INSECT RESISTANCE TO ENGINEERED CROPS DECODED
Subject: INSECT RESISTANCE TO ENGINEERED CROPS DECODED...........
Date: Sat, 4 Aug 2001 09:52:58 -0400
From: Stephen Tvedten <steve@getipm.com>
Organization: Get Set Inc. (www.getipm.com)
To: Paul Helliker <phelliker@cdpr.ca.gov>
Director, State of
California, Department of Pesticide Regulation
cc: Christine Whitman whitman.christine@epa.gov
Dear Mr. Helliker, I thought you might like to read an article entitled:
INSECT RESISTANCE TO ENGINEERED CROPS DECODED
WASHINGTON, DC, August 3, 2001 (ENS) - Two reports published this week could help scientists understand why some insects develop resistance to genetically engineered crops that produce their own insectides.
Engineered crops with built in insecticides are becoming a popular tool for controlling agricultural pests. But some experts believe that using those modified crops could backfire by forcing the development of genetically resistant pests.
Now a team of geneticists has identified a gene that confers high levels of resistance in a common agricultural pest - a discovery which will allow farmers and government officials to take early steps to prevent uncontrollable outbreaks.
Roundworms exposed to the Bt toxin normally show damaged internal organs (Two photos courtesy UCSD)
The geneticists, from North Carolina State University (NC State), Clemson University and the University of Melbourne, studied the DNA of the tobacco budworm moth, which feeds on a variety of crops and has developed resistance to most conventional chemical insecticides.
They found a recessive gene that gives the moth resistance to natural toxin from the soil bacterium called Bacillus thuringiensis (Bt). Several crops - including cotton, which is a host plant for the moth's larvae - have been genetically encoded with the insecticidal Bt toxin, which kills all budworm moths except rare individuals that contain a pair of the recessive genes.
"Not only will knowledge about this gene enable us to detect the early signs of pests evolving resistance to the current engineered plants, it may also allow us to modify the plants so they will be defended against the new pest strains," said Dr. Fred Gould, the William Neal Reynolds Professor of entomology at NC State and a co-author of the report.
A second study, by biologists at the University of California - San Diego (UCSD), details the genetic and molecular means by which roundworms, and perhaps insects, can develop resistance to Bt in engineered crops and in traditional crop sprays. The team found that a mutant gene deletes a particular enzyme from the roundworms, which they hypothesize prevents the Bt toxin from attacking the pests' cells.
Resistant roundworms fed Bt toxin show no damage to their internal structures
"There are insects in the wild now that contain gene variants that allow them to be resistant to Bt toxins, but fortunately they are small in number," said Raffi Aroian, an assistant professor of biology at UCSD who headed the study. "However, as more crops with Bt genes are planted, it's only a matter of time before populations of Bt resistant insects grow numerous enough to become economically troublesome to farmers hoping to control these insects."
"But now that we know this mechanism of resistance, we can devise strategies to cope with this," added Aroian.
Both reports appear in today's issue of the journal "Science."
Well Mr. Helliker, I also believe that using these modified crops will backfire by forcing the development of genetically resistant pests in the very same way your "registered" POISONS have created super/resistant pest species. When will it be "legal" (in your opinion) to use safe and far more effective (unregistered) alternatives to actually control even resistant pest problems?
Respectfully, Stephen L,Tvedten
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