I believe the U of IL had an adult beetle eradication program (spray beans the prior year) continuous trial in an area near us, Bugkiller. I believe it was started about 10 yrs ago and then discontinued 5 yrs ago after being declared a failure. No spring insecticide was utilized. I believe the plot was just SW of Sheldon, IL. Presentations were watched pretty closely in this area. For those not from "here", that plot would be about 45 mis E of Bugkiller. Maybe their CEC to Goss ratio was out of balance though...don't know those numbers.