Herbicide-Resistant 'Superweeds' Signal GM Crop Setback

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KD Weber <wvadreamin

Tuesday, 24 June 2003 3:48

 

 

Herbicide-Resistant 'Superweeds' Signal GM Crop Setback

By Michael McCarthy

Environment Editor

The Independent - UK

 

6-23-3

 

http://www.rense.com/general38/beh.htm

 

 

The dispute over genetically modified crops will intensify today

with news of the evolution of " superweeds " , which are resistant to the

powerful weedkillers that GM crops were engineered to tolerate.

 

The development, which comes as the sacked former environment

minister Michael Meacher puts himself at the head of the anti-GM campaign,

will be seized on by opponents of the technology as undermining its

rationale.

 

It means that bigger quantities of weedkillers - not less, as the

biotechnology companies have claimed - will be needed in GM-crop fields,

adding to the already intensive agriculture that has wiped out much of

Britain's farmland wildlife in the past four decades. Monsanto, the GM

market leader, confirmed to The Independent at the weekend that its solution

for dealing with resistant weeds was to apply different weedkillers in new

ways.

 

In yesterday's Independent on Sunday, Mr Meacher accused Tony Blair,

a GM supporter, of seeking to bury health warnings about GM produce by

" rushing to desired conclusions which cannot be scientifically supported " .

 

The revelations about superweeds have been communicated to the

Government by an American academic specialising in weed control, who has

posted a paper on the website of the official GM science review, led by

Professor David King, the Government's chief scientific adviser. This will

report soon in advance of a long-delayed decision, due this autumn, on

whether GM crops should be commercialised in Britain.

 

The paper, by Professor Bob Hartzler of the Department of Agronomy

at Iowa State University, reveals that in the past seven years, up to five

weed species have been found with resistance to the herbicide glyphosate,

best known by the Monsanto trade name Roundup. The resistance has come about

not through gene transfer from GM herbicide-tolerant crops, as some have

feared, but through natural evolution.

 

Glyphosate is a " broad spectrum " herbicide, meaning that,

originally, it killed everything, including crops. GM crops were developed

to be tolerant of the herbicide, so it could be applied throughout the

growing season.

 

Two GM crops proposed for commercial growth in Britain, fodder beet

and sugar beet, are glyphosate-tolerant. But weeds have been found in

Australia, Chile, Malaysia and California and other areas of the US, that

glyphosate cannot kill.

 

Greg Elmore, Monsanto's US technical manager for soybeans, said

Monsanto was taking seriously the question of glyphosate resistance,

tackling it with " weed control management practices " .

 

With soybeans, he said, resistant weeds were controlled with a

pre-planting " burn-down " (which kills everything), using 2,4-D, another

weedkiller.

 

At least three of the resistant weeds had evolved where glyphosate

was being used with non-GM crops, he said, adding that it was far from the

only weedkiller for which weeds had evolved resistance - as many as 70 weeds

were resistant to some weedkillers.

 

Pete Riley, Friends of the Earth's GM campaigner, said: " Companies

like Monsanto have spun GM crops and their weedkillers as having less impact

on the environment, but the fact of resistant weeds undoubtedly means more

weedkillers, and means the impact on the environment will be greater.

 

" These discoveries remove a central plank from the whole argument

for GM crops. "

 

Yesterday, Mr Meacher listed a series of reports and findings

suggesting that the full impact of GM technology was still dangerously

unpredictable. Many of the health tests carried out were " scientifically

vacuous " , he said.

 

 

© 2003 Independent Digital (UK) Ltd

 

http://news.independent.co.uk/uk/environment/story.jsp?story=418070