2008年桂北地区稻飞虱特大迁入事件分析

2008年5月下旬—6月中旬,桂北地区出现了褐飞虱Nilaparvata lugens（Stl）和白背飞虱Sogatella furcifera（Horváth）特大迁入峰,单晚单灯虫量超百万。如此大量的迁入虫源究竟来自何方？利用HYSPLIT轨迹分析平台、地理信息系统ArcGIS和气象图形软件GrADS,对稻飞虱的特大迁入峰及其大气背景场的个例分析表明：（1）西南方向的低空急流为广西稻飞虱大规模迁入提供了运载气流,降雨是迫使稻飞虱集中降落的主要原因;（2）5月下旬,虫源地主要分布在越南北部地区（20°～22°N）,6月上旬,虫源地主要分布在越南东北部地区（21°～23°N）,6月中旬桂西北地区大规模迁入的虫源地位于越南东北部、广西西南部,桂东北虫源地分布在广西东南部;（3）虫源地的空间分布和虫源基数的差异直接导致了6月中旬桂东北和桂西北地区降虫量的巨大差异。

Anylysis of the unusual immigration of rice planthoppers in northern Guangxi in 2008

A huge immigration peak（more than one million captures in a single light trap in one night） of rice planthoppers（RPH）,including the brown planthopper,Nilaparvata lugens（Stl） and the white backed planthopper,Sogatella furcifera（Horváth） occurred in northern Guangxi Municipality from late May to mid June 2008.Where did these insects come from？ The RPH immigration process and the atmospheric conditions that influenced the insects＇ settlement process were analyzed with HYSPLIT,a trajectory analysis software that simulates migration trajectories,GIS（Geographic Information System）and GrADS（Grid Analysis and Display System）.The results were as follows：（1）Airborne RPH populations were carried by a strong,low-level,southwest jet-stream and the mass migration into Guangxi was caused by extensive heavy rainfall in northern Guangxi during late May to mid June.（2）Most of the immigrants were tracked to northern Vietnam（20°-22°N）in late May,and to northeastern Vietnam（21°-23°N）in early June.The mass immigration of RPH into north-western Guangxi during mid June was found to have originated in northeastern Vietnam and southwestern Guangxi,but the insects that migrated to northeastern Guangxi at the same time came from southeastern Guangxi.（3）The significant difference in number of migrants between northwestern and northeastern Guangxi was caused by variation in spatial distribution and population density in their respective source areas.