Wasps sting, they make nests under decks, gutters, eaves, window seals and siding. They are very territorial, meaning infestation is likely. Wasps are active from June to September/October and some species until December. It is a good idea to start preventative treatment around the perimeter of your home beginning the month of March/April and into the summer to prevent nesting. The earlier service is provided the more effective treatments are.