Weeds vs Herbicides: Weeds Win!
An article in The New York Times seems to celebrate weeds: their hardiness, their adaptability, their ability to quickly evolve. It’s overall theme? In the battle between weeds and chemical herbicides, weeds eventually and always win. And while it takes some reading between the lines, the article also draws conclusions that organic gardeners have known all along. One… herbicides can be dangerous. Two… a variety of techniques, many of them organic, are needed to actually reduce crop losses caused by weeds.
So why use herbicides? Their development (PDF) was thought to be a tremendous breakthrough. As far back as Roman times farmers spread salt on their fields to destroy their enemies’ crops. Modern weed killers were introduced during World War II and their use skyrocketed after that. Chemical companies soon learned that herbicides meant big money. But almost as quickly, weeds began to develop resistance to the chemicals. Today, it’s estimated that at least 217 varieties of weeds have developed resistance (follow the link to see a frightening photo of giant ragweed taking over a field of Roundup resistant corn).
Here’s one of the take-aways from the Times story:
For decades, farmers have responded to resistant weeds by turning to new herbicides. But a number of scientists argue that we need to get off this treadmill. They argue that we can find more effective ways to fight weeds by appreciating how well they’ve done at our expense.
How are chemical companies reacting to resistance? By coming up with new sprays. And if one spray won’t work? Use more, or, use two different sprays.
Of course, the other ploy has been to genetically engineer crops that are resistant to the herbicide such as Monsanto’s Roundup resistant crops. But even these herbicides are proving ineffective as weeds develop resistance to Roundup. Today, it’s estimated that half of American farms are home to Roundup resistant weeds. So how are seed companies including Dow and Monsanto reacting? By engineering crops that tolerate more and multiple herbicides.
Though it barely mentioned in the Times story, the use of herbicides has caused tremendous environmental damage as well as having health consequences in humans. New horror stories seem to pop up everyday. And evidence of the harmful effects on Roundup, the most widely used herbicide, continues to mount. But what’s a few human lives (okay, more than a few) measured against combating something that claims as little as 10% of the world’s agricultural production?
Okay, that 10% can be substantial when you’re trying to feed the world’s growing population (though most experts now agree that hunger issues don’t result from a lack of production but come from ineffective distribution). But why, when it comes to controlling weeds, should we keep using a failed solution that only does us harm? What changes need to be made?
The answer is buried in the story: common sense, multi-faceted organic solutions.
Dr. Mortensen and his colleagues are investigating controlling weeds by planting crops like winter rye that can kill weeds by blocking sunlight and releasing toxins. “You want to spread the selection pressure across a number of things that you’re doing, so that the selection pressure is not riding on one tactic,” he said.
The good news here is that many scientists are seeing the futility of trying to stay ahead of weed resistance with new and stronger chemicals. Of course, organic gardeners and farmers are way ahead of corporate agriculture on this. But then, we’re not so interested in putting the bottom line ahead of effective solutions and environmental health. Until big agriculture and chemical interests see the light, weeds win.
How do you control weeds in your lawn and garden the organic way?
• Discourage or block their growth with barriers
• Crowd them out with desired plants
• Limit available water and light
• Hand weeding
• Use of effective, natural herbicides which break down quickly in the environment
Note: Most organic herbicides work by removing or “burning” the waxy cuticle of green plant tissue. Once this protective layer is destroyed, plants dehydrate and die quickly. Weeds can NOT develop resistance to this mode-of-action.