The formation of outbreak populations of Sogatella furcifera (Horváth) in theWuling Mountain area: A case study in 2007
Author of the article:CAO Shu-Pei1** YIN Li2 LU Ming-Hong3 ZHAI Bao-Ping1***
Author's Workplace：1. Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; 2. Hunan Plant Protection Station, Changsha 410005, China; 3. National Agricultural Technical Extension and ServiceCenter, Beijing 100125, China
Key Words：Sogatella furcifera, southwest vortex, trajectory analysis, landing mechanisms
Abstract： [Objectives] Successive outbreaks of the white-backed planthopper, Sogatella furcifera (Horváth) (WBPH) in the Wuling Mountains have seriously damaged rice production. Better understanding of the outbreak mechanisms of this species is important to improving the accuracy of outbreak forecasting and the integrated management of this pest. [Methods] Wind and temperature fields were simulated by the mid-scale atmospheric models WRF and GrADS. The trajectories of immigrant WBPH were tracked by the NOAA atmospheric dispersion model, HYSPLIT. Source areas and landing mechanisms of immigrant WBPH in the Wuling Mountains in 2007 were studied by trajectory analysis and synoptic analysis. [Results] (1) Southwest low level jet streams were the primary conditions for the early formation of outbreak populations of WBPH in the Wuling Mountains. Precipitation, downdrafts, geographical obstacles such as mountain ranges, and low temperatures are barrier factors that impede early immigration events. (2) The main outbreak period coincides with prolonged periods of high temperature and dry weather in southern China which stimulate massive numbers of WBPH to migrate. Immigrant populations of WBPH are much more abundant than before in the Wuling Mountains. Prolonged precipitation over several days is thought to be the main factor causing large numbers of WBPH to land and preventing the migration of local populations. (3) Vertical vortices and other microclimatic factors caused by topography are the reason for site-specific differences in migration.[Conclusion] A southwest, warm, moist air flow generated by subtropical high pressure systems over the Western Pacific frequently meets the cold air flow generated by the cold vortex over Northeast China in the Wuling Mountains causing long-term and large-scale convection. In addition, convergence of the southwest vortex caused outbreaks of WBPH in the Wuling Mountains in 2007.