From April to May, 1990-2012, the source areas of early immigration of white鄄backed planthoppers Sogatella furcifera (Horv佗th) (WBPH) were studied through the analysis on the daily light鄄trap catches, immigration trajectory simulation and horizontal wind field. The following results were obtained: The high frequency of westerly wind carried the large population of WBPH to Shizong in late April. The source areas were mainly located in northeastern Myanmar and the secondary source areas were at northern Vietnam and Golden Triangle. Airborne WBPH populations were carried by a strong, low鄄level, southwest jet鄄stream in May and the mass immigration of WBPH into Shizong during early and middle May was found form northern Laos, northwestern Vietnam and Southwestern Yunnan, and some immigrants from northeastern Myanmar. Most of the immigrants in late May were tracked to Southwestern Yunnan, and part of immigrants to northwestern Vietnam, northern Laos and northeastern Myanmar. Based on the analysis on the meteorological background and rainfall distribution, it was found that the extensive heavy rainfall in southeastern Yunnan during late April to May and http: / / www.ecologica.cn low temperature shield of surrounding to flying WBPH and the wind shear associated with heavy precipitation were the key factors to affect the concentrated landing of WBPH.

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