By Jeffrey Hahn
University of MN Extension Entomologist
---- — Some Minnesota residents have recently been experiencing problems with wasps in their homes.
The first reaction they generally have is that they have an active nest somewhere in their building. However, what people are actually seeing are just queens who have been hibernating since last fall.
The old queen and all the workers die when freezing temperatures arrive in the fall; nothing is left alive in the nests. The only survivors are new queens that are produced at the end of summer. They leave their colonies and look for places to spend the winter. That could be under loose bark, under leaves, in or under logs, or in the cracks and crevices of buildings. Wasp queens usually overwinter individually. However, paper wasp queens tend to overwinter gregariously.
People can rest assured that if they see wasps in their buildings now, even if there are a lot of them, they are not nesting in their homes. The wasps are just overwintering insects that become active with warmer spring weather, like a boxelder bug or a lady beetle.
All the queens will eventually become active and either find their way outside or become trapped indoors. When you find wasps in your home at this time of the year, the best control is to physically remove them as you see them. They are generally sluggish when they first become active so you should be able to dispose of them with less risk of being stung.
To minimize this problem next year, it is important to seal up as many potential entry points around the outside of your home as possible. This can be supplemented with an insecticide treatment around the exterior during late summer or early fall. If this is difficult task for a homeowner, they can hire a pest management professional (pest control operator) to do this job.