This article was written by Howard Russell, MSU Diagnostic Services, Department of Plant, Soil and Microbial Sciences
Flies of all kinds peak in numbers during late summer because there is lots of decaying fruit and other organic material out there this time of year. Fall is the time of the year when fruit flies, also known as vinegar flies, can become very bothersome in homes. This is especially true for anyone with a vegetable garden or backyard orchard.
Fruit flies are very small, light brown with red eyes. They love fermenting fruits and are attracted to any sweet liquid be it fruit or vegetable juice, soda and beer left in the bottom of the can, or something thrown into the garbage can. Fruit flies may be small enough to pass through window screens, so it is difficult to keep them out of the house. They are very irritating to gardeners who want to display their hard-earned produced on the kitchen table. If you put a bowl of tomatoes or fruit out this time of year, it will likely have a swarm of these tiny little pests around it in a matter of minutes. Many callers claim they appear out of nowhere.
Eliminating those things that attract fruit flies is the best way to avoid problems. Ripe fruit or damaged fruit should be eaten, refrigerated or thrown away. 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 that none are starting to rot or leak juice. 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.
Adult fruit flies can be controlled with aerosol insecticides labeled for household use. Homemade or commercially available fruit fly traps are also very effective in reducing their numbers. Many trap designs are available on the Internet. Here are two designs Michigan State University Extension recommends that readers have reported to be effective.
- Use a small jar with a homemade paper cone set on top with the narrow end of the cone pointing up. 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. The flies seem to like the wine much better than the juice. Empty the trap and replace the splash of wine every day. (Vinegar will also work as bait; good wine should be drunk, not wasted on fruit flies!)
- Fill several juice glasses or smaller with apple cider vinegar to about two-thirds full. Then 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.
This article was published by Michigan State University Extension. For more information, visithttp://www.msue.msu.edu. To contact an expert in your area, visit http://expert.msue.msu.edu, or call 888-MSUE4MI (888-678-3464).