Herbicide resistance survey results of the Northern cropping region

Abstract

Take home message
• Glyphosate resistant weeds are present in the northern region. Glyphosate failed to control all of the fleabane populations tested. Glyphosate resistance was also prevalent in feathertop Rhodes grass, windmill grass and awnless barnyard grass, with resistance detected in 68%, 58% and 36% of populations, respectively. Only 14% of sowthistle populations were resistant to glyphosate
• Evolved herbicide resistance to haloxyfop was also detected in feathertop Rhodes grass, albeit at a low frequency
• Other herbicides such as 2,4-D amine, propaquizafop and clethodim provided good control of the broadleaf and grass weeds tested
• Farmers and agronomists should incorporate non-chemical weed management tactics to ensure sustainability of current herbicides
• These survey results provide a first glimpse into the state of herbicide resistance in key crop weeds for Queensland and the Northern region.