Have any of you found a product that yellow jackets will carry down into their underground lair which will poison the entire hive - much like ant bait? These are between a concrete foundation and block porch so anything flammable is out of the question. Anything that I spray at them just ticks them off and after the initial kill off they are livid. I tossed a shovelful of morter mix onto the hole and then sprayed it with water a good while after dark. By mid morning they had tunneled around it. Tenacious little buzzers! I more than a little concerned for the grandkids who, in spite of warnings and observation, could wander into them.
As always, TIA! Chuck