The Study On Migration Origins Of White-backed Planthopper Sogatella Furcifera (Horvath) In Sichuan

The white-backed planthoppers (WBPHs). Sogatella furcifera,which belongs to Homoptera. Delphacidae.are a typical migratory pests in Asian,while is also injurious insect in Sichuan even the national rice region.The long distance journey of Sogatella furcifera to have the Sudden and explosive increases the difficulty of prediction and prevention. The study on the migratory law and source areas of white-backed planthoppers in souetwestem region is very weaker than the eastern half in China.The occurrence of WBPHs bases on the time of action and direct influence of meteorological factors. A better understanding of the temporal and spatial dynamics and migration routes and insect sources of this pest will be beneficial for accurate warning and effective control of this pest in Sichuan and China.The white-baked planthopper, Sogatella furcifera (Horv?th), is a major crop pest in rice production. Recently, it caused serious damage and become serious threat to food safety production in Sichuan. A better understanding of the temporal and spatial dynamics and migration routes and insect sources of this pest will be beneficial for accurate warning and effective control of this pest in Sichuan and China.We analyzed the distribution of the origins and migration pathways of white-backed planthoppers (WBPHs), Sogatella furcifera (Hemiptera; Insecta), in Sichuan, China. The trajectories and distributions of the source areas during the peak days of WBPH migration were simulated and analyzed using HYSPLITY4.8 (Hybrid Single-Particle Lagrangian Integrated Trajectory) and ArcGIS. Additionally, The GrADS (Grid Analysis and Display System), a program for analyzing and displaying the synoptic meteorology background will be used for effects of WBPH migratory meteorological background during the migration periods. This project will provide scientific basis and technical support for accurate warning and effective control of WBPH in Sichuan.The results showed:1 Because of the spatial topography, the WBPHs tended to migrate from southeast to northwest during the beginning and mid-period of the migration.The migration peaks varied at different stations and in different periods. The migration of WBPHs in Sichuan generally peaked in July, whereas the WBPH migrations in southern and eastern Sichuan peaked to a lesser extent in May and June. Overall, the major migration peaks were reduced from southeast to northwest.2 During the early migratory stage (May-June), S. furcifera congregated in the southern and eastern areas of Sichuan. WBPHs from south Sichuan traveled to northern Vietnam and Laos, and to the southeast and northeast of Yunnan Meanwhile,WBPHs sourced from the eastern parts of Sichuan were found south of Chongqing, west of Hu nan, and at the border junction of Hu nan, Hubei, and Chongqing (which partly extends into southwestern Guangxi). In July, influenced by the southwesterly, southerly, and southeasterly winds, the WBPH sources were widely distributed in Yunnan, Guizhou, Chongqing, Guangxi, Hu nan, and Hubei. The main sources in early July were Yunnan, part of mid-western Guangxi, and west of Guizhou. In mid-July, the sources shifted to the northeast, namely, northeastern Yunnan to central Guizhou. Meanwhile, WBPHs originating from south Sichuan may have migrated to central and eastern Sichuan. In late July, WHPHs may have traveled from western to northern Sichuan. At other stations, the source distributions were more average.3 We also found four main migratory paths of WBPHs in Sichuan. The first path extends from west Guizhou to south Sichuan. Under southwest and southerly airflows, the path continues through northeast Guizhou. Chongqing, to east Sichuan. The second path extends from central Guizhou to south Sichuan, or (aided by a southerly wind) through northeast Guizhou, Chongqing to east Sichuan. The third path extends from Hunan, through Chongqing, and to east Sichuan. This path is helped by southeast and southerly air flows. The fourth path extends from Yunnan to west Sichuan under a southerly airflow.4 Taking the Xuyong as example.The study mainly fouces on the the distribution of WBPHs source areas and the meteorological background.The main immigration times of WBPH in Xuyong Sichuan were from May to July. The immigration peaks were few in May. The source areas were mainly located in the southwest of Yunnan, and the secondary source areas were at the central region of Yunnan, the north of Myanmar and Vietnam. In June and July, with The South airflow prevailing in Xuyong,the number of immigration times was increased.The mass immigration of WBPH into Xuyong during June was from the east and south of Yunnan, and some immigrants from the northwest of Guangxi, the north of Myanmar. and the central part of Yunnan. In July, the northeast of Yunnan, the southwestern Guizhou and the border of Yunnan-Guizhou were the major source areas, and the secondary source areas were the central region of Yunnan and the northwest of Guangxi. Based on the analysis on the meteorological background and rainfall distribution, it was found that the rainfall, the vertical movement of airflow and the wind shear caused mass descent of WBPH into Xuyong.5 Applying the ISSR-PCR technology to study the genetic diversity of Sogatella furcifera.The results showed that a total of 171 bands were presented from the 14 selected primers screening across all samples,with the percentage of polymorphic bands up to 88.89%.The result of Pogene revealed quite high level genetic diversity for sogatella furcifera in Sichuan province at the species level(PPB=88.89%, Na=1.8889, Ne= 1.4564, He=0.2796, I=0.4297).The genetic diversity of east Sichuan population was the highest between the different geographic populations and that of west Sichuan population was the lowest.The results of cluster analysis showed that the individuals did not relate to the geographic locations where they were collected,suggesting that the correlation between the Nei's genetic distance and geographical distance was not obvious.The genetic differentiation of geographic populations was lower (Gst=0.1962<0.25),but the gene flow was larger (Nm=2.0479>1).These results could be closely related to the migration of sogatella furcifera,which provides the further experimental basis in order to make sure the migration law of sogatella furcifera in Sichuan region and inscet source relation between each region.