Florida Fights Medflies With ... More Medflies

Release of sterile male flies steps up battle to protect the $53 billion food industry

Agriculture authorities battling Florida's worst outbreak of Mediterranean fruit fly infestation in 40 years are enlisting a special weapon in their fight against the crop destroying insect: Amour.

In addition to a controversial aerial insecticide spraying program, Florida bug experts are trying to ensure that female medflies are unable to go forth and multiply.

They are doing it, ironically, by releasing millions of male medflies from Air Force cargo planes 2,000 feet above affected areas around Tampa on Florida's west coast.

Scientists hope that the medfly bachelors - each of which has been raised in a laboratory and sterilized - will mate with a wild female, thus preventing that same female from rendezvousing with a wild male medfly.

"What makes these eradication campaigns so tough is you have to get every last female. You have to prevent that last one from laying eggs," says Gary Steck, a state medfly expert based in Gainesville.

The stakes are high. No pest poses a bigger threat to Florida's $53 billion agriculture and food-related industries than the tiny medfly.

An army of some 400 state and federal bug warriors has descended on the Tampa area. They are expected to spend $15 million to $20 million.

Medflies look like a black and yellow version of an ordinary house fly. They live for roughly one month and can lay from 300 to 800 eggs, more than enough to rekindle an infestation.

But the flies are particularly dangerous because they lay eggs inside fruits and vegetables. The nearly invisible eggs hatch as maggots that destroy the crop from the inside. They are a threat to virtually every vegetable and fruit grown in Florida, including the state's multibillion-dollar citrus crop.

"There are a lot of really terrible pests," Mr. Steck says. "This is one of the worst."

Medflies are believed to have originated in equatorial Africa. They spread to southern Africa and the Mediterranean region in the 1800s. From there they hitchhiked in contaminated fruit to tropical regions.

The first medfly outbreak in the United States came in Florida in 1929. Since then the state has had nine other outbreaks, including the last major infestation in 1956.

But Florida isn't the only state to battle medflies. California endured a huge infestation in the early 1980s. Because of the controversy surrounding the use of the aerial insecticide malathion, state officials initially balked at spraying, relying instead on the release of sterilized male medflies. The population still skyrocketed, forcing the state to undertake the unpopular spray program.

Opponents of spraying say the insecticide is bad for the environment and causes human illnesses. State and federal officials, including those in the federal Environmental Protection Agency, say harmful effects are minimal and can be managed.

Today, California's medfly population is under control. But in southern California, officials still release 350 million sterilized medflies as a prevention.

In Florida, officials released 100 million medflies last Friday over downtown Tampa and surrounding areas. Another 500 million will be released in the next two weeks.

The Florida infestation was discovered May 28 when a single male fly was caught in a monitoring trap near Tampa. Since then more than 700 of the flies have been caught, some farther north than Orlando.

Most of the Florida eradication was carried out earlier this month with the spraying of malathion from airplanes and helicopters. The spraying program prompted the formation of a group, Citizens for the Responsible Application of Malathion, which opposed spraying over large urban areas.

Julie Sternfels, a member of the group, says it is conducting a health survey of residents in areas being sprayed. She says more than 30 Tampa residents are complaining of health problems that they say are directly related to the recent spraying.

Medfly experts say it is necessary to spray in populated areas because many residents have fruit trees in their backyards.

Investigators with the US Department of Agriculture are attempting to track down how the flies were first introduced to Florida. They say medflies usually piggyback into the country inside fruit carried from overseas and that medfly outbreaks underscore the importance of agriculture inspectors at airports and seaports.

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