Japanese beetle adults are just starting to emerge in southwestern Ontario and some have been spotted in Niagara and Hamilton. Look for these shiny green and copper beetles feeding on grapes, roses and other flowers. Where possible, knock adults into a bucket of soapy water (to kill them). Several insecticides are registered for the adults, including Sevin XLR.
European chafer adults starting to emerge. Look for medium brown scarab beetle swarming blooming Linden trees (e.g. Tilia cordata). Historically we see them around Canada day in the Guelph area but this year has been a little kooky with weather.