Yellow jackets, especially German yellow jackets, typically build their nests in the ground or in logs or tree stumps, but sometimes they can nest in the wall, ceiling or attic of a home. The nest could be the size of a basketball or bigger. The nest will be active for only one summer. In the fall the queen yellow jacket will fly away to start another colony. The remaining yellow jackets will die off, and the nest will not be reused. If the yellow jackets are nesting in your home, however, one summer will probably be too long to have them as guests. You will want to get rid of them.
Find the nest. You can do this by finding the entrance hole and then tracking it to the nest, which could be up to 30 feet away. The entrance hole could be a chink in outside mortar, open space around a window frame or an opening in a conduit, vent or exhaust fan. Alternatively, find the nest by placing your ear or a glass against the wall, and listen for activity on the inside part of your wall.
If you cannot find the precise location of the nest, spray a pyrethrin-containing aerosol in the entrance hole. Make sure the product will not leak into your home through electrical outlets, vents or holes. This will eliminate yellow jackets near the entrance hole. But if the nest is too far away, the aerosol may not reach it.
When the aerosol is dry, about 10 to 15 minutes later, inject the entrance with pyrethrin dust. The dust will kill off the yellow jackets in the entrance and drift back to the nest, if it is not too far away. Leave the entrance hole open for a few days so the insecticide can eliminate any returning yellow jackets.
If you have found the precise location of the nest, drill a hole into the wall at the site and inject the aerosol and dust into the nest. Seal the drill hole.
Decide if you will remove the nest or not after treatment. The cost and the necessity of removing it will depend on the location. If the nest has a considerable amount of dead larvae, it could rot and attract other insects.
If you decide not to remove the empty nest, inject a long-lasting repellent insecticide. This will kill off any residual yellow jackets or other insects that may nest. Seal off the entrance hole to prevent any other queen bee from nesting there in the future.