June 1980 - The Medfly Invades Southern California

Closeup of a Mediterranean Fruit Fly
Closeup of a Mediterranean Fruit Fly. Infestations in Southern California have sparked a battle against the pest throughout the 1980s. | Photo: Alvegaspar/WikiMedia

On June 5, 1980, a male Mediterranean Fruit Fly was captured in Northridge, beginning the decade-long battle against the agriculturally-damaging invasive pest.

The Mediterranean Fruit Fly, or "Medfly," native to Africa, has historically been an established pest in southern Europe, Australia, and Central America. The insect, slightly smaller than a housefly, with its characteristic spotted, triangular wingspan, has wreaked havoc by laying its eggs in various fruit crops, whereby its larvae would render the fruit unsuitable for human consumption. The climate of California made the state an ideal breeding ground for the pest, which would potentially cause destruction to the state's agricultural industry, particularly its apricot, apple, avocado, citrus, grape, guava, and tomato crops, among many other fruits and vegetables.

The first Medfly was captured in California in Culver City in the fall of 1975, though none further were detected until June of 1980 when, in addition to the Northridge capture, other specimens were captured in San Jose on that very same day. Later in 1980, other specimens were found in San Diego County. Further captures of medfly specimens continued on through the course of the decade, into the early 1990s. Medflies have been found or captured in Ventura, Los Angeles, Orange, San Bernardino, Riverside, and San Diego counties.

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The eradication of the medfly has proven difficult costing hundreds of millions of dollars, as ground-level spraying has proved logistically difficult. Quarantine areas were established in infested areas, restricting the transportation of fruit through those communities. Aerial spraying from agricultural helicopters dropping the chemical malathion was the prefered system of extermination, although its environmental effect on human and animal health has been controversial and hotly debated, as aerial malathion spraying, particularly over working class communities, has become an environmental justice issue in many communities. Malathion spraying began in the San Fernando Valley in 1980, followed by a program in Baldwin Park in 1981, with subsequent aerial sprayings -- usually conducted at night -- in other communities over the next several years.

The release of sterile medflies into the wild has been met with some success, though its application requires ideal conditions in order to work. Other methods include the placement of local trapping and killing stations in infested areas.

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