Skip to content
for a responsible, fair & sustainable food system

The Cost of RR Technology Failure Clear, No Relief in Sight

Immediate release (25 Sep 2013)

Calls to: Pete Riley 07903 341 065; Peter Lundgren 07751 112 303

Delegates at the American Chemical Society’s (ACS’s) 246th national meeting, held in the heart of US corn country, heard dire warnings from weed scientists about the spread of glyphosate resistant weeds and the growing number of weed species with resistance to as many as five different weedkillers. [1]

The costs of controlling weeds in Roundup Ready (RR) GM soya have seen a six-fold rise since glyphosate resistant weeds first appeared in the middle of the last decade, and GM RR cotton has seen a five-fold rise in weed control costs in recent years.

The extent of the weed control problems farmers now face growing Monsanto’s GM RR crops is clear: [all at 2]

  • The University of Missouri found that nearly two-thirds of waterhemp (Amaranthus rudis) plants sampled in Iowa in 2011/12 were resistant to glyphosate. The University of Iowa found that 89% of waterhemp samples are resistant to two or more weedkillers, and 10% are resistant to five different classes of herbicide
  • The University of Arkansas found weed control costs in RR cotton in the US South rose from US$50-75/hectare a few years ago to US$370/hectare today because of weed resistance to glyphosate
  • Southern Illinois University found that the cost of growing RR soya in Illinois rose from US$25/hectare to US$160/hectare
  • Farmers in the US cotton belt are responding to the crisis by pulling out of cotton production altogether: “[O]ver the past few years, the area planted with cotton has declined by 70% in Arkansas and by 60% in Tennessee.”

Options for finding new chemical herbicides to combat glyposate resistance are limited. Science magazine reports, “[N]o new herbicide with a novel mode of action has hit the market in 20 years…[R]esearchers at the [ACS] meeting say they know of no new herbicides on the way that have proven to be effective, short-lived, and non-toxic to other life forms.” [2]

The biotech industry’s solution is to use more glyphosate in combination or rotation with four other herbicides that GM crops have been modified to tolerate (ie, 2,4-D, dicamba, glufosinate ammonium and isoxaflutole). All four chemicals already have weed resistance problems in the US, [3 and 4] and industry advice also contributes to the steep escalation in the use of soil-acting residual weedkillers. [2 and 5]

Lincolnshire farmer Peter Lundgren commented:

This information is not what farmers want to hear. Glyphosate is widely used by arable farmers in the UK, but if Roundup Ready crops are adopted in this country it could mean resistant weeds quickly develop and spread to neighbouring farms. The nightmare scenario would be the development of glyphosate resistant Black Grass.

Knowing this, it is amazing that the hierarchy of the NFU is still enthusiastically promoting GM technology. It is even more strange given the lack of markets for any GM food crops in Europe.

Pete Riley of GM Freeze said:

The gathering of weed scientists in the US sent out a very clear message that over-reliance on glyphosate in GM crops is causing weed resistance problems to spread fast. Current alternatives are already undermined by their own resistance problems, and UK farmers should note the lack of new chemicals in the pipeline that can safely control any of these weeds.

Government Ministers’, including Owen Paterson’s, unequivocal support for GM crops seems all the more bizarre in the light of the information coming from the US.



[1] American Chemical Society, 8-12 September 2013. Chemistry in Motion meeting session “Herbicide-Resistant Crops and Weeds: Current Status”

[2] Science, 20 September 2013. “What happens when weedkillers stop killing?”

[3] GM Freeze and PAN UK, 2 August 2013. GM Herbcide Tolerant Crops: Less equals more

[4] Heap I, 2013. “The International Survey of Herbicide Resisant Weeds

[5] GM Freeze and PAN UK, 21 June 2013. The Herbicide Treadmill in Roundup Ready Crops – EU environment faces huge increase in toxic burden