Find the entry hole. Wait until deep dark on a cool evening -- early morning dark is even better. Wear heavy clothing, including hat with face netting (can be scrounged together out of bits and pieces of old sheer curtains, etc.). Can of wasp bomb in one hand, flashlight in the other. Locate hole. Spray. Run like he!! .
Wait a day and observe to see if a repeat treatment is necessary to knock down the strays. Remove that bale very cautiously and dispose of accordingly.
Yellow jackets around here make large nests under ground - like in an old rabbit hole, or decomposing stump, always low to the ground. You can fog them early in the morning and close up the nest, tear out the nest and they will fly away over the course of a day. You may get a professional to come fog and eradicate them.
Armadillos dig up and eat the eggs too so it's not unusual to come across a mad den of wasps trail riding early in the morning after armadillos have had a midnight snack.
Good luck but I think you may want to get a professional because there is no telling how large the nest is until you've uncovered and/or opened it and by then it is too late. They do go dormant in cool temps (like the 50s), if you want to wait till a cool fall morning?
Yellow jackets are nasty buggers! The hispanics I know call them "picantes" like in hot sauce - and yes, when they sting it does burn something fierce.
Unknown to us, some built a nest inside our tractor and I discovered it as I was mowing the back pasture. I'm sure I would have been an hilarious site as I swatted and dodged and shrieked as I was trying to get off that tractor!
We had a bumble bee nest in a bale in the mow. I knew it was there. My husband knew it was there. We kept gradually using up the surrounding bales with the intention the my husband would do them in some dark night. Then my mother found the nest. "Do you know you have a bees nest in a bale in the barn?" Me-"Yes, leave it alone and DH will take care of it." About 45 minuets here Mother comes flying out of the barn with angry bumble bees in her wake! She sprayed a can of Off all over her and in the air around her thinking they would leave her alone while she drug the bale out of the barn. She's my mother, why should she believe me when I said leave the bees ALONE?!?! Mothers are supposed to know more than their daughters, right?? Since she is not alegeric and didn't get really hurt, I did get a pretty good chuckle out it.
Here's an age old solution that while stinky, works like a charm.
Find roughly where they are. Get a dead fish. Shove a rod through this dead fish. Suspend the now very dead, skewered fish over a 5 gallon pail that has about 1/3 filled with water and detergent.
Leave the pail ( with your soon to be very stinky dead fish) in front of their hangout place.
The little buggers will swarm out and feed on the fish...and gorge. One sated, they drop off and fall into the detergent solution, which slimes them up and kills them.
We destroyed a large nest that was in the foundation of our garage in 2 days using this method. It works, but boy! It reeks!
We've had them in our hay feeders - in the little round drain holes. Ba$tards would swarm and sting you as you cleaned them out or re-filled them and the horses were afraid to go near them - great - hay feeders that my horses are afraid to use!
I did "seem" to get rid of them last year and this year - *touch wood* - have only been stung once and have only seen one wasp come out of one, so they seem to have moved on
Friend of mine had her wasps take up residence in their phantom - she had one HELLUVA time getting rid of them from there and after being stung a couple of times until they figured out what was happening, her stallion wanted no part of that "thing" that bit him every time he got near it! So great - a stallion that didnt want to use the phantom for fear of getting stung!
And thank God for cabs on tractors that are totally airtight ... I was moving a big mound of dirt from in front of our barn and I guess the buggers had built a ground nest in there. As I was digging, there were thousands and I mean literally THOUSANDS of pissed off yellow jackets swarming the tractor and stinging the bucket, the windows - you name it. I kept a wary eye on the little air vents (thank God for air conditioned cabs as well!) thinking any second dozens would be coming through to get me and not one single one made it through. Sure explained why we had such a bad wasp problem around the barn that year though ... From what I could tell, the ground nest was about the size of a basketball - flipping huge!!!
TrueColours - what an experience! I'm glad you were ok and no animals around to get stung!
I think that's why armadillos are the only ones who will dig them up on cool nights, they have armor if any wasps are awake enough to sting them. They usually only do it in the Spring and Fall when it's cool at night. Of couse those mornings are the best for a trail ride and it's no fun to get attacked by yellow jackets, but good horses won't buck you off while you run a bit to get away from them.
Those nests can be huge and connect to a sister nests underground.
Remember bees and wasps in a swarm will go for carbon dioxide air - your breath - so cover you mouth, nose, and neck with your tshirt and run like heck! Don't try to hide, unless in a car, truck, or other totally enclosed area.