GM crops may result in superweeds

Growing GM crops may lead to the creation of ''superweeds'', according to leading weed scientist Professor Stephen Powles from the Western Australia Institute of Agriculture.

A new wave of glyphosate-resistant weeds is sweeping through North and South America due to the massive use of glyphosate-resistant or Roundup Ready crops, Powles said, a statement that is in direct opposition to a pro-GM farmers group that claimed GM crops will lead to less weed resistance.

At least eight major weed species had developed resistance to glyphosate as a direct result of the glyphosate-resistant crop evolution, he said.

Glyphosate has been successfully used without any major resistance issues for more than 35 years mainly because it has been used in conjunction with other herbicides, but the appearance of glyphosate-resistant crops means glyphosate is now nearly the only herbicide used across huge areas in the US, Argentina and Brazil, Powles said.

Bob Phelps, spokesman of non-GM group Gene Ethics, said glyphosate-resistant weeds could become an unmanageable problem.

However, pro-GM Producers Forum national convenor Jeff Bidstrup said farmers using GM crops were forced to use chemicals other than glyphosate when rotating crops.

Bidstrup said GM crops will reduce the likelihood of glyphosate resistance because it forces farmers to use other chemicals to destroy GM weeds.

Glyphosate is used to kill weeds and is the most used herbicide in the US, where 85-90 million pounds are used annually in agriculture.