Cluster Fly Pheromone

Asked November 13, 2017, 3:59 PM EST

Hello there. I've communicated with your team in the past about cluster flies. They are a real problem at our home. We've done our best to seal windows, etc. in order to keep them out. I recently learned that they may emit a pheromone that leads other cluster flies to follow them to the "safety" of our home. If we wanted to eliminate the possible pheromone how would we do that? What type of cleaner or odor eliminator could we possibly use to neutralize it? Thank you, David Wrenshall, MN

Carlton County Minnesota insect issues cluster flies

1 Response

Thank you for the question. I was unable to find information on cluster flies and pheromones so passed your question along to University of Minnesota Extension Entomologist Jeff Hahn. Here is his response:

"I could not find any information in my literature that suggests that there is pheromone that cluster flies release. Cluster flies are very attracted to the sunny sides of a building; this is what draws them to a given building. Once they have entered cracks and spaces, they then crawl inside as far back as they can. Even if a pheromone is used, it would not change what needs to be done which is to prevent the cluster flies from entering buildings to begin with.

The homeowners mention sealing entry points which is definitely part of cluster fly control. However, it is not possible to completely make a house insect-proof. Exclusion needs to be supplemented by well timed and placed insecticides. It is too late to treat now; insecticides should be applied during late summer and early fall as cluster flies start to move towards homes. They also do not mention whether they have ever used a pest control company. If they are suffering through such chronic problems, they may want to consider using a professional to help them."

I hope this information is helpful.