 1. Results from fall surveys of European corn borer larvae, Illinois, 1987 to 1996.


Year% plants infested Avg. no. larvae per stalk
1987781.55
1988310.52
1989783.48
1990601.24
1991913.30
1992310.30
1993501.10
1994490.60
1995651.30
1996641.36

Kevin Steffey and Mike Gray, Extension Entomology, (217)333-6652