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Animal and Plant Health Inspection Service
U.S. Department of Agriculture
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Sterile Fly Release Programs

We help prevent dangerous pests from harming U.S. agriculture. These include the New World screwworm fly (Cochliomyia hominivorax), which can injure and kill livestock, and the Mediterranean fruit fly (Ceratitis capitata) and Mexican fruit fly (Anastrepha ludens), two of the most destructive pests of fruits and vegetables.

We co-sponsor screwworm and fruit fly reduction programs that leverage sterile fly release facilities in Mexico, Panama, and Guatemala to lower the risks of these flies entering the United States. These programs have successfully reduced populations of all three pests, stabilizing agricultural trade and lowering their threat to the United States.

Eradicating and Preventing Screwworms

With the Panama Ministry of Agriculture and Livestock (MIDA), we co-manage the Commission for the Eradication and Prevention of Screwworms [Comisión Panama – Estados Unidos para la Erradicación y Prevención del Gusano Barrenador de Ganado] (COPEG). Through this program, we produce and release millions of sterile screwworm flies each week. The sterile flies help reduce pest populations and maintain a biological barrier in Central America—preventing northward movement of the New World screwworm fly into new areas.

What We Do

COPEG releases the sterile insects by plane over the Darien Province in eastern Panama and 20 nautical miles into neighboring Colombia, reducing the likelihood that fertile male flies will mate with fertile females. We also conduct field surveillance for screwworms and public information campaigns to raise awareness about the pest.

Other program activities include maintaining technical expertise, keeping pace with scientific advancements to improve operational efficiency and effectiveness, developing capacity for emergency responses to outbreaks, and communicating with countries interested in eradicating screwworm. 

Contact Us

Call +(507)296-0006 (extension 2103, 2014. or 2105) for more information.

Mediterranean and Mexican Fruit Flies

The Medfly is native to the Mediterranean area but has spread to other parts of the world, including Australasia (Australia, New Zealand, and some neighboring islands) and North and South America.

The Mexfly is native to Mexico and the Caribbean. Newly hatched larvae eat and burrow into the pulp of fruits, taking on the color of their food. When they are small, they are easily overlooked. Many maggots may be found in a single fruit.

What We Do

We maintain sterile fly breeding facilities for Mediterranean (Medfly) and Mexican (Mexfly) fruit flies in in the United States, Mexico, and Guatemala. Countries seeking fly control help us fund these facilities.

In the United States, both California and Florida have preventative sterile fly release programs to control any Medflies that may enter our country. APHIS maintains a Mexfly preventative release program in Texas and conducts sterile Mexfly releases south of the border in Mexico to reduce pest pressure.

Contact Us

Call +(502) 2389-4600 for more information.

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