A new glyphosate resistant weed species confirmed for northern New South Wales and the world: common sowthistle (Sonchus oleraceus)

摘要

Two populations of common sowthistle (Sonchus oleraceus L.) were reported to survive straight applications of glyphosate in northern New South Wales. These were subsequently proven to be glyphosate resistant following applications of glyphosate at 720g a.i. ha"1. This news represents the first reporting and confirmation of a glyphosate resistant Sonchus species internationally. It is now the seventh recognised glyphosate resistant weed in Australia.Growth stage of common sowthistle at the time of treatment had a noticeable effect on the survival rates. The disparity in control between resistant and susceptible populations was more pronounced once common sowthistle surpassed the early stem elongation stage. In essence, it appears that control of glyphosate resistant common sowthistle may be feasible if treated at the early rosette stage, even with glyphosate. This interaction between growth stage and glyphosate resistance status is common amongst other glyphosate resistant weed species (Cook 2008).These findings have serious implications for grain and cotton producers in the northern region and for those that manage non-crop areas, such a roadsides and railway corridors. These areas have often relied heavily upon glyphosate as their herbicide of choice. The alternative options may not be as effective and as robust as glyphosate.