Fruit flies are the small, gnatlike nuisances that buzz around the fruit bowl. They belong to the family of insects called Drosophilidae. Once they are spotted in your kitchen, a sense of doom may set in. "Unless breeding sites are cleaned or removed, the problem will continue," says Dr. Linda Mason, professor of food pest management at Purdue University. Here is her recommended plan of attack.
• Find where the flies are breeding. "They only need a bit of moisture and organic matter to develop," says Mason. While it's true they're especially attracted to ripening fruits and vegetables, they will also breed in drains, the garbage disposal, recycling bins, the trash, the compost bucket, and even mops, sponges, and any other spots where water is caught or leaking.
• If the suspected breeding ground is hard to inspect, like a drain, tape a clear plastic bag over it and leave it overnight. "If flies are breeding there, the adults will emerge and be caught in the bag," she says.
• Remove any potential breeding sites such as rotting fruit entirely. Clean out sites such as a recycling bin with soapy water.
• If the flies are in your drain, clean with a stiff brush, then pour boiling water down along the sides of the drain to kill the eggs. Follow with a bacterial drain cleaner.
• Finally, set up a simple trap to catch the adult flies. Roll a sheet of paper into a cone and put it in a jar with a little apple cider vinegar at the bottom to attract the flies. Once they're in, they won't be able to get out. Even better, says Barb Ogg of the University of Nebraska–Lincoln Lancaster County Extension, is baiting a trap with yeast, a little sugar, and water, because the flies are attracted to the carbon dioxide that is produced during fermentation. A dish filled with soapy alcohol will also do the trick. Mason says not to bother spraying insecticide around, since "eliminating the source and trapping is probably more effective, safer, and less work."
The best bet is to keep the pests out of the house in the first place. Mason suggests being sure windows have 16-mesh screens, particularly if you have fruit trees, as well as cutting any damaged spots out of fruit and vegetables you bring into your kitchen and tossing them outside, as they might be harboring eggs. Finally, try to keep the kitchen particularly clean during late summer and early fall when it's prime fruit season. "A single rotting piece of fruit or spill in a recycling bin can breed thousands of fruit flies," says Mason.