Seeing one wasp often makes people panic, and anyone who has been stung knows why. When a wasp enters your home, your first thought is to kill it. Using a fogger or bug bomb seems like a great way of doing that. In reality, the fogger will either be too much or not enough to deal with the problem.
Foggers are designed to spread aerosol insecticide around a room. The insecticide typically contains a chemical that keeps it suspended in the air. Although foggers can be effective at killing bugs in hard to reach areas, like attics, they are seldom effective at eliminating indoor pests, according to Michael Potter, an extension entomologist with the University of Kentucky. Plus, they can have a negative effect on your health and be a safety hazard.
Winter and Early Spring Wasps
If you discovered the wasp on a warm day above 70 degrees Fahrenheit in the winter or early spring, then it is a solitary female. Females overwinter in chimneys and wall vents. The rest of the colony dies out once the weather gets cold. When the female emerged, it flew toward the light, which happened to be inside your home rather than out the chimney. These wasps tend to be slower-moving and may even crawl on the floor. Killing it with a fly swatter or insect spray is the easiest method.
Summer and Fall Wasps
If you find a wasp in your fireplace in the summer or fall, then there are two possible causes. One is that a solitary wasp flew down the chimney or into the house and got stuck in the fireplace. In this case, you can kill it with a fly swatter or insect spray. The other possibility is that a wasp colony has built a nest in your chimney. This is a trickier problem to deal with. Rather than sticking your head up the fireplace to check, watch the chimney for wasp activity.
Wasp Colony in a Chimney
Wasps are more likely to build nests in attics and wall voids than chimneys, but it can happen. If you suspect a wasp nest in your chimney, call a professional pest control service. They can determine the best way to eliminate the nest, get it out of your chimney and prevent the problem from happening again. Although the wasps may be paper wasps, they can also be hornets or yellow jackets, which will aggressively defend their nests. Aerosol sprays and foggers are rarely effective when dealing with hidden nests, according to university extension experts Jeffrey Hahn, Phil Pellitteri and Donald Lewis.
- North Carolina Cooperative Extension Service: "Paper Wasp Swarming around Structures"; Stephen Bambara, et al.; January 2008
- University of Minnesota Extension: Wasp and Bee Control
- University of Kentucky: Limitations of Home Insect Foggers (“Bug Bombs”); Michael Potter
- Seattle Post Intelligencer: Bug Bombs Don't Just Kill Pests: People, Pets Also Sickened by Foggers
- Texas A&M University Agrilife Extension: Paper Wasps, Yellowjackets and Solitary Wasps (PDF)
Darcy Logan has been a full-time writer since 2004. Before writing, she worked for several years as an English and special education teacher. Logan published her first book, "The Secret of Success is Not a Secret," and several education workbooks under the name Darcy Andries. She received her Bachelor of Arts in English and Master of Arts in special education from Middle Tennessee State University.