Cluster flies are slightly larger than the Common House Fly at about 5/16ths of an inch long (7mm). There are no distinct lines or stripes behind the head, is non-metallic, light in color and the abdomen has irregular light and dark gray areas. These flies appear during late autumn, winter, and early spring at windows and in rooms not frequently used. When crushed, they leave a greasy spot on upholstery, carpets and wood surfaces, an annoyance in itself causing many people to seek cluster fly control.
The female lays eggs in the soil near the burrows of earthworms. Tiny maggots of Cluster Flies hatch from the eggs and seek out the earthworms to feed upon. The maggots are reared solely on living earthworms and when they reach maturity, the parasitic maggot leaves the body of the host and is ready to seek a mate and start the cycle all over again. There are about four generations of Cluster Flies a year.
As cold weather progresses during September into Mid-October, adults seek protected places to spend the winter. In many cases, this is within walls, attics, storage rooms and basements of houses. Screens offer no protection since these flies prefer to crawl in through small openings elsewhere around the building. For this reason they are extremely difficult to keep out of houses. Isolated houses in the country are especially prone to invasion, since they offer the only warm shelter for miles around.
Cluster Fly Removal
Complete Cluster Fly control is almost impossible since the adults become concealed in walls and attics over the winter. It is also not practical to attempt to control the host of Cluster Flies, for earthworms are important to soil, and Cluster Flies would simply come from surrounding areas. What you can do is call Catseye Pest Control to help. We can use a treatment process that is concentrated inside the home where the adults hibernate and around the exterior of the house to prevent transient behavior. Timing is the most important factor with this treatment. Application should be made in the first two weeks of August.
For those adults that are visible in the home during the winter, they are sluggish enough to be picked up with a vacuum cleaner. Also, in preparation for the season when cluster fly control is needed, covering the louver to the attic with a screen and using a caulking compound to seal openings to the outside can help as well.