Published on February 5th, 2016 | by Henri


House haunted by cluster flies

Q.  We’ve lived in our house 22 years. When we purchased it, it was 60 years old. What can I do about cluster flies? We’ve had new windows, new siding and a new roof put on, but they still haunt us. Every fall and winter, they drive us crazy. We’ve had exterminators to no avail. We’ve set off insect repellent bombs but they still get in. We’ve put cotton balls with insect repellent on the window sills with no success.

A.    Obviously, the new work you had done did not seal all the little cracks and crevices these flies get through to come and winter over in your house. The best control is to seal all the cracks and crevices on the outside of the house. It’s too bad it was not attended to at the time of construction of the improvements. But let’s keep in mind that it may be very difficult to accomplish in an old house.

To discourage the flies from nesting in the walls, a residual spray can be applied on all exterior parts of the house, especially on the south, east and west sides. It should be applied thoroughly but not to the point where the spray runs off, as a light covering is sufficient.

The time to spray is late August or early September in the colder regions, later in warmer climates, before the first hard frosts when the flies are congregating on the walls. Repeat as needed. You should be able to get the appropriate spray for cluster flies in hardware stores. But if you can’t find it, call the extension service of your university or the agricultural department of your state for sources. Get the concentrate form and follow directions.

If you suspect that the flies are coming in around the windows, readers have told me that they have had success with placing orange peels between primary windows and storm windows. On warmer and sunny days, the flies come out of their hiding places within the house to buzz on windows and light fixtures. Other readers have hung flypaper near windows to trap them. A vacuum cleaner is also useful to suck them all up when they cluster (as their name indicates) on windowpanes.

Of course, you can have a local, independent pest management professional (PMP) do the spraying for you; he or she can also deal with inside infestations. Since the exterminator you used had no success, maybe you need to find another PMP for next year.

Facebookredditlinkedinmailby feather


About the Author

Comments are closed.

Back to Top ↑