Fruit flies are those tiny, bothersome flies you often see buzzing around your kitchen, especially when the weather warms up. If you’ve noticed small flies or gnats hovering near your fruit bowl or garbage can, chances are you’re dealing with fruit flies. While they can appear any time of year, fruit flies are particularly prevalent in late summer and fall because they are strongly attracted to ripening and fermenting fruits and vegetables. Understanding what attracts them and how they live is key to getting rid of them.
Identifying Fruit Flies: Biology and Appearance
Fruit flies are common pests found in homes, restaurants, grocery stores, and anywhere food is allowed to rot and ferment. Adult fruit flies are quite small, typically only about 1/8 inch long. A key characteristic for identification is their usual red eyes, though some species may have darker eyes. Their bodies are typically tan on the front portion, transitioning to black towards the rear.
Fruit flies have a rapid life cycle. They lay their eggs near the surface of fermenting foods or other moist, decaying organic matter. Once hatched, the larvae, which are also tiny, continue to feed near the surface of this material. This surface-feeding behavior is important to note because it means that if you catch fruit or vegetables starting to spoil, you can often cut away the damaged portions without needing to discard the entire item, as any larvae would likely be concentrated in the decaying part. Fruit flies are prolific breeders; a single female can lay around 500 eggs in her lifetime. Remarkably, the entire life cycle, from egg to adult, can be completed in about a week under favorable conditions.
Fruit Fly Behavior and Breeding Habits
As their name suggests, fruit flies are strongly drawn to ripened and fermenting fruits and vegetables, making kitchens a prime location for them. However, their breeding grounds aren’t limited to just fruit bowls. They will also reproduce in drains, garbage disposals, empty bottles and cans, trash cans, and even damp mops and cleaning cloths. Essentially, fruit flies need only a moist film of fermenting material to breed.
Infestations frequently start with fruits or vegetables brought into the home that were already infested, perhaps with eggs laid on them before purchase. Adult fruit flies can also enter homes from outside, especially if window and door screens aren’t in good repair.
While often considered just a nuisance, fruit flies are more than just annoying. They have the potential to contaminate food with bacteria and other disease-causing organisms as they move between breeding sites and food preparation areas.
Prevention: Keeping Fruit Flies Away
The most effective strategy for managing fruit flies is prevention. This means eliminating what attracts them and where they breed.
- Manage Produce: Ripe produce should be promptly eaten, discarded, or refrigerated. Overripe fruits and vegetables left at room temperature are magnets for fruit flies.
- Inspect and Discard Damaged Portions: If you find cracked or bruised areas on fruits or vegetables, cut away and discard these sections immediately, as they may contain eggs or larvae.
- Clean Regularly: Even a small amount of spilled fruit juice or a forgotten rotting potato or onion can support a large fruit fly population. Regularly clean up spills and don’t leave produce out in the open for extended periods. Remember to check less obvious places, like under refrigerators, for spills or forgotten produce.
- Empty and Clean Recycling Bins and Trash Cans: Recycling bins, especially those containing food and beverage containers, and kitchen trash cans should be emptied and cleaned frequently to remove potential breeding materials.
- Seal Home-Canned Goods Properly: If you can your own fruits and vegetables or make wine, cider, or beer, ensure containers are tightly sealed. Fruit flies can lay eggs under loose lids, and larvae can then enter the contents after hatching.
- Use Screens: Install and maintain tight-fitting screens (16 mesh) on windows and doors to prevent adult fruit flies from entering your home from outside.
Eradication: Getting Rid of an Infestation
If fruit flies have already taken hold, eradication requires finding and eliminating all breeding sites. Simply killing adult flies won’t solve the problem if the larvae continue to develop. Locating breeding sources can sometimes be tricky and requires careful inspection and persistence.
- Inspect Drains and Disposals: Potential breeding sites like garbage disposals and drains can be checked by taping a clear plastic food storage bag over the opening overnight. If fruit flies are breeding there, adults will emerge and be trapped in the bag.
- Eliminate Breeding Sources: Once you identify breeding areas, thoroughly clean them. This might involve cleaning drains with a brush and drain cleaner, sanitizing garbage cans and recycling bins, and removing any spoiled produce.
After eliminating breeding sites, you can address any remaining adult flies.
- Insecticides (Use with Caution): A pyrethrum-based aerosol insecticide can be used to kill adult flies. However, this is a temporary solution if breeding sites aren’t removed. Always use pesticides responsibly and according to label directions.
- Fruit Fly Traps: A more effective and less chemical-intensive approach is to use a fruit fly trap. A simple and effective trap can be made using a jar, cider vinegar, and a paper funnel. Pour a few ounces of cider vinegar into a jar and insert a paper funnel into the jar opening, with the narrow end pointing down into the vinegar. The scent of the vinegar attracts the fruit flies, they fly into the funnel, and then often get trapped and drown in the liquid. Place traps wherever fruit flies are most active.
By focusing on prevention and diligently eliminating breeding sites, you can effectively manage and get rid of fruit flies and keep your kitchen pest-free.
Source: University of Kentucky Entomology
