Monday July 24

U.S. Presses Colombia to Use Herbicide on Coca

By Diane Bartz

WASHINGTON (Reuters) - The United States is pressing Colombia to use a controversial fungus to kill coca plants, U.S. officials and others familiar with the program say.

Advocates of the fungus Fusarium oxysporum, such as Florida Republican Rep. Bill McCollum, see it as what he calls the ''silver bullet'' that can defeat coca and win the war on drugs.

The hope is that eradicating Colombia's coca industry will cripple a guerrilla movement that controls up to 40 percent of Colombia, where a 30-year internal conflict has left more than 35,000 people dead since 1990.

The program's supporters say the fungus kills only coca, used to make cocaine, and opium poppy, used to make heroin, without hurting food crops. But its detractors warn that using even an apparently benign biological agent can damage the environment and possibly hurt the farm families who grow coca.

While various strains of Fusarium have killed coca, tomatoes, corn and a host of other crops for decades, this particular strain was discovered accidentally when it decimated a coca crop in Hawaii that researchers planned to use to test chemical herbicides, said Eric Rosenquist, head of international programs at the Agriculture Department's Research Service in Beltsville, Maryland.

Rosenquist said the next step was to do field tests in Colombia to determine if the fungus killed enough of the coca it attacked to drive farmers into planting other crops, usually 40 to 50 percent.

``Conceptually it seems to work,'' he said, adding: ``It certainly is not ready to use.''

But Colombia has balked at field trials, and Environment Minister Juan Mayr said in Madrid in early July that Bogota believed Fusarium may pose ``serious risks to the environment and human health.''

Still, Bogota is under heavy pressure from U.S. drug czar Barry McCaffrey's office, the State Department and elsewhere, said a source familiar with the project.

Colombia wants to find a strain of the fungus already in the country, rather than risk introducing one from outside. This means that tests must start from the beginning and sets the program back two to three years, Rosenquist said.

In the United States, Florida has considered using Fusarium to kill marijuana plants but that program appears to have been put on a back burner because of environmentalists' objections.

David Struhs, the state's secretary of environmental protection, said in an April 6, 1999, memo that he was concerned that Fusarium applied to kill drug plants could mutate into something more dangerous.

``Mutagenicity is by far the most disturbing factor in attempting to use a Fusarium species as a bioherbicide. It is difficult if not impossible to control the spread of Fusarium species. The mutated fungi can cause disease in a large number of crops, including tomatoes, peppers, flowers, corn and vines,'' he wrote.

But Jim McDonough, director of the state Office of Drug Control Policy, said that Florida officials were ``watching to see where the research goes'' in terms of efficacy and safety.

``Personally it appears to me that the research is showing promise,'' he told Reuters.

Some of the debate over whether to use Fusarium centers on what danger, if any, the fungus poses to people.

Agriculture Department spokeswoman Sandy Miller-Hays said that the coca-killing strain of Fusarium oxysporum does not produce mycotoxins that could hurt farm families.

However, even without the mycotoxins, it is not clear that it is safe for humans to be around large amounts of the fungus, said Dr. Michael Rinaldi, a clinical mycologist who directs a fungus testing laboratory at the University of Texas at San Antonio.

People who are severely immunosuppressed because of AIDS or cancer treatments, for example, are vulnerable to Fusarium infections, and a minor eye injury may lead to blindness if Fusarium is involved, said Rinaldi, who estimates he has seen at least 100 Fusarium oxysporum infections over 10 years.

Ramon Sandin, director of microbiology and virology at the H. Lee Moffitt Cancer Center in Tampa, Florida, said he had treated cancer patients with Fusarium infections, and had been frustrated to find anti-fungal treatments often did not work.

``We're not very happy when somebody comes down with a Fusarium infection. We know the potential for demise,'' he said. ''We've lost several in the past couple of years.''

Still, a U.S. official was derisive about the notion that the fungus could hurt people, likening concerns about it to warning labels in microwaves telling people not to use the ovens to warm pets.

``There are a number of people in the U.S. Congress who are enthusiastic about this,'' the official said.

In addition to concerns about its safety, Rosenquist seemed unconvinced that Fusarium would kill enough coca to be worth pursuing. Overall, he said, just 20 percent of released biogens do what they are supposed to.

In Peru's coca-growing Upper Huallaga Valley, the fungus is endemic and has caused real economic losses to farmers. But while the Upper Huallaga Valley is tropical mountains, coca in Colombia is grown on drier savanna so it is not clear that the fungus would survive, he said.

Currently, crop-dusting planes spray Roundup (glyphosate) on coca to kill the plants. But the aircraft must fly so low that they are vulnerable to ground fire from coca-growers or rebels. Pilots would be safer spreading the fungus.

``One of the methods of applying this fungus is using an airplane to eject seeds infected with the fungus,'' the U.S. official said. ``If it could be worked out, it would enable airplanes to fly higher than when applying liquid herbicide.''