Surveillance and characterisation of prominent grass weeds in cropping regions of the Western Australian grain belt for better management of herbicide resistant weeds

Herbicide resistance is a common problem worldwide. Here we have surveyed the Western Australian grain belt to quantify the extent of herbicide resistance in grass weed species. Resistance in annual ryegrass is widespread and has increased over time, while resistance in wild oat, brome grass and barley grass is lower and has remained stable. Concurrent with resistance evolution, seed donnancy levels were found to be high in many annual ryegrass populations, with increased dormancy correlated with intensive cropping and herbicide resistance. These results advance our understanding of weed dynamics for the benefit of the agriculture industry.