Fact vs. Fiction: Fruit Flies

Photo courtesy of University of Wisconsin-Madison.

Fiction: I have a bunch of fruit flies, but they all look different.
Fact: Not all small flies are fruit flies. Many flies are found in the same environment and are similar
in size and appearance. Drain flies are fuzzy and heavy bodied. Phorid flies have a distinctive hump back. Vinegar flies (Drosophila melanogaster) are the most commonly occurring indoor fruit fly and have bright red eyes, which are clearly visible, even without a microscope. Ask any high school biology student.

Fiction: Fruit flies only eat fruit.
Fact: Fruit flies are attracted to and feed on decaying fruits and vegetables, drinks (including beer and wine), spills, coffee grounds, drains, trash cans, dirty mops, towels, damp clothing, moist pet food and indoor houseplants. If it’s damp and remotely edible, fruit flies and their larvae will use it.

Fiction: Fruit flies don’t carry disease.
Fact: Fruit flies have hairy bodies and sticky foot pads that spread bacteria and filth, which cause diarrheal diseases.

Fiction: You can tell by looking whether food is contaminated by fruit flies.
Fact: Although they don’t poop and vomit when they land, female fruit flies – much like house flies — are egg-laying machines. Fruit can appear normal on the outside, but be brown on the inside thanks to fruit fly activity. When cutting away overripe parts, be careful to remove any trace of eggs or larvae.

Fiction: The only way manage fruit flies is by spraying.
Fact: Sanitation is the key to managing fruit flies. The life cycle of Drosophila is about 10 days. A drink spill, a sour mop, unwashed towel or dirty trashcan liner can harbor thousands of eggs and larvae. Spraying will harvest some of the adults, but unless harborage areas are cleaned regularly and proper storage practices are put in place, the vicious cycle will continue. pmp

You can reach the McGoverns at jeffreymcgovern@mindspring.com.