Insect pests within homes can be damaging to property or medically threatening, while others only pose a nuisance. Termites and other wood-boring insect pests, like powderpost beetles and carpenter ants, are categorized as economically significant pests due to the costly damage they inflict to structural wood and other finished wood sources within and on the exterior walls of houses. Many other insect pests, like carpet beetles and clothes moths, do not inflict damage to valued wood sources, but their habit of eating away at indoor fabrics makes them economically significant pests as well as a nuisance. Flies, cockroaches and venomous insects pose a medical threat to humans within homes. For example, cockroaches and flies congregate on pathogen-rich organic materials, like excrement and rotting foods. When flies and cockroaches enter homes, they smear food sources and indoor surfaces with these pathogens, making these insect pests a disease threat to humans. However, in some cases, insects that are categorized as nuisance pests may also cause direct or indirect damage to the homes that they infest.

Cluster flies are one of the most commonly encountered insect pests within homes in the northeastern US, but due to their breeding habits, they are not considered to be a significant disease threat; instead, cluster flies are categorized as nuisance pests due to their habit of entering homes in large numbers during the fall in order to secure warm shelter for overwintering. When the temperature drops below 53 degrees, cluster flies enter homes through any entry points they can find on the exterior walls of houses. Once indoors, cluster flies maintain a significant presence within inaccessible locations, such as wall voids, tight attic spaces, and below flooring. In some infestation cases, turning on indoor lights will prompt cluster flies to emerge from their hiding spots, especially when they are located above ceilings near light fixtures. The heat emitted from indoor lights gives cluster flies the impression that warmer spring weather has arrived, which causes the flies to swarm indoors during the winter in an effort to find access outdoors. When cluster fly infestations become extensive, walls sometimes need to be torn out so that insecticide can be delivered to the pests, which is obviously a costly undertaking. In order to avoid this scenario, pest control professionals apply minimal amounts of insecticide to the exterior walls of homes before the fall season arrives. Insecticides like cypermethrin or cyfluthrin are used for this purpose, and they repel cluster flies for months without posing a danger to humans, pets or wildlife.

Have you ever had insect pests establish shelter in the wall voids of your home?