Losing The War On Weeds

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You ask any farmer and she will tell you that weed management was always part and parcel of farming. An army of out-of-control weeds, however, has been taking over millions of acres of the nation’s farmland as a result of the increasing ineffectiveness of glyphosate, the active ingredient in Monsanto’s flagship herbicide, Roundup. This resistance, which can be directly traced to to the widespread adoption of crops genetically modified to withstand continued application of glyphosate, has many farmers returning to the very same practices that the “miracle” of Roundup and herbicide tolerant GMOs was supposed to eliminate. Spraying more glyphosate, using more toxic herbicides, pulling weeds by hand and tillage, and more plowing that’s the “miracle” of Roundup.

The battleground in weed resistance was set in 1996, when farmers started increasingly planting glyphosate-tolerant GMOs and thus relying on a single system for weed management, glyphosate.

The excessive use of glyphosate associated with continuous planting of Roundup Ready crops is responsible for a growing worldwide epidemic of weeds that have evolved resistance to this chemical, alarming the world’s agronomists. Millions of acres of cropland have become infested with glyphosate-resistant weeds in the U.S., Argentina and Brazil, precisely those countries that rely most heavily on RoundUp Ready crops, leading to a vicious cycle of increasing pesticide use and evolution of still greater levels of weed resistance. (Bill Freese, 2009, Why GM Crops Will Not Feed The World, GeneWatch, Vol. 22, Issue 1).

What makes these “superweeds” different is that they grow fast, big and wide in a matter of days. Pig weed, for example, is a superweed that “grows up to three inches a day, and at its base it’s as thick as a baseball bat. It kills crops and destroys heavy machinery, keeping farmers from bringing their combines and cotton pickers into the fields.”

According to several studies published in the recent Weed Science journal, currently, there are at least 21 different species of weeds resistant to glyphosate. “The herbicide resistance issue is becoming serious,” the Weed Science journal’s editor, William K. Vencill, said. “It is spreading out beyond where weed scientists have seen it before.” Actually, independent scientists have predicted that massive reliance on glyphosate tolerant GM crops will lead to dependence on glyphosate long before GMOs dominated the U.S. soybean, cotton and corn fields. “Prior to the confirmation of the first glyphosate resistance weed population in 1996, weed scientists had collected abundant evidence showing that resistant weeds were likely to evolve with frequent use,” stated Bill Freese, the Science Analyst for the Center for Food Safety, in an answer to questions posed by the Domestic Policy Subcommittee of the House Oversight and Government Reform Committee last summer. Indeed, “[t]he more a chemical is used consistently, the more likely that somebody’s weeds will become resistant. That’s standard, agreed-upon science,” recently commented Doug Gurian-Sherman, the senior scientist at the Union of Concern Scientists.

The Roundup star is fading, a problem that not even a planned spending of a millions of dollars on questionable cash and trade incentive programs for Roundup, now under Securities and Exchange Commission’s scrutiny, would fix.

In the first few years, the Roundup Ready system worked incredibly well. But after a few years, the shifts in weed communities got bad enough that farmers had to apply the herbicide a second or third time. And because some of the weeds weren’t as sensitive to glyphosate, farmers began adding a new family of herbicide chemistry into their program. This is when both the cost of weed control in the Roundup Ready system and the volume of herbicides applied started to quickly rise. That’s been the story for almost a decade now, and it’s been getting progressively worse every year. (Dr. Charles Benbrook, pesticide policy expert and weed resistance specialist).

So what’s the solution the the 10-12 million acre weed resistance problem?

The industry would have you believe that the solution lies in more glyphosate applications or applications combining other herbicides. “Monsanto and other pesticide firms assure us that the solution to glyphosate-resistant weeds lies in a dizzying array of new crops resistant to older, more toxic herbicides like 2,4-D  and dicamba, and to multiple herbicides. DuPont envisions a single crop resistant to seven or more different classes of herbicides,” noted Bill Freese during his testiomy before the Domestic Policy Subcommittee of the House Oversight and Government Reform Committee on September 30, 2010.

Applying more herbicides as a solution to herbicide resistance, however, is a flawed model. From a health and environmental perspective, “[t]here are three big risks that are going to go up as 2,4-D and Dicamba are sprayed more widely: birth defects and reproductive problems, damage to non-target vegetation, and impacts on aquatic ecosystem.” From an economic perspective, resistance to herbicides brought about by a slavish dependence on glyphosate begs the question of why farmers should buy the more expensive manipulated seeds and then invest even more in chemical products to grow those seeds. “The diminishing effectiveness of glyphosate, as demonstrated in the dramatic increase in glyphosate tolerant weeds, destroyed any benefit from the technology,” Troy Roush, an Indiana farmer, told the Domestic Policy Subcommittee of the House Oversight and Government Reform Committee in September of last year.

Inevitably, GM crops manipulated to tolerate multiple herbicides and/or pesticides lead to an evolution of weeds resistant to several herbicides simultaneously.

Already, common waterhemp resistant to three and four classes of herbicides are rampant in Missouri and Illinois.  Weeds can acquire resistance to herbicides one at a time, or to several at once via a mechanism known as metabolic degradation.  The evolution of weed resistance to several herbicides simultaneously will be fostered by increased use of herbicide mixtures with multiple [herbicide resistant] crops, a very troubling development. (Bill Freese)

It is said that the definition of insanity is doing the same thing over and over again and expecting different results.  Instead of dramatically escalating chemical warfare in the fields, it is time that we reverse our course and the current predominant agricultural model in favor of a more ecological approach.  There is a steady stream of reports showing that organic or agroecological methods could improve biodiversity, soil conditions, the livelihoods of farmers, and outperform the use of chemical fertilizers all the while working with the natural environment to protect crops against pests.  It is time for us to evolve too.

What would the world be, once bereft Of wet and wildness? Let them be left, O let them be left, wildness and wet, Long live the weeds and the wildness yet.” ~ English poet Gerard Manley Hopkins