Invasion of Colorado potato beetle,Leptinotarsa decemlineata,in China: dispersal,occurrence, and economic impact

Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), is a global destructive pest of potato, Solanum tuberosum L. (Solanaceae). It is also an important quarantine pest in China, but its dispersal history, occurrence, and economic impact in China have not yet been reported. We determined the current distribution of CPB and reconstructed its dispersal routes. We also investigated the density of CPB in China in 2006, 2007, 2009, and 2010, and estimated the economic impact of CPB in China. In 1993, CPB was first detected in Xinjiang and subsequently spread eastward. The CPB entered China at three distinct points in Xinjiang: in Huocheng County, Tacheng City, and Habahe County. As of 2010, CPB had invaded 38 counties and cities in China, with a distribution area of 277 000 km², between 42°40′–48°28′N and 80°15′–90°41′E. The distribution area could be divided into four zones (from south to north): Ili River Valley, northern slope of the Tianshan Mountains, Tacheng Basin, and Altay. The average annual dispersal rates in the four zones were 18, 45, 12, and 24 km year^?1, respectively. In China, CPB seriously damages potato, impacts eggplant, Solanum melongena L., and occasionally harms tomato, Solanum lycopersicum L. The current annual economic loss caused by CPB in China is estimated to be 3.2 million USD. The potential annual economic losses after completion of its invasion in China is estimated to be 235 million USD. Future invasion pathways, factors affecting CPB dispersal, and control measures were discussed.