Efficacy and environmental runoff impact of alternative pre-emergent herbicides to diuron applied on trash blanketed ratoons

THE EFFICACY OF alternative pre-emergent herbicides to diuron applied just after harvest on green trash blanketed ratoons was investigated in three field trials in the wet tropics, Far North Queensland. The study also compared the losses of the tested pre-emergent herbicides in runoff using rainfall simulations. The commercially available pre-emergent herbicide Bobcat?i-MAXX (imazapic + hexazinone), was as efficient as Barrage (diuron + hexazinone), while other tested active ingredients like imazapic, isoxaflutole and amicarbazone were effective only on some weed species. All tested herbicides were found in runoff water at levels aligned with their application rate. Herbicides applied at lower application rates such as imazapic and isoxaflutole had minimal environmental runoff footprints when compared with diuron. All tested alternatives were proven more environmentally friendly than diuron.