If they aren't acting aggressively like defending a nest and aren't particularly bothering you, why don't you just give it a couple of days and see what happens.

I wonder if they are being attracted to water - if you are irrigating your lawn, or hunting some kind of insect present there. I've watched yellow jackets hunting crane fly larvae in my lawn when those begin to hatch, so a beneficial behavior rather than something to treat.

I don't think I've seen anything in quite the numbers you describe though...let us know what happens.

morz - they aren't acting aggressively, and I'm mostly fine with just letting them be. The urgency is past (wife was hosting a bridal shower with seating/dining on the lawn yesterday). I too am assuming they're hunting for something.

Nothing has changed w/ watering, so I've ruled that out.

Now, if they'd eat the darn spiders that seem to have taken over my property, I'd throw the welcome mat out for them.

I am having trouble with spiders as well. I am going to buy Bombs today and set them off in my attic. That is the only thing that seems to work.

Our spider issues are mostly outdoors, with webs EVERYWHERE. Eaves, stairs, deck rails, tool shed, potting bench, etc. May be time to call Clark, as while I'm all for keeping the buggers around, the webs are just driving me crazy.

Re: the wasps, I think it's a widespread thing in our area right now. Was at a friend's place yesterday, and he had the exact same issue going on with the wasps (covering his yard). Guessing time will take care of it.

Wasp usually hover for 2 main reasons. 1 if you have moisture on the soil, wasp will use it to build their nest. 2 if you have not used any insect repellent on your lawn then they are feeding on the insects. How to control them? water The lawn early morning and or evening and use something like seven lawn care and that should take care of your swap problem