Fruit Flies: The Red Eye Guys

Fruit flies are small, but not microscopic, have short life cycles and can reproduce rapidly in tiny spaces with limited resources. These characteristics make fruit flies the model organism for genetic research, but are the very reason why fruit flies are such a nuisance when they appear in our homes.

Identification and Biology

Fruit flies are 1/8 inch long and typically have red eyes. They are one of the smallest and most common flies in houses, restaurants and grocery stores – anywhere food ripens, rots and ferments. Fruit flies begin as eggs before they hatch into legless larvae or maggots. The maggots enter a pupal stage so they can develop into mature, winged adult flies. They are active year round indoors, but their life cycle will slow considerably at cooler temperatures. Under optimal conditions in the summer, they can complete their life cycle in 7-10 days.

Fruit fly

The fruit fly has red eyes, two wings, and dark stripes on the abdomen. Photo by Jody Green, Nebraska Extension in Lancaster County.

Food Sources and Breeding Sites

Some of the most common breeding sites and food sources include rip and rotting bananas, tomatoes, squash, melons, potatoes, and onions. If these are not present, fruit flies can develop in any moist film of fermenting material in trash containers, drains, empty wine bottles and pop cans, garbage disposals, mops, dishcloths and discarded food containers. Prior to pupation, the maggots will migrate to a drier location, not far from the breeding site. Adults are good fliers, attracted to lights and therefore found flying around people’s faces a considerable distance from the source of the infestation.

Fruit fly maggots

Fruit fly larvae or maggots in rotting fruit. Photo by Jim Kalisch, UNL Department of Entomology.

Fruit fly puparium

Empty fruit fly puparium on a dish cloth. Photo by Jody Green, Nebraska Extension in Lancaster County.

Locate the Source of the Infestation: 

Here is a checklist to help you find the source:

  • Kitchen counter where the fruit (banana, apples, peaches, mangoes, melons, tomatoes) is stored.
  • Cupboards and pantry where non-refrigerated foods (potatoes, onions) are stored
  • All places where trash, compost and to-be recycled items are collected (cupboards, stand-alone trash bins, garage, home bar)
  • Lunch boxes, bags, coolers and food storage containers that may have been forgotten. Check desk drawers, vehicles, under desks and chairs.
  • Drains and garbage disposable. Make sure they are clear from decaying organic matter and in working order.
  • Pet food bowls. Don’t forget to check the fruit and vegetables from reptile or insect terrariums.

Making a Homemade Fruit Fly Trap

Once the source is removed, the adult flies can be trapped using a homemade fruit fly trap that includes a small container (glass or plastic cup), 2 drops of dish soap and apple cider vinegar. These traps are easy to clean and reuse.

The apple cider vinegar attracts the fruit fly and the soap breaks the surface tension so when the fruit fly falls in the liquid, it cannot escape. I use a salt/pepper shaker from the dollar store as my container; It doubles as handy-dandy bug collecting jar that every entomologist should have on hand. Some people put plastic wrap over their container and poke holes in the plastic with a toothpick to let the flies enter. This also works well. Remember that the trap will be most effective once the source of the infestation is removed.

Some Tips on how to Prevent Fruit Flies in the Home

  • Examine fruit and vegetables in the grocery, farmers market or garden before bringing them inside the home. Look for blemishes, bruises and rotten parts.
  • Only pick, purchase and bring in as much produce as your family can consume before it spoils.
  • When fruits and vegetables are ripe, store them in refrigerator.
  • If you have fruit trees on your property, practice sanitation for ripe or rotting fruit.
  • Keep doors closed, install and fix screens to keep fruit flies out.
  • Rinse trash cans and recycle bins so that fermenting residue does not build up and attract flies.
  • Use a plastic liner that can be discarded with the trash regularly.
  • Rinse pop cans, wine bottles, beer bottles, food packaging before discarding.
  • Launder dishcloths, dry mops and sponges.
  • Sanitize countertops and drains.
  • Run the garbage disposal often.
  • Cover food with lids or netting.
  • Small fans and air currents can keep flies off food.

I hope this information can help you get those pesky fruit flies out of your home.

Stay calm and respect critters,

Jody

*Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by the University of Nebraska–Lincoln is implied

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