The kitchen is one of the busiest places in the house about now. Home-grown tomatoes line the countertops, waiting to be eaten or canned, but those veggies can also bring unwanted visitors — fruit flies.
Some call them vinegar flies, pomace flies or kitchen gnats. They’re very tiny, but get up close and personal with them, and you may notice their red eyes and black-and-tan body.
These flies are common anywhere there is ripening or fermenting fruit. You may even see a couple at the grocery store hovering above ripened bananas. Right now, they are common in my own kitchen, where a couple of tomatoes were left on the counter past their prime.
Fruit flies lay their eggs in fermenting organic matter. If you think the flies are small, the eggs are only 0.5 mm long. It doesn’t take long for the eggs to hatch, about 24 hours. The larvae immediately start eating at or near the surface of the rotting areas of the fruit. Because of this, it is acceptable to cut off overripe portions of fruits and vegetables and consume the rest.
The larvae begin to pupate near the food source. Then the adult flies emerge, the ones you see swarming around garbage cans and food sources. The whole life cycle is completed in a week. A female fly can lay up to 500 eggs in her lifetime — now you see why the population seems to explode in the kitchen.
Once the life cycle of the fruit fly starts indoors, it can escalate quickly. Flies are usually brought in on overripe fruit. They can also come in through cracks in windows and doors.
Preventing fruit flies
The best thing to do is avoid the situation.
1. Dispose of overripening fruits and vegetables quickly; a compost pile is one of the best ways to do this.
2. Store vegetables properly.
Controlling fruit flies
Once a fruit fly problem is established, several methods must be used to reclaim your kitchen.
1. Eliminate any and all breeding grounds. This means clearing the counter and pantry of all ripening vegetables that could be breeding stations for the fly.
2. Take trash cans out and wash them. Any scrap left in the can or stuck to the sides is a potential breeding site.
3. Clean kitchen drains, especially disposals. Use a brush to remove food residues on the sides of the drain, and pour boiling water down the drain.
4. Also clean your mop, which could serve as a breeding site if debris from the kitchen floor is on the mop.
5. Pyrethrum-based insecticides labeled for indoor use can be used to control adults, but remember the many eggs that are yet to hatch.
6. Build a simple trap to use in the kitchen and other rooms in the house where fruit flies have become a problem. (Fruit flies originating in the kitchen may find solace in the bathroom, where they are attracted to the moisture.)
- Piece of paper
- Cider vinegar, for bait (you can also use slices of banana or wine).
Roll the sheet of paper into a funnel. Pour a couple of inches of vinegar into the jar. Insert the funnel into the jar.
Adults flies, attracted to the vinegar, will fly into the jar through the funnel, and be unable to fly out.
Danielle Carroll is an extension agent for the Alabama Cooperative Extension System.