CLUSTER FLIES

Are you fed up with swarms of flies taking over your house and cottage year after year?  Get rid of them now with our Cluster Fly Management Program!

 

Cluster flies are common throughout Ontario.  The flies enter houses and other buildings starting in early September looking for a place to overwinter. Their name is derived from their habit of clustering on outside walls and windows on sunny days. Once inside, they congregate in attics and voids such as walls, cathedral ceilings, etc. Cluster flies are a perennial pest of rural homes, farms, cottages and barns.

The cluster fly develops as a parasite in earthworms.  They do not appear as a result of farm operations, manure piles or garbage.  Cluster flies are more numerous in rural homes because of the large areas that support a certain species of earthworm.  

The adults leave the lawns, gardens and fields in September to fly to protected areas such as buildings, fence posts, debris and stones.  Winter mortality is very high.  In April and May, they return to the field and garden to lay eggs in cracks in the soil.  On hatching, the larvae penetrate earthworms.  They develop through the larval and pupal stage to the adults.  There are several generations of cluster flies in a season.