Cluster Flies

Cluster flies overwinter in hidden areas of homes, such as in wall voids and attics. Their dropping may leave stains on walls, around window frames and on blinds and curtains. In the spring, the sluggish cluster flies will migrate from their overwintering areas to living spaces and gather on windows as they are attracted to light. Cluster Flies are very annoying as the constant buzzing and vacuuming of dead flies can take place for months.

Cluster Flies

cluster fly

Size: 8-10 mm long.

Colour: They are dark grey with black and silver checkered abdomens, their wings overlap when they are at rest

Description: Cluster flies frequently overwinter in the walls of buildings and homes throughout Canada.  The treatment for cluster flies is very time sensitive, effective treatments must be performed in the spring and fall.

Cluster flies live primarily outside during the spring and summer months.  In late summer / early fall they look to gain entry into our homes and buildings to overwinter for the winter.

The life cycle of the cluster fly is somewhat interesting; in the spring the female cluster fly lays eggs in the soil, often in entry points to earthworm burrows.  The eggs hatch in about 3-7 days and the larvae hatch and search for the earthworm. Once the larvae have found the worm they enter into the worm and develop within it requiring 27-39 days. They leave the earthworm and pupate and the adult fly emerges and the cycle continues.

Cluster flies do not pose any risk to people or pets.  They are a source of great aggravation for those homes unfortunate enough to become infested.  From late fall through the winter and into early spring some houses will experience a constant trickle of cluster flies.  These flies will be attracted to the windows where they will make plenty of noise buzzing around until they die and await the vacuum.  Some houses will experience this year after year

Cannon Pest Control can provide an interior and exterior residual pesticide application to reduce the cluster fly activity inside your home.  This treatment is performed in the early spring when the flies attempt to leave the home and again in the fall when the cluster flies are entering the home.