Wasps or Yellow Jacket (can't tell the difference by sight, other than unlike bees, they can each sting multiple times) have invaded my backyard under a rock this summer and three cans of wasp insectide later, I think they are now officially dead. Meanwhile, my dog, who has been their main target for attack, will NOT go out anymore, unless forced too, and that is becoming a problem... he is totally traumatized. Don't laugh... it is a sad sight.
They are pretty darn resilient - and whatever anyone intends to do, I would do it after dark, once they are all in and dormant, and shy away from gasoline, as it is a climbing area afterall...
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Mim