Potential Ecological Distribution of the Beetle Agrilus mali Matsumura (Coleoptera: Buprestidae) in China under Three Climate Change Scenarios, with Consequences for Commercial and Wild Apple Forests

Simple Summary The apple buprestid beetle Agrilus mali is a pest that can cause serious harm to various domestic apples and many species of Malus. Currently, it is distributed in 17 provinces of China. After spreading from Shandong province to Xinjiang Uygur Autonomous Region, it has caused great damage to the local wild apple resources. China is a major producer of apples; once this pest spreads, it will seriously affect China's apple industry. We used the MaxEnt model to analyze the changes in the distribution area of A. mali under future climate change scenarios in China. The forecasted suitable regions for A. mali in China will expand northward in the 2050s and 2070s. The forecasted highly suitable regions were 1.11-1.34 times larger than they are currently, and their central distributions were 61.57-167.59 km further north. These findings suggest that monitoring and management measures should be implemented urgently to protect the commercial apple industry and wild apple resources alike.Abstract The apple jewel beetle (AJB), Agrilus mali Matsumura (Coleoptera: Buprestidae), is a dangerous pest of commercial apple orchards across China, the largest apple production country in the world, and has recently become invasive in the Xinjiang Uygur Autonomous Region (XUAR) of northwestern China, where wild apple forests also occur. This pest poses a serious threat to apple production and wild apple forests throughout the world. Global warming is expected to change the geographical distribution of A. mali in China, but the extent of this is unknown. Based on empirical data from 1951 to 2000, a MaxEnt model was used to forecast the ecological distribution of A. mali under three different climate scenarios projected in the fifth report of the Intergovernmental Panel on Climate Change. The results showed that the most important variables were the maximum temperature of November, precipitation in January, and minimum temperatures in April. Under all climate scenarios, the forecasted suitable regions for A. mali in China will expand northward in the 2050s and 2070s. The forecasted highly suitable regions will be 1.11-1.34 times larger than they are currently, and their central distributions will be 61.57-167.59 km further north. These findings suggest that the range and damage caused by A. mali in China will increase dramatically in the future. Monitoring and management measures should be implemented urgently to protect both the commercial apple industry and wild apple resources.