Fruit flies can reproduce anywhere there is wet, fermenting organic matter present. Check drawers and other areas where fruit, potatoes or onions are stored to make sure none are starting to rot or leak juice. For severe outbreak of fruit flies, empty the kitchen garbage can every evening and make sure it is clean and dry before adding new garbage. Any spilled fruit juice, beer, wine or liquids that may ferment should be completely cleaned up. Check under your refrigerator and other movable appliances and furniture for hidden spills and messes. Thoroughly clean recyclable cans and bottles before storing them and avoid storing them in the living space whenever possible.

Fruit flies may also develop in garbage disposals and drains. Drains and traps should be cleaned as well as possible and sterilized with boiling water. If unsure whether drains are the source of fruit flies, cover the drain overnight with a plastic food storage bag and inspect the next morning for adult fruit flies.

In combination with the sanitation steps previously outlined, homemade or commercially available fruit fly traps can aid in reducing their numbers. Here are two fruit fly trap designs Michigan State University Extension recommends:

Option 1. Use a small jar with a homemade paper cone set on top with the narrow end of the cone pointing down (Photo 2). Place a bit of juice or rotting fruit in the bottom to attract the flies. The paper cone will keep them in the jar until they die. A variation of this trap is to use a small kitchen funnel set into a tall wine glass with a splash of wine in the bottom of the glass. Empty the trap and replace the juice, fruit or wine every day.

Option 2. Fill several small juice glasses or bowls with apple cider vinegar to about two-thirds full. Add a drop or two, no more, of liquid dishwashing soap to the vinegar and swirl it a bit. Then, stretch plastic wrap across the top of the glass so it is taut. A rubber band will hold it in place. Punch about a dozen or so holes in the plastic wrap with a toothpick and set out the traps where the flies seem to congregate. The flies enter the trap through the holes and drown themselves in the vinegar. Empty and refresh as needed.