When I opened up a wall in our house this morning for some electrical work I found what looks like a wasp nest. It’s gray and papery and fills most of the bottom half of the void space, about 2 feet long by 1 foot wide. It freaked me out and I quickly closed the wall back up. What do I do now? H. P., Roslindale, MA

That void nest could belong to yellowjackets, or European paper wasps, European hornets, or even honey bees. Each nest is distinctive and an expert could tell the difference. The void nests of paper wasps and European hornets usually consist of open combs without a papery covering. Yellowjacket nests will have a papery gray/brown covering over the combs. Honeybee nests will have layers of open, waxy combs with honey in some cells. From your description, it is most likely that the nest belongs to yellowjackets (see Yellowjackets Do Nest Inside Homes).

Yellowjackets nesting inside walls come and go to the nest through an outside opening on your house. If that opening is hidden by trees or siding, for example, you may never notice the activity. The entrance hole on the outside of the house does not always lead directly into the void nest. Wasps may travel up to 30 feet to reach the nest once they enter the opening.

Last Year’s Nest Will Be Inactive

The good news is that what you found is almost certainly an old, empty nest (note that I said almost certainly). In our part of the country, wasps don’t reuse their nests from year to year; they begin a new nest every spring. If the nest you found was active, you would have seen wasps, or at least heard them angrily buzzing when you opened the void. The action of opening the wall void would have caused enough vibration and disturbance to rile up any wasps in the nest.

If you feel certain that it’s an old nest, while you have access to the void you should remove the nest from the space. The reason is that other insects, particularly dermestid beetles, might move into the nest to feed on any dead larvae or pupae or even on the nest itself.

Get Professional Help For an Active Wasp Nest

You might want to contact an exterminator just to make sure that the nest is unused and for an inspection of the exterior of your home for any new nest activity. Wasps do tend to build new nests in the same general area where they nested last year. At Colonial Pest, we can seal up openings that would allow wasps to enter voids such as gaps around conduits, vents, exhaust fans, or holes in mortar or around window frames.

If you think the nest might be active, that’s something you don’t want to deal with on your own. Always contact a professional who can safely deal with void nest treatment and removal. (see Call an Exterminator to Get Rid of Yellowjackets Nesting in Walls).

Photo Credit : “Wasp nest 2” by Richerman | CC BY-SA 3.0 via Wikimedia Commons.