Thirty-three different species of weeds are now reported to have developed resistance to herbicides commonly used in Australian farming systems, says Dr Chris Preston, programme leader for the Weeds CRC.
The worst offenders are annual ryegrass, wild radish and wild oats.
And of the thirteen ‘families’ of chemicals used to control weeds, resistance to ten has now been found in various agricultural weeds, Dr Preston says.
“Those ten groups of herbicides, as you’d expect, are the ones that are most commonly used in our cropping systems,” he adds.
In a few areas of Australia the herbicide resistance problem has become so acute that there are no longer any herbicides available to control particular weeds – such as annual ryegrass – in some crops.
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