Abstract Farming began in Australia and New Zealand after the arrival of European settlers, who brought with them many of the weeds that later infested their cropping systems. Herbicides have since become the dominant form of weed control in both countries. Early active ingredients, such as 2,4-D, were unable to control all types of weeds, sparking the development of many other herbicides with different modes of action. While most of the land in these countries is used for pasture, many crops are also grown, with an emphasis on grains, including wheat, barley, and oats, as well as horticultural crops in New Zealand such as wine grapes, kiwifruit, and apples. An overreliance on herbicide use due to their high level of effectiveness for weed control has led to the evolution of herbicide-resistant weeds, with some weed populations developing resistance to multiple herbicide modes of action. Integrated weed management practices have been adopted by many farmers to reduce the reliance on herbicides, although widespread uptake is yet to occur. These practices use non-chemical methods in combination with herbicides to deal with hard-to-control and herbicide-resistant populations, as well as reduce the risk of resistance development. In addition to resistance, other concerns surrounding herbicide use also exist, such as the impact of herbicides on human health and the environment. This review summarizes the history of herbicides in Australia and New Zealand and discusses the issues surrounding their use as well as potential future directions for sustainable weed control.

ABSTRACT Purple nut sedge (Cyperus rotundus L.) is a problematic weed in plasticulture tomato (Solanum lycopersicum L.) production in Iran as it is difficult to control due to its ability to penetrate plastic mulch. Field trials were carried out at the experimental area of the state farm Safadasht, Shahriar region, Iran, over the fall of 2015 and spring of 2016 to investigate PRE- and POST herbicide programs (PRE transplanting, POST transplanting, and combination of PRE- and POST transplanting) to control purple nut sedge in plasticulture tomato production. PRE herbicide treatment metribuzin and (S)-metolachlor were not effective when applied alone, and did not reduce purple nut sedge plants compared to the weedy control. POST transplanting application of halosulfuron did not significantly affect purple nut sedge plants at 12 wk after application (WAA) in the fall 2015, but treatment favorably reduced density of purple nut sedge at 16 WAA in both seasons. PRE transplanting application of metribuzin or (S)-metolachlor plus POST halosulfuron exerted the greatest control, and purple nut sedge numbers were eventually diminished in both seasons. Experimental treatments did not negatively affect tomato height and yields. Based on our findings, multiple PRE and POST herbicide programs were effective in greater purple nut sedge suppression compared to the lone application of PRE and POST herbicides. The herbicides were selected due to routine use by tomato producers in the area. Using active ingredients from the various herbicide families with different modes of action could facilitate effective management of herbicide-resistant purple nut sedge in tomato fields.