| The white backed planthopper, Sogatella furcifera,is the major crop pest that causes serious damage to rice production. Xing’an, in northeast Guangxi Municipality, is the key annual migratory route for the rice planthopper migrating back and forth between southern and northern China. A better understanding of the population dynamics, population characteristics, migration trajectory and spatial distribution will be beneficial for the monitoring, warning and long-term control of these pest in Xingan and in China. In this study, light traps, systematic field surveys, and dissection of female ovaries were used to study the population population dynamics and population characteristics of this pest. The spatio temporal distribution of source areas of S. furcifera immigration peaks and landing areas of S. furcifera emigration peaks in2011were analyzed using HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory), a software package that simulates migration trajectories, and GrADS (Grid Analysis and Display System), a program for analyzing and displaying the synoptic meteorology background during the migration periods. The spatial distributions of S. furcifera in the field were analysised by traditional spatial analysis method and Geographic Information System. The results were as follows:1. The population dynamics of S. furcifera varied seasonally in Xing’an. S. furcifera had7generations a year, namely the2nd-8th generation. The3rd-6th were the major pestilent generation. Each of the three annual rice crops (early double-crop, middle-season single-crop, and late double-crop) experienced three generations of S. furcifera, with some overlap of S. furcifera generations onto more than one crop. The population density of S. furcifera in the early double-crop rice field was significantly higher than in other two rice fields.2. The sex ratio of S. furcifera in search light trap and Jiaduo light trap were greater than1, but the sex ratio in search light trap was greater than that in Jiaduo light trap. The sex ration of S. furcifera in the three kind of rice fields were all greater than1, but the sex ration in middle-season single-rice was greater than which in the other two rice fields.3. In2011, the first planthopper caught date was6May, while the last planthopper caught was on23October. There were8migration peaks in Xing’an. The immigrate peaks were7-10May,4-18June,27June-8July,1-2August,9-11August,27August-4September. The emigrate peaks were3-5August and8October.4. The early immigrants mainly came from southwest and middle part of GuangXi, some came from north of Vietnam in spring; the back immigrants mainly form middle and east of Hunan and Hubei in autumn. In the early of August, because of the deterioration of nutritional condition in local fields, large number of S. furcifera emigrated northward. The emigrants may arrive at the west of Hunan after9hs flight, and arrive at north of Hunan after24hrs flight. In the early of October, the emigrants may arrive at the middle of Guangxi after24hrs flight, the population can continue fly southward for survive.5. In spring southwest low-level jets carried massive numbers of S. furcifera into Xing’an, while in autumn northeast wind was the main carried flower for the S. furcifera southward migration. Heavy rainfall caused mass descent. S. furcifera always emigrated in no rain day, upward current provide power for the emigration of this pest.6. The spatial distribution of the larva population were mainly aggregation distribution in the fields, Aggregation intensity increased as the population density increased. The aggregation center changed with time. There were lor server aggregation center in field, aggregation area at west-east direction was longer than north-south direction. |
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