GMW: U.S. scientists warn of GM superweed risk

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GMW: U.S. scientists warn of GM superweed risk

" GM WATCH " <info

Thu, 18 Aug 2005 18:16:43 +0100

 

 

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EXCERPT: intensive use of the herbicide combined with the non-rotation

of glyphosate-resistant GM crops is expected to increase the problem

and it will develop on " a global scale, " the paper says.

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Scientists warn of GM superweed risk

Paul Brown, environment correspondent

Thursday August 18, 2005

The Guardian

http://www.guardian.co.uk/gmdebate/Story/0,2763,1551238,00.html

 

Scientists have identified 15 weed species that are resistant to a

herbicide widely used on GM crops and are warning farmers they may

become a

serious problem unless a strategy for dealing with them is developed.

 

Some of the most common weed species, including types of ryegrass,

bindweed and goosegrass either have some strains with a natural

resistance

to the widely used GM herbicide glyphosate or have developed one.

 

Writing in the journal Outlooks on Pest Management, four scientists

argue there is a danger that by ignoring the threat these weeds pose,

farmers may be giving them a huge advantage over other plants which are

killed by glyphosate.

 

Even where they did not previously thrive on farmland or were in a

minority of weeds, farmers may be creating a new niche for them among

arable crops which would allow them to multiply rapidly.

 

The paper is published alongside an assessment of the three-year

farm-scale trials of GM oilseed rape, sugar beet and maize in Britain.

All

three crops are glyphosate-resistant and, if the American researchers are

right, would be troubled by glyphosate-resistant weeds if grown

commercially in the UK.

 

Glyphosate has been used by farmers to kill off weeds for 30 years but

since the 1990s, when GM crops were modified to resist glyphosate, its

use has mushroomed.

 

The paper says that worldwide use has increased from 5,000 tonnes a

year in 1995 to more than 30,000 tonnes in 2002, and has increased since.

 

However, intensive use of the herbicide combined with the non-rotation

of glyphosate-resistant GM crops is expected to increase the problem

and it will develop on " a global scale, " the paper says.

 

The researchers, based at the State University and the Southern Weed

Research Unit in Mississippi, are concerned that the widespread

usefulness of an extremely efficient weedkiller will be lost if

farmers do not

take precautions.

 

" The problem of glyphosate-resistant weeds is real, and farmers have to

realise that the continuous use of glyphosate without alternative

strategies will likely result in the evolution of more

glyphosate-resistant

weeds.

 

" Even in the short term no one can predict the future loss of

glyphosate efficiency due to weed species shifts and evolution of

glyphosate

resistance, " says Vijay Nandula in the conclusion to the paper.

 

He advises farmers to treat land with additional herbicide to kill off

the weeds before they multiply sufficiently to cause a problem.

 

 

 

 

 

 

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