ngin - Norfolk Genetic Information Network

18 December 2002


The US is being hit by Roundup Ready resistant weeds and an independent market research study, which has been discreetly circulating and has been seen by GM WATCH, says Roundup Ready resistance is set to hit the economic value of farmland wiping around 17% off US land rentals. What's more, 46% of the farm managers surveyed in the study said weed resistance to glyphosate, the active ingredient in Monsanto's herbicide Roundup, is now their top weed-resistance concern.

The report warns, "Suddenly, glyphosate-resistant weeds have become more than an in-season production and profitability issue. They can also affect the long-term value of farmland". It also says, "These survey findings should make both farm managers and landowners take notice" because "The economic consequences are significant" and can represent for landowners "a major loss of cash flow".

Glyphosate is being massively used in North America thanks to Monsanto's GM herbicide-resistant 'Roundup Ready' crops. But there is growing concern among weed scientists and land owners about the emergence of glyphosate-resistance. As the report notes, "The high volume of glyphosate being used across the country as a result of RR technology adoption makes this a very real concern for growers, professional farm managers and the owners of farmland."

Glyphosate-resistant marestail has already been found in Delaware, Tennessee, Kentucky, Indiana and Ohio. Marestail (horseweed) is a prolific seed producer and the seeds are easily blown around by the wind so this is a major problem. But the problem doesn't stop there. Glyphosate-resistant rigid ryegrass has been reported in California. Weed scientists in Iowa and Missouri are already testing waterhemp from fields that seem to be showing more tolerance to glyphosate. There are also complaints about marginal control of velvetleaf, ivyleaf morningglory and lambsquarters control with glyphosate.

The latest bad news for Monsanto, which has always promoted Roundup as a way of simplifying farm management issues, comes courtesy of its main rival, the world's largest biotech company, Syngenta, which commissioned the  market research study report and has been quietly circulating it to farmers and landowners via its PR company, Gibbs & Soell.

Syngenta hopes to profit from the wave of concern over Roundup resistance as people rush to use extra chemicals, and crop rotations not involving RR crops, to try and head off the build up of glyphosate resistance on their land.

But American famers using Roundup Ready crops could be headed up a cul-de-sac.

According to weed scientists, such as Iowa State University's Mike Owen, it's doubtful whether this kind of resistance management will be viewed as economically feasable at elast in the short term. As Owen told a packed-out meeting of North Central Weed Science Society in St. Louis recently, he expects growers to try and carry on using glyphosate in the same way to try and avoid the extra expense of other chemicals until they are finally forced by resistance to switch to something else. But an article reporting on the Weed Science Society meeting concludes, "With few, if any, new blockbuster chemicals in the pipeline, the question may become whether there will be alternative programs to switch to if glyphosate loses its effectiveness." [see "Glyphosate resistance dominates weed science meetings", Mike Holmberg, Farm Chemicals Editor, Successful Farming December 6, 2002,]

Among the CONCLUSIONS in the Syngenta report:

*Specific weed resistance can reduce a farm‚s rentable value by 17 percent

*The greatest weed-resistance concern is glyphosate tolerance in RR crops

*More than half of farm managers placed it ahead of their concerns about weed resistance to atrazine, Pursuit, ALS herbicides or propanil

*Almost two-thirds (63 percent) of these professional farm managers expect the importance of glyphosate tolerance to increase in the future when determining rental values and land appraisals. "Given the increasing adoption of RR technology in corn,soybeans and cotton,these professional farm managers and rural appraisers felt the importance of glyphosate-resistant weeds will increase in the future.Overall, 63 percent said it will become a bigger problem."

*Almost half (47 percent)now require practices to manage weed resistance... This is expected to grow to 54 percent in the future

*Seventy percent said the use of weed resistance-management practices already influence their tenant selection.

The report also looks at western Australia, where weed resistance to herbicides is becoming a big problem for land productivity.

Syngenta's 10-page 'White Paper' describing the research and the results is available as a pdf (requires Acrobat) on line:

Or e-mail your request for a copy of the report to Jennifer McManus of Gibbs & Soell at <>

ngin bulletin archive