Bug spray did this to my petunias now what?

Whenbever you hit a delication bloom with a spray or even direct water, the bloom will die. Fresh blooms cannot handle direct ontact witha spray or water. Your best bet is to deadhead (cut off) all the blooms that have been affected even if it means removing entire branches. Petunias are hardy and they will bounce back but it may take awhile depending on how much damage has to be removed. The best method for removing J. beetles is to take a bowl of soapy water and just knock the beetles off into the soapy water. They die almost immediately.