Issue 6, May 29, 2012
Japanese beetle adults have emerged in Kentucky, so be watchful for emergence in southern Illinois. We continue to see insect emergence about two weeks ahead of schedule throughout Illinois. With emergence in southern Illinois typically occurring around the middle of June, emergence is likely around the end of May.
Japanese beetle adults are present for about six weeks and fly to new hosts every three days. They are strongly attracted to previously attacked foliage, particularly that damaged by Japanese beetles. Season-long control involves at least three insecticide spray applications. If only one application is applied, it should be applied at early emergence to reduce overall damage.
Japanese beetle adults on grape leaf.
Carbaryl (Sevin) and various labeled pyrethroids including cyfluthrin (Tempo) and permethrin (Astro) are effective, with each spray lasting about two weeks. Systemic insecticides such as imidacloprid (Merit, others) will provide control. Hand-picking in late afternoon and evening is also effective. Disturbed beetles will drop into a jar held under them. Add a couple of inches of rubbing alcohol or soapy water to the jar to kill captured beetles. (Phil Nixon)