No. 12 Article 3/June 11, 2004

First Captures of Japanese Beetles in Illinois in 2004

Ron Hines, senior research specialist at the University of Illinois Dixon Springs Agricultural Center, activated his Japanese beetle traps in late May, and he already has captured Japanese beetles at a couple of locations--Pope and Pulaski counties (6 and 5 beetles captured, respectively)--during the week ending June 8. As Ron indicates in his comments in "The Hines Report", these captures in 2004 are at least two weeks earlier than the first captures in 2003 and 2002.

Japanese beetle trap at the University of Illinois Dixon Springs Agricultural Center (photo provided by Ron Hines).

Japanese beetles captured in a trap in 2002 at the University of Illinois Dixon Springs Agricultural Center (photo provided by Ron Hines).

This report of early emergence of Japanese beetles should place people on alert throughout Illinois. During the next few weeks, Japanese beetles will begin emerging throughout the state, so everyone will have to keep their eyes peeled for insect movement into corn and soybean fields. As we have learned, Japanese beetles tend to fly into cornfields when pollination is under way, and their silk-clipping behavior threatens ear fill. This type of infestation is particularly troublesome in seed-corn fields.

To add a little more information to this alert, Kevin Black with Growmark, Inc., in Bloomington has reported that densities of Japanese beetle grubs in representative fields have been high this year. Although we have received fewer reports of grub injury in 2004 than in the previous few years, injury in some fields was significant. We also know that the grubs tend to cause more damage when soils are dry, a situation we have not encountered much this year. But as Kevin indicated in his report, the large densities of grubs in some areas portend significant numbers of adults.

Japanese beetles feeding on an ear tip in southern Illinois in 2002 (photo provided by Robert Bellm).

At this point, no one really knows how widespread Japanese beetles will be in Illinois in 2004, but their emergence in June bears watching everywhere. People in areas where Japanese beetles typically occur are already poised for their reappearance. However, I encourage people in "new areas" for Japanese beetles to be vigilant, too. The worst infestations of Japanese beetles often occur in areas where they weren't expected. We will provide management recommendations in a future issue of the Bulletin. --Kevin Steffey

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