Dumping on House Flies

House flies are in short supply in the poultry houses at Zephyr Egg near Tampa, Fla. That’s because scientists with USDA’s Agricultural Research Service teamed up with University of Florida cooperators to release a predatory fly--the black dump fly--that gobbles up house fly larvae that live in poultry manure.

Each week for a year, the scientists released 70,000 black dump flies into the poultry houses at Zephyr. The company is one of the largest egg producers in Florida, with two million chickens that can produce up to 300 tons of wet manure a day--heaven for house flies that breed in the manure.

But a single dump fly larva can kill up to 20 house fly larvae a day. Soon after releasing the dump flies, the house flies had virtually disappeared. This meant Zephyr no longer had to spray an estimated $12,000 a year in chemical pesticides to control the pests. Also, organic farmers are now interested in buying the chemical-free manure.

The black dump fly, native to the United States, will kill more house fly larvae than it can eat, making it an excellent biocontrol insect. Another plus: Dump flies won’t bother people.

Black dump fly larvae will also eat the larvae of stable flies and other pests. Black dump flies are sold commercially in the United States, Canada and Europe, and have been used predominantly in the midwestern United States. But this is the first time the flies have been used as far south as Florida to control house flies in a commercial poultry house.

ARS scientists are now working with a Florida poultry farm that wants to breed the flies in an on-the-farm insectary. The scientists also are also testing the dump flies for controlling pest flies in manure at dairy farms.

Scientific contact: Jerry Hogsette, USDA-ARS Center for Medical, Agricultural and Veterinary Entomology, Gainesville, FL; telephone (352) 374-5912; e-mail afn15308@freenet.ufl.org.