Biotech Insects To Be Tested

By tinkering with genes, scientists have made tomatoes that stay fresher longer, crops that are immune to weedkillers and fish that grow faster. Now, a genetically engineered insect is emerging from the lab.

The first field trial of a biotech insect - a pink bollworm moth that contains a jellyfish gene - is planned for this summer. The gene gives the moth larvae a fluorescence that allows scientists to more easily track them and monitor their behavior.

If the experiment — involving a major pest to cotton growers — goes as planned, scientists are ready with their next step: testing a biotech version, called the "Terminator" by farmers, that is sterile, but sexually active; it is designed to mate with wild relatives and eliminate their offspring.

Some 3,600 moths with the jellyfish genes are to be set free under screened cages in a government-owned cotton field near Phoenix. The next step would be to add genes that make the moths sterile.

"We're being very, very careful about what we're doing," said Robert Staten, an Agriculture Department scientist who will run the field trial.

The experiment is being conducted and regulated by department's Animal and Plant Health Inspection Service because of its authority for controlling plant pests. Staten expects the agency to grant approval this spring for the release.

"We're going to take as conservative an approach as we can and still move forward," he said.

Some biotech critics are alarmed while some scientists who support the technology say the government is not prepared to properly regulate biotech insects.

Under development, for example, are disease-preventing mosquitoes that could deliver vaccines to the people they bite or carry their own antibiotics.

"When you're talking about insects you're talking about extremely promiscuous organisms that will mutate and breed quite uncontrollably," said Charles Margulis, an anti-biotech activist with the environmental group Greenpeace.

He said there is no guarantee that an insect designed to be sterile will turn out that way.

The pink bollworm moth infects about 500,000 acres of cotton in the Southwest. Farmers have three options to control them: spraying a lot of insecticide; planting an expensive variety of genetically engineered cotton that makes its own insecticide; or by releasing moths sterilized by irradiation.

Irradiated moths are less effective in areas with heavy infestation because the treatment damages the insects so much that they are slow to mate. The genetically engineered moth is designed to have the same sexual prowess as its wild cousins.

"He'd be fully sexually aggressive and go out and meet and breed. He'd be the first guy in the bars at night," said John Benson, a farmer in California's Imperial Valley and a member of the California Cotton Pest Control Board, which has funded the research through producer fees.

"We see this as the one sure way to get erdication," he said.

It takes 60 irradiated moths for every wild one to make sure there are enough to mate and eliminate the chance of offspring. With the biotech moths, a 5-1 ratio is sufficient, said Thomas Miller, a University of California-Riverside entomologist who developed the moth.

The biotech moths would be cheaper for farmers to use than the gene-altered cotton, Miller said. The biotech cotton, although highly effective, costs farmers up to $30 an acre more than conventional cotton.

Some biotech critics are concerned that overuse of the gene-altered cotton, known as Bt for the insecticide it contains, will lead to an increase in insect resistance to Bt sprays, which are used on fruit and vegetable crops.

Use of a biotech moth to control pink bollworm infestations makes that resistance less likely to develop, said Charles Benbrook, an agricultural consultant to environmental groups.

This summer's experiment with the biotech moths will be conducted in three cages, each about 12-feet wide by 24-feet long. The cotton field in which they are placed is surrounded by a 6-foot chain link fence to deter vandals. There is little chance of the moths escaping "barring a major weather catastrophe," according to the application for the release.

As a precaution, the moths containing the jellyfish genes will be irradiated to ensure that even if they do escape they can't reproduce. The gene-altered moths will then be studied to see if there is any unusual behavior.


©MMI The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed
  • CBSNews.com staff CBSNews.com staff

Comments