Q. How do you get rid of those tiny, little flies that come with some produce and seem to multiply before your eyes?
A. The little flies that frequently appear near unrefrigerated produce in your kitchen are probably fruit flies, which are sometimes called vinegar flies. They are extremely hard to get rid of, but if you use a multiphase plan of attack, you should be able to do it.
Fruit flies can lay up to 500 eggs at a time near the surface of fermenting (ripening) foods or other organic materials. The entire life cycle from egg to adult takes only about eight to ten days so they proliferate with great rapidity. They can also lay their eggs in sink drains, garbage disposals, empty bottles and cans, garbage bags, and even damp mops and sponges.
The first step in control is to eliminate the sources of attraction and breeding. Don’t leave ripened fruit or vegetables like onions, tomatoes, or potatoes exposed; keep them in the refrigerator until the problem is resolved. Frequently clean recycling bins that hold empty bottles and cans, and make sure the contents are thoroughly cleaned before discarding. Be sure the bottoms and the sides of garbage cans are free of any small bits of food or spilled juices. Be sure the bottoms and the sides of garbage cans are free of any small bits of food or spilled juices. (See more ways to prevent fruit flies.)
Even when all sources of attraction are removed, those speedy adult flies can scatter and lay eggs in a drain or another hard-to-reach location, so the cycle starts all over again. A pyrethrum-based aerosol insecticide may be used to kill adult flies if you can hit them, but that won’t take care of any eggs or larvae lurking in your kitchen.
Traps are important control tools that continue to eliminate new adults as they emerge. Commercial traps can be purchased at hardware stores. Disposable Fruit Fly Traps ($15.50 for a set of two), which are baited with a nontoxic lure, can catch about 2,000 flies each, and last for one month, are available from Lee Valley Tools (leevalley.com).
A homemade trap can be made by forming a cone-shaped funnel with an 8-by-10-inch piece of paper, sealing it with tape, and sticking it into a clean jar or wine bottle. Bait the jar with a teaspoon of apple cider vinegar or a slice of ripe banana. Place one or more of these traps on counters or in pantries where the pests are seen most often. The flies go in easily but can’t fly out. After you trap all visible flies, kill them with spray or release them outside. Rebait and replace jar traps, if necessary.