Fruit Fly Infestations

Fruit Fly Infestations

Fruit fly infestations normally happen in the spring and summer but can be active throughout the year indoors. Under normal circumstances, fruit flies are brought into the residence on fruit and vegetables purchased at the grocery store. However, they are small enough to fly through the standard window or door screen and can enter the home that way when fruit and vegetables or grown or stored outside. Because the primary food and reproduction sources of fruit flies are fruit and vegetables, the first avenue of preventing an infestation is to clean fruit and vegetables coming into the home and keep them refrigerated.

Clues That Fruit Flies Are Breeding in Your Home

A few flies around a ripening banana is normal in a Florida summer. A breeding population looks different:

• Flies that keep returning to the same spot after the obvious fruit is gone, such as the sink, trash can, a pantry corner or one particular drain.
• Tiny white larvae in overripe fruit, in liquid at the bottom of a trash can, or in a soggy corner of the recycling bin.
• Small brown pupal cases stuck to the sides of fruit bowls, bins or containers, where mature larvae crawled to pupate.
• Flies resting on walls and ceilings near the kitchen, especially in the evening.

To test a drain, tape a clear plastic bag or cup over it overnight. Flies trapped inside the next morning mean that drain is a breeding site. Do the same with any floor drain or crack you suspect.

Outdoors, Florida yards add their own sources: dropped citrus, mangoes, figs or other fruit, compost piles, and garbage cans kept near the back door. Flies breeding there move inside through doors and screens. Indoors, they follow the smell of fermentation, so ripening produce on the counter, open wine, homemade ferments and sticky juice spills are the main draws.

Numbers usually rise in late spring and summer and when backyard fruit ripens, but in air-conditioned Florida homes fruit flies can show up in any month. To make sure you’re dealing with fruit flies and not another small kitchen fly, see our fruit fly identification page.