Q. We moved into our house two years ago and we have had an ongoing problem with little black flies in the window sills. I am wondering if the builder could have neglected to seal something in the attic or if you have any idea what I can do.
A. Some areas in the home are more prone to flies than others and flies tend to lay their larva in damp areas such as window sashes. The key to controlling these little black flies is to locate and eliminate their breeding sources. Store fruit and vegetable in the fridge; clean spills on cupboards and near garbage cans. Clean garbage disposal and drains in the sink regularly and inspect your houseplants.
Make a fruit fly trap filling a small dish with 1/2" cider vinegar and 2 drops of dish soap. A second option is to place ½” of red wine in a saucer.
Every spring and fall make a habit of cleaning in and around window sashes. Consider installing a fly screen in your bathroom exhaust fan grille and install a cover on your dryer vent that has a flap on it that remains closed when not in use.