Formation of whitebacked planthopper Sogatella surcifera (Horváth) populations: Case studies in Qianshan,
Author of the article:ZHENG DaBing1**YANG Fan1ZHAO Yun1XU JinFeng2WU CaiLing2ZHANG XiaoXi1ZHAI BaoPing1
Author's Workplace：1Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Integrated Management of Crop Diseases and Insect Pests (Ministry of Education, Ministry of Agriculture of China), Nanjing210095, China；2Qianshan Stations of Plant Protection, Qianshan246300, China
Key Words：Sogatella furcifera, trajectory analysis, population characteristics, return population
Abstract： Qianshan County is located in southwest Anhui Province and is important to the northward and southward migration of the whitebacked planthopper Sogatella fiucifera (Horváth) (WBPH) because it is both the area in which spring migrants settle and the source area for autumn emigrants. Understanding WBPH population processes in Qianshan will therefore provide scientific and technical support for regional forecasting and source suppression. Source areas of six immigration peaks of WBPH in Qianshan in 2009 and the formation of immigrant populations were analyzed using HYSPLIT, trajectory analysis software for the simulation of migration pathways, and MICAPS (Meteorological Information Compiling, Analyzing and Processing System). The population dynamics and characteristics of WBPH were studied by systematic field surveys and dissection of female ovaries. The following results were obtained: (1) The source areas of WBPH immigrants in Qianshan were, in early June western Jiangxi and the juncture between Hunan and Jiangxi (27.2°-28.7°N), in mid and late June, southern and southeastern Hunan (25.1°-26.7°N), in early and late July, eastern Hunan and Jiangxi (27.1°-28.5°N), in mid July, southeastern Hunan and southern Jiangxi (25.5°-26.8°N), and from the end of July to the beginning of August, northern and northwestern Jiangxi(28.1°-29.4°N). (2) The period of damage inflicted by WBPH on midseason rice and lateseason rice was extended by the massive retained population in 2009 which provided sufficient recruits to migrate back to source areas. (3) The population characteristics of each generation of WBPH in mid and lateseason rice were determined by their ovarian developmental. The immigrants developed in midseason rice, and most of the newly emerged adults (the 3rd generation) were trapped and retained by successive rainy days from late July to early August. These therefore stayed on the midseason rice crops before latter moving to lateseason crops to breed (late August to mid September). It was the 4th generation that migrated back to the south and the 5th generation of residents became victims of the coming winter.