Impacts of climate change on weeds, insect pests, plant diseases and crop yields: Synthesis

Three distinct components of climate change in the recent times are warming of the earth, increased levels of carbon dioxide in the atmosphere and erratic changes in water availability to plants. These changes in the global climate not only impact the growth and life cycles of plants but also affect their pests. Recent research demonstrates that the effects of climate change on pests, pesticides (their efficacy and post-application chemistry) and pest management are complex. This is important to document changes in the behaviour of pests and pesticides in the wake of climate change and propose pest management strategies accordingly. Nevertheless, non-chemical methods and integrated pest management will play an important role in sustainable pest control under climate change. Further, the effects of climate change factors on crop protection and crop production are desired to be understood in order to maintain the global food supplies and global food security

Virus infection mediates the effects of elevated CO2 on plants and vectors

Atmospheric carbon dioxide (CO(2)) concentration has increased significantly and is projected to double by 2100. To increase current food production levels, understanding how pests and diseases respond to future climate driven by increasing CO(2) is imperative. We investigated the effects of elevated CO(2) (eCO(2)) on the interactions among wheat (cv. Yitpi), Barley yellow dwarf virus and an important pest and virus vector, the bird cherry-oat aphid (Rhopalosiphum padi), by examining aphid life history, feeding behavior and plant physiology and biochemistry. Our results showed for the first time that virus infection can mediate effects of eCO(2) on plants and pathogen vectors. Changes in plant N concentration influenced aphid life history and behavior, and N concentration was affected by virus infection under eCO(2). We observed a reduction in aphid population size and increased feeding damage on noninfected plants under eCO(2) but no changes to population and feeding on virus-infected plants irrespective of CO(2) treatment. We expect potentially lower future aphid populations on noninfected plants but no change or increased aphid populations on virus-infected plants therefore subsequent virus spread. Our findings underscore the complexity of interactions between plants, insects and viruses under future climate with implications for plant disease epidemiology and crop production