Linking warmer temperatures, greater insecticide use, and worsening pest outbreaks

Global climate change and landscape simplification have potential to augment pest populations on many of the world’s agricultural crops, warranting increasing pesticide use despite waning societal tolerance. How these factors interact to influence levels of pest pressure has yet to be empirically demonstrated. Here, we examine climatic, landscape, and operational drivers of insect activity and abundance using sweet potato whitefly (Bemisia tabaci Gennadius) detections in a trapping network sampled at weekly intervals in 2018 and 2019 throughout south Georgia, USA. We found that whiteflies were generally detected earlier and became more numerous at sites that were warmer and that occurred in counties with higher insecticide use rates. This interaction was not driven by application of insecticides specifically to control whitefly, supporting a role of more intense insecticide use at a landscape scale in reducing natural pest suppression. Peak whitefly detections at low trap heights occurred earlier in counties with more vegetable acreage, and later at high trap heights at sites with greater cotton acreage, likely reflecting the influence of spring vegetable host plant availability on population growth rates and the effect of cotton harvest on mass dispersal in autumn, respectively . This study provides empirical support for the idea that global warming and rising pesticide use act synergistically to augment economically damaging pest populations. More broadly, our findings premise that coordination of management efforts to promote robust ecological interactions in agricultural landscapes is needed to sustain agricultural productivity under increasingly intense shifts in climate and societal demands.