Glyphosate, the world’s herbicide of choice, may be a victim of its popularity
While debate continues over the pros and cons of planting sugar beets genetically modified to be “Roundup Ready” [see A Time to Plant, a Time to Sue], it appears that nature has done some re-engineering of its own to produce weeds that can stand up to the leading herbicide.
According to latest pesticide market estimates from the Environmental Protection Agency, the world spent almost $15.75 billion on herbicides, with top consumer US accounting for almost a third of expenditures, in 2007. Not surprisingly, the agricultural sector accounts for nearly 80% of conventional pesticides used in the US. And the pesticide active ingredient most commonly used is glyphosate.
In fact, glyphosate, the main ingredient in Monsanto’s Roundup, has been the most used active ingredient in agriculture since 2001, the year Monsanto’s flagship weed killer went off-patent, and a lower-cost generics started entering the market. The new entrants began to take share from Monsanto – but the company was already shifting its focus to seeds and genomics, including the glyphosate-tolerant sugar beets currently at issue.
The roster of genetically modified organisms [GMOs] granted deregulation (effectively, permission to buy, sell and plant) by the USDA’s Animal and Plant Health Inspection Service (APHIS) lists 14 glyphosate-tolerant plants, including varieties of alfalfa, corn, cotton and soybeans. According to the National Research Council, GMOs accounted for over 80% of soybean, corn, and cotton acreage in the US in 2009.
Naturally, the availability of glyphosate-tolerant GMOs has encouraged greater reliance on glyphosate herbicides. Enter the recently evolved Palmer pigweed, a major headache for cotton growers who can’t kill it with Roundup or its generics and have had to go back to “chopping cotton” according to this account. There are also new strains of horseweed and (sniffle) giant ragweed. At least 10 weeds possessing the glyphosate-tolerant trait have been identified.
The US produces most of the glyphosate-based herbicide it consumes domestically, but it imports the “glyphosate technical” (active ingredient) used to make the “glyphosate formulation” (finished herbicide). China is the leading source for glyphosate technical. Last year, a US company requested an investigation into whether China was dumping its formulations on the US market. Indeed, the trade data shows China overtaking first the UK, then Canada, to become the top source for US herbicide imports between 2007 and 2010. During this period, China expanded glyphosate production capacity with the aim of exporting the output. But the Chinese government subsequently ended its export tax rebate for the herbicide and adopted policies aimed at consolidating its herbicide industry. The anti-dumping complaint was withdrawn.
There are alternatives to glyphosates. For example, Bayer CropScience cut prices on its Ignite herbicide for last year’s growing season. And, yes, the CropScience division of the German multinational also markets “LibertyLink” GMOs that tolerate glufosinate, the active ingredient in Ignite.