TAMPA, Fla. (AP) _ A substance found in laundry detergents may be a safe alternative to the controversial pesticide malathion in the battle against the crop-destroying Medfly, two scientists say.

``If you want to compare malathion with borax in the way we propose to use it, this thing is safe. Period,'' said Herb Nigg, one of the scientists.

Nigg and colleague Sam Simpson, who work at the University of Florida Citrus Research and Education Center in Lake Alfred, recently received a U.S. patent for their idea. They say borax works by preventing female flies from laying eggs.

Agriculture officials today use malathion to kill the Mediterranean fruit fly. The treatment has been controversial. In 1997, more than 700 health complaints were reported after widespread aerial spraying of malathion in a four-county area of Tampa Bay.

The fly, smaller than a household fly, targets 250 kinds of vegetables and fruits, especially citrus. State officials fear that if an infestation gained a foothold, it would threaten Florida's $7 billion agriculture industry.

Nigg and Simpson say a low concentration of borax _ about one-half of 1 percent in water-based bait _ stopped egg production in female flies for up to seven days.

Borax is especially attractive because it has a long history of safe human use, the scientists said.

``It's a very common chemical, found in many households,'' Nigg said.

In California, which has been dealing with fruit flies longer than Florida, scientists were intrigued by the borax idea.

``My hat's off to anybody who's after this,'' said James Carey, a professor of entomology at the University of California-Riverside. ``We're all intensely trying to find some alternatives to malathion. And my gut feeling is, borax is as good as any.''