Assuring Crop Protection in the Face of Climate Change Through an Understanding of Herbicide Metabolisms and Enhanced Weed Control Strategies

Abstract

The prevention and management of weeds have been difficult throughout the history of food production. We are now entering into a new era where new challenges are arising more rapidly due in part to the rapid population growth, which places an unprecedented demand upon both natural and agricultural ecosystems to fulfil food, fibre, and feed for at least another two billion people by 2050. Climatic change is associated with a higher frequency of extreme weather events, and it is generally agreed that this will have a drastic impact on ecosystem productivity and biodiversity. The present world atmospheric temperature has increased by 1.0 °C since 1900 with half of this rise coming in the past 30 years. Crop production is directly affected by the direct effects of climate change (temperature and water stress) and indirect effects of increased competition from weeds and other pest species. In a field situation, crop plants are inevitably surrounded by an assemblage of C3 and C4 plants, and a considerable variation in the growth response of weeds to climate change have been reported. In this chapter, we present an overview of the impact of temperature rise, carbon dioxide increase, and changed rainfall patterns on weed composition, distribution, abundance, and our current approaches to weed management. There is a high risk that some weed species will shift their range with the change in temperature and precipitation patterns. The efficacy of chemical weed control depends on the environmental conditions before, during and after the herbicide application. The changes in physiology, morphology, and anatomy of plants will result in altered weed growth, crop-weed competition, and herbicide efficacy under elevated temperature and/or carbon dioxide. Global warming may increase the risk of evolution of nontarget site resistance mechanisms against herbicides in the weed plants and thus decrease herbicide efficacy. The anticipated actions in these areas are also discussed in the end which may enhance our understanding of the impact of climate change on the practice and future of weed management and crop production.