Sunday, June 10, 2012

Who's afraid of "superweeds"?

A recent post in The Atlantic decries that appearance of RoundUp-resistant weeds popping up in fields of GM crops, and uses this a call for the abandonment of GM technology.

Amaranthus hybridus
The only problem in his thinking is that "superweeds" started popping up way before the advent of GM technology and the deployment of RoundUp-resistant crops. For example, atrazine was one of the most widely used herbicides in eradicating plant growth on road shoulders, and is still widely used in agriculture. Weeds resistant to atrazine started to be noticed in the 1970s. My Ph.D. adviser Joseph Hirschberg isolated the first gene for herbicide resistance in 1983 from an atrazine-resistant Amarnthus hybridus that had been isolated from the side of a highway. This was way before any GM crops had been developed.

So as long as herbicides will be used in modern agriculture, there will always be the problem of spontaneous resistance, just as as long as we use antibiotics, antibiotic-resistant bacteria will also crop up.  GM technology is not the cause of the resistance. The challenge is in designing the best use of herbicides to ensure the best agricultural yields for the farmers, while protecting our environment as best as possible.But that's the subject of another blog.


  1. Thanks for reminding people of this point. I would add only that while GMOs with herbicide tolerance don't cause superweeds (although some of the geneflow to wild and weedy brassicas might be a counter-argument) they do make it a heck of a lot easier for selection to operate.

    1. Thanks Jeremy for making sure I don't over simplify the issue.