Trends in herbicide resistance in Australia and New Zealand

The first case of herbicide resistance was recorded in New Zealand in 1979 and in Australia in 1982. As this chapter shows, since then, the trajectories of herbicide resistance in the two countries have been different. In Australia, 55 weed species have evolved resistance to at least 1 herbicide compared to 22 weed species in New Zealand. The chapter discusses the ways differences in cropping systems and climate between the two countries contribute to these contrasting outcomes.