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Update: Resistance Bites Again


by Bill Chameides | March 23rd, 2010
posted by Erica Rowell (Editor)

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It seemed like a great idea — genetically modifying cotton to kill its much-feared pest, the pink bollworm. But those bollworms are turning out to be peskier pests than conglomerate Monsanto bargained for. (USDA)

News flash in the GMO world: the worm has turned.

They say that familiarity breeds contempt. An axiom should be that overuse breeds resistance.

A case in point: through our overuse of antibiotics, we are inadvertently breeding strains of bacteria that can invade and decimate our bodies rendering doctors helpless to stop them. Why? Because the drugs designed to attack them no longer work. We’re breeding antibiotic-resistant bacteria.

We’re Creating Super Bugs and Super Pests, Too

Another type of resistance-breeding we technologically savvy humans excel at is with pests.

Repeated use of pesticides can encourage the rapid evolution of pests that are resistant to the chemicals we’ve concocted to eradicate them. Entomologist Robert G. Bellinger, from Clemson University, noted [pdf] that as of the mid-1990s:

  • more than 500 insect (see example) and mite species were resistant to pesticides and
  • some 17 insect species were resistant to all major classes of insecticides.

And the resistance doesn’t stop there. Now resistant to their former fatal pesticidal foes are:

  • more than 270 weed species (examples here and here),
  • more than 150 plant pathogens, and
  • about a half dozen species of rats. (Holy rodent empire, Batman!)

In each case, the development of these resistant bugs (be they bacteria or pests) necessitates the development of new, more powerful antibiotics or pesticides to replace the ineffective one. It’s a grand race between the forces of Darwinian evolution and the forces of modern technology.

Now comes news of a new wrinkle in the resistant-breeding/new-killer-technology race. Why a new wrinkle? Because it involves the development of bacteria-resistant pests.

Some years ago, Monsanto, the world’s largest seed-producing company, came up with what seemed like a great idea for keeping the feared pink bollworm out of cotton, the world’s largest insecticide-consuming crop, according to the United Nations.

Through genetic engineering Monsanto created a new kind of cotton — a genetically modified organism, or GMO, cleverly called Bollgard. The GMO in this case has a gene from the bacterium Bacillus thuringiensis (Bt) that allows it to secrete a toxin that stops a bollworm dead in its tracks. In one fell swoop two problems are eradicated — the bollworm, which is done in when it chows down on the cotton (did I hear anyone say just desserts?), and the need to spray insecticides, so there’s less environmental impact. What’s not to like?

Bollixing the Bollworm Battle

The product has been enormously successful for Monsanto, especially in India where some 83 percent of last year’s cotton crop was genetically modified.

But Science reports that trouble’s brewing in Bollgard-world. It seems that Monsanto has “detected unusual survival” in the pink bollworms munching down on their Bollgard cotton. In other words India’s cotton-crunching bollworms are becoming resistant to the toxin-secreting Bollgard. And this is not the first report of pests developing resistance to GMO crops with the Bt gene. I guess you could say that when it comes to GMOs, the worm has turned.

No worries, however, because Monsanto’s got a new GMO waiting in the wings: Bollgard II. Early commitments suggest that 80 percent of Indian farmers will be making the switch to Bollgard II. That should be a relief for cotton-growers and cotton-wearers alike. Oh and did I mention: Bollgard II is about 15 to 25 percent more expensive than the original Bollgard. Now that’s what I call survival of the fittest.

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