By:
Chuck Woods (352) 392-1773 x 281Source(s):
Dan Culbert dfculbert@ifas.ufl.edu, (863) 763-6469
Phil Koehler pgk@ifas.ufl.edu, (352) 392-2484
Roxanne Rutledge-Connelly crr@ifas.ufl.edu (772) 778-7200 ext. 158
OKEECHOBEE, Fla.—Add another annoyance to the list of hurricane-related problems plaguing residents in some South Florida counties: swarms of fruit flies feeding on rotting fruit knocked off trees by the storms.
The fruit flies — also known as vinegar flies because they are attracted to yeast on rotting fruit — are finding their way into homes through damaged screens or by hitchhiking their way into kitchens or pantries in shopping bags that contain fruits or vegetables, University of Florida entomologists say.
The insects are troublesome in citrus-growing areas of the state where hurricane winds were strong enough to blow fruit off the trees.
“A visit to your local produce section at your favorite supermarket may introduce you to an unwanted friend — courtesy of hurricanes Charley, Frances and Jeanne,” said Dan Culbert, an Okeechobee County extension agent with UF’s Institute of Food and Agricultural Sciences, or UF/IFAS. “With an abundance of moisture and decaying vegetation in many South Florida counties, there’s a population explosion of these pesky fruit flies, especially in areas where citrus is a major crop.”
Phil Koehler, a UF/IFAS professor of entomology in Gainesville, said vinegar flies typically have red-colored eyes and two very small wings that allow them to quickly hover on both fresh fruit and decaying vegetable matter. They are about one-eighth of an inch in length, brownish-black to brownish-yellow in color and have a feathery bristle on the antennae.
Koehler, an urban pest management specialist, said the insects — whose scientific name is Drosophila melanogaster — are favorites with researchers studying genetics because of many variations in their body structures.
“There are several other small flies that may be confused with vinegar flies,” Koehler said. “Eye gnats, hump-backed flies and moth flies are generally darker in color and are also fond of decaying waste materials. The vinegar fly is also smaller than any of the real fruit flies, such as the dreaded Mediterranean fruit fly or the Caribbean fruit fly.”
Koehler said vinegar flies usually have a short life cycle. Each female lays about 500 eggs, which hatch into maggots (larvae) that mature to adults in nine to 12 days. Maintaining a home environment free of flies for two weeks should break the infestation cycle in local areas.
Proper sanitation is the best way of controlling vinegar flies, he said. Flies will seek breeding places where garbage, manure or vegetation residues accumulate. Dropped fruit, dirty garbage containers or slime in drains provide organic materials that support the yeasts that grow on organic matter.
“In the yard, keep compost piles covered with leaves and soil until the swarms of vinegar flies abate,” Koehler said. “Clean up any remaining fruit that the hurricanes have knocked to the ground and collect other fruit as it drops to the ground.”
Chemical insecticides are not recommended for controlling vinegar flies in the kitchen because food, utensils and preparation surfaces may become contaminated. Outdoors, the use of approved insecticides may be an effective way to control the flies and break their reproductive cycle.
Well-fitting screens on windows and doors are essential to prevent flies from entering homes and kitchens. Choose a mesh of 16 or more to ensure the screen holes are smaller than the flies.
Traps also can be purchased or constructed to catch vinegar flies. Roxanne Rutledge-Connelly, an assistant professor of entomology at the UF/IFAS Florida Medical Entomology Laboratory in Vero Beach, said traps can be created by putting a small bowl of fly bait — wine or balsamic vinegar — in a larger bowl of sudsy water. Flies attracted to the bait will land in the water and get trapped in the bubbles.
“While I’m not sure of how effective they will be, carnivorous plants such as sundews and pitcher plants may also be used to capture and consume the vinegar insects,” Culbert said.
Residents unsure of what is winging in their wine or festering in their fruit should capture a couple of the bugs, put them in a closed container and bring them to the Okeechobee County extension office for identification. The address is 458 Highway 98 North, Okeechobee.
For additional information on vinegar flies, including recommendations on pesticide products labeled for controlling them, contact the Okeechobee County extension office at (863) 763-6469 or okeechobee@ifas.ufl.edu, or visit http://okeechobee.ifas.ufl.edu.
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