Common Name: Cluster Fly Scientific name: Pollenia rudis Size 8mm
Biology: Eggs are laid in soil cracks and wall cavities these will hatch in about 3 days. Development time from egg to adult varies
from 27-39 days. There are usually about 4 generations per year. Complete Metamorphosis
Habits: As the days shorten and the weather cools cluster flies enter buildings to over winter and can travel more than a mile to
do so. They usually occupy attics and wall voids. They normally use the same structure year after year. They can be a problem
in the autumn and springtime, in the autumn they enter to hibernate. On warm sunny autumn days and again in the spring they
can also be a nuisance when they begin to leave the structures. Once stimulated cluster flies seek UV light. They can be found
crawling around windows or around lamps and lights in vast numbers.
Treatment: Cluster flies when active within a loft space are treated with an insecticidal fogging machine. The machine breaks
the insecticide down into miniscule particles filling the entire loft with a heavy fog of insecticide. This will kill off all active flies on
contact then once the insecticide has dried it has a residual life of up to 2-3 weeks which will kill any newly hatched flies that land
in the treated areas. The treatment may need to be carried out twice a year for heavily infested properties.
