I have yellow jackets. If they have gone into the walls, will I have a problem? Will the cold temperature kill them, or will they hibernate until spring? Do I need to worry if the nest is inside the wall?
Some reproductive yellow jackets may survive inside the walls. They will come out in the spring looking to go outside. The reproductive yellow jackets rarely sting, so I wouldn't be concerned about it. If the nest is in a very warm location, however, the nest could survive the winter.
I would spray a pyrethrum can of CB 80 or PT 565 directly into the entrance. Do this after dark. They are not as aggressive at that time.
Nests should be located during the day, so you can see the workers entering and exiting all day. Mark the entry points. Treat at night only when it is dark.
Any treatments should be done at night, because they are all in the nest. They don't see well at night and your chances of being stung are greatly reduced.
Pyrethrum forms a gas which will fill the cavity, killing the yellow jackets.
It may be necessary to repeat treatment.
Wait unil the aerosol is dry then dust in the opening withor Delta Dust .
These dusts will leave a residue to continue to kill for months and eliminate any hatch outs Delta Dust is slower acting.
With a little care and caution, yellow jackets can be easily and safely eliminated.
Delta Dust(1 week-slower kill with pyrethrin aerosol