Cluster Fly – Pollenia rudis

History

Often confused with the common House Fly, Cluster Flies are roughly the same size. However, they fly somewhat slower than the House Fly and usually fly toward windows on the warm side of a structure. When at rest, their wings overlap almost completely.

Cluster Flies breed in the ground outside of buildings during the warm weather (late Spring into early Summer) using earthworms as a food source for the immature larvae (maggots). The flies later pupate (go into the cocoon stage), then hatch as adult flies. In temperate areas, often in late August, these flies begins to migrate indoors finding any small cracks or crevices that permit entry into structures. These may include areas around window frames, door frames or eaves. Entry tends to be on the same, warm, sunny side (often the southern or western exposure) of the structure as the flies later emerge from.

During the Autumn, Winter or Spring months, these flies may emerge, particularly on warm, sunny days. The flies appear at windows buzzing and “clustering” around those areas to the dismay of the occupants. This fly can become a problem in virtually any structure and they have, on occasion, been a problem in sensitive areas such as hospitals, where they are especially unwelcome.

Why Control Cluster Flies ?

Whilst Cluster flies can be a great nuisance they do not normally represent any health risk. However they can :

• produce a rather sickly smell when clustered in large numbers
• be upsetting or unnerving if disturbed during hibernation
• be unsightly

Method of Control

• We control Cluster Flies by treating the adult resting sites and harbourages.
• They may have flown a considerable distance from their original breeding site, so we do not attempt to control their larvae.
• Typically, the treatment will include a spray with an insecticide to affected window frames and the interiors of sash-window cases.
• We will also inspect the roof spaces and, where appropriate and safe to do so, use a smoke generator to eradicate any residing cluster flies.
• Electric Fly Killers, hanging in attics or loft spaces, are particularly effective in providing continuos control.

To find out more about how we can help you on a one-off job basis or with a longer term preventative Service Plan please call us on freephone 0800 0283 703. Alternatively complete our online contact form for a free survey and detailed quotation on how we can eradicate your pest problem.