Place protective screens in attic and chimney openings.
Dust attic for flies.
Follow these specific steps to get rid of cluster flies.
A diazinon spray or dust may also be used for longer residual action.
Say no to gaps.
Spray insecticide where cluster flies hibernating.
Then once the relentless heat zaps the pesticides strength life goes right back to normal for the pest no worse for the wear.
Place dust in cracks and crevices.
Use a fly light.
Attic flies which are also known as cluster flies are insects that often migrate into homes in the fall where they hibernate for the cooler fall and winter months one of the best tips for getting rid of attic flies is to keep them from entering the house in the first place as trying to eliminate them after they are in hibernation can be difficult.
No fog dust or spray in the world will get to anything there.
To be for sure successful attic treatments are still a challenge for pro or diy alike even with some of the best equipment.
Remember attic flies want to cluster indoors when it starts to get a lot cooler outdoors.
Identify where they are.
Spray as best you can around your roof chimney eves ventilation holes etc.
Do not apply too much dust at once or the dust will not be effective as cluster flies will avoid piles of dust.
1 2 puffs at a time will be plenty.
Inject diazinon or bendiocarb dust into window pulley openings and wherever possible into wall voids and other confined spaces where the flies may be hibernating.
Seal up all cracks and crevice and any holes.
To kill the flies that buzz about rooms use a synergized pyrethrins spray or aerosol.