David,
Anna
2

I will have a more substantive reply in a day or so, but I wanted to make sure I got back to you.

In your area there are three groups of social stinging wasps, as well as one group not so social but found in large enough numbers to be a problem near dwellings. Most common pretty much everywhere are the paper wasps. They will have flat, honeycomb-like nest up under eves, in sheds, on porches, in the hollow rungs of aluminum ladders; anywhere that is protected from the rain. Small early nests might only have a few cells and one queen protecting/feeding them. By this time of year nests can have several ranks of cells and be staffed by multiple males and females. Some will be so large that they may have more than one queen.

The only safe way to deal with them (if they are in a place where you commonly go, or near a place where there may be a lot of vibration — near a stair, or close to where powered yard equipment is used) is to use a high pressure distance spray -it’s usually around 4–5 dollars a can, and one can will kill the wasps in a large nest. If you’re brave, a pressure washer will remove them quickly, and can be done at night fairly safely, especially if there’s someone else to hold a flashlight. With either method there will probably be a sting or two. Benadryl (diphenhydramine) will help with symptoms, topically or taken by mouth. If you think you might have an allergy, take the Benadryl first.

I will post more later. One note: I am, in general, against using poison sprays of any kind, but if you have a serious situation involving many stings at all, it may be the best course. More advice tomorrow, about paper wasps, their cousins the yellow jackets and hornets, and their more distant cousins, the mud daubers.