Cluster flies can be an incredibly frustrating nuisance, not to mention potential health threats.
Cluster flies are slow moving insects that usually hibernate during the winter months in wall voids or attics before emerging again in spring to seek warmer places for shelter.
Mechanical Exclusion
Cluster flies (Pollenia rudis) are large black flies found in homes from late fall through early spring. Although genetically related to bottle or blow flies, cluster flies do not bite humans like their relatives do.
Cluster flies tend to look for shelter from the elements during autumn. Their ideal overwintering sites tend to be light colored structures with warm south- and west-facing walls.
Once inside, these pests tend to congregate in dark and inaccessible spots like wall voids and attics – making it hard for homeowners to locate and treat these unwanted guests on their own. It may require professional assistance in order to effectively locate and treat these vermin.
If pests have already established themselves within your home, professional pest management professionals will seal off all cracks or crevices that allow them to enter, apply preventative treatments with 30-day or longer-acting residual insecticide to exterior walls, as well as space treatments in wall voids or areas where flies congregate.
Aerosol Sprays
Cluster flies, as their name implies, congregate in large swarms of thousands of insects that tend to appear during late fall and early spring when temperatures have become cool enough for them to seek shelter inside homes and buildings.
Exclusion techniques can help keep cluster flies at bay. These include sealing gaps around exterior vents, rooflines, water spigots and pipe entry points as well as foundation sill plates to seal them off from entering your home.
When cluster flies invade your home, spray with aerosol sprays containing pyrethrum to eliminate them quickly and safely. Pyrethrum is nontoxic to people, pets and fish but may be toxic to other insects.
Indoor treatment involves spraying with contact pyrethrum aerosol sprays such as CB-80 and PT 565 for immediate insect knockdown. You can spray these on door frames, baseboards or nearby window trim to eliminate flies quickly.
Contact Sprays
If you’re experiencing cluster fly issues in your home, contact sprays can be an effective solution to killing off those already inside. An insect spray containing pyrethrins will kill off these insects instantly.
Check your house for any gaps where flies might be entering and use a residual insecticide such as Cyzmic CS, Bifen IT or Cyper WSP to spray. Furthermore, spray any windows and doors outside with water to saturate their exterior surfaces while sealing any small cracks with caulk to further inhibit their entry.
Cracked baseboards, window and door frames and exhaust fans provide entryway for flies into your home. Insects may also enter through vents and molding that heat up during spring and fall when they search for heat sources.
Traps
Cluster flies can be a formidable pest to eradicate. They enter houses in large numbers and often gather around weatherproofed windows during autumn, winter, and spring months.
As temperatures cool off, people seek refuge in wall voids and attics – typically found on the south and west sides of buildings in upper two or three stories.
Proofing these areas and keeping food and water away is of utmost importance, with cracks and crevices sealed shut and food sealed up in containers or cans being an effective means.
As well as these methods, another effective solution for cluster fly infestation is using sprays containing pyrethrins to quickly eliminate them. However, this should only be used as a last resort as these toxic substances are harmful to both people and animals alike. It is advised that an exterminator perform the treatment if you do opt to go down this route.