We have a problem here. We have sprayed several times with the foamy stuff but they just seem to laugh at it.
I got a good deal (so I thought) on that foam chit a few years back and found out it was pretty much useless! Must be water based...... I have been using the wasp/hornet spray that comes in a black spray can. It works great! I will check the brand later.
If you could rig a shop vac up to the hole that would be a good option. Rig it up at night and turn it on the next day. I’d use a step ladder, duct tape, bungies to hold the nozzle where it needs to go. Probably want to put an inch or so of soapy water in the bottom of the vac. The motor will probably get warm so you may have to turn it on and off through out the day. edit: the motor running will really cheese them off too. That’s a good thing because they’ll come out and get sucked into the vac.
Does it need to be shaken before using? I used some foam for the first time recently and it was 100% effective
At work we had a big nest in a large concrete seam (read: gap) about 10' off the ground, we grabbed a stick of 1/2" PVC conduit, packed part of a paper towel into the end to act as wadding, loaded it up with some sevin dust, packed a wad over the end, placed it up into the seam and blew on the conduit with a blowgun hooked to a portable compressed air tank...end of nest.
Sounds like a redneck power duster. These hand dusters are common but have no horses behind it. That sounds like another good option.
I have one of those powder poofers, I believe it would work. The powder is supposed to stick to their feet and they drag it into the nest.
I do a preventive spray and powder applications every fall. Windows, door corners crack and crevice. The pest is stink bugs. I can tell when they have been through the insecticide. They move their legs, it reminds me of making and fist then opening my hand up all the way. Kinda like what you would do if my hand fell asleep. It’s obviously starting to work. Insects also groom or clean themselves which can fast track the effects of the insecticide. I would make note most pesticides take time and are not an instant silver bullet. They need some time to work. Sevin dust is good, I still have a couple of lbs of delta dust from my pest control days it works great. It’s not something you can buy at the store like sevin. If you do get a hand duster or billow duster don’t go crazy squeezing it hard, we had some tear or break with ham fisted employees. I find they are effective when filled 1/2 way.
I have done similar to what brenndatomu talked about. Fill a section of pvc with an elbow on the bottom. Then blow the sevin into the entrance.
The foaming stuff worked for me with a nest that was in a bush. The entrance hole was accessible. Hit it with the foam in the evening and the nest was inactive the next morning. I'm not sure of it's effectiveness when the nest is in a structure. Good luck!
I've always had luck with brake cleaner. Should be able to blast some in there and by the time they decide to get pizzed off at you, they won't be able to do anything about it.
