
Triple Whammy Makes Nuisance Flies Flee the
CoopBy Tara Weaver January 21, 1999A triple whammy of chemicals, lime and parasitic wasps could bring relief to
people and farm animals plagued by nuisance house flies,
Agricultural Research Service scientists
report. Pesticides alone arent enough to control these house flies, because
the pests have developed resistance to cyromazine, a popular growth regulator
added to feed that passes through the chicken and kills the fly larvae in the
manure. To find the most effective controls for the flies, ARS researcher Jerome A.
Hogsette, in collaboration with scientists from the Institute of Agricultural
Microbiology and Zoology in Buenos Aires, Argentina, conducted field tests in
commercial poultry houses with cyromazine-resistant house flies. The scientists found the best system for reducing house fly populations
included limited-use of topically applied cyromazine, which is more
concentrated than the feed additive; chemical pesticides; cultural control such
as lime; and two parasitic wasps--Spalangia endius and Muscidifurax
raptor. The wasps were released at a rate of five of each species per hen per week
after pesticide applications were stopped. The wasps are found worldwide,
including the United States, and do not bite or sting people or animals. They
only attack flies. Combining these control practices reduced flies by 98 percent and resulted
in a 3.5 percent cost savings compared to chemical treatments alone. Also,
combined treatments resulted in a 2 to 3 percent labor savings a week. Hogsette has also tested black dump flies in controlling house fly
populations. A dump fly can kill up to 20 house fly larvae per day during its
5- to 7-day development. Black dump flies in animal manure can reduce house
flies by almost 100 percent. The flies work best in moist conditions, whereas
the wasps need a much drier environment, so the combination would prove highly
effective. Hogsette is with the Mosquito and Fly Research Unit of ARS Center for Medical, Agricultural and Veterinary Entomology in Gainesville, Fla. ARS is the U.S. Department of Agricultures chief scientific research agency. Scientific contact: Jerome A. Hogsette, Mosquito and Fly Research Unit, ARS Center for Medical, Agricultural and Veterinary Entomology, Gainesville, Fla., phone (352) 374-5912, fax (352) 374-5922, [email protected]. U.S. Department of Agriculture | |