首次入侵广东的草地贪夜蛾迁入路径及天气背景分析

草地贪夜蛾 Spodoptera frugiperda (J. E. Smith)是联合国粮农组织全球预警的超级害虫,2019年1月入侵我国云南,并随季风远距离迁飞扩散,4月23日,广东省广州市增城区首次发现并确认该虫幼虫发生为害,对当地玉米等粮食作物构成严重威胁。本研究运用基于WRF模式的昆虫三维轨迹分析程序和GrADS气象图形软件,模拟了入侵广东的草地贪夜蛾的迁飞路径及天气背景场。结果表明:按照幼虫发育历期推算,首批草地贪夜蛾成虫迁入广东的时间可能为4月8日~13日;在此期间,越南北部及华南地区的西南低空急流可为草地贪夜蛾的迁飞提供运载气流,而风切变、降雨和下沉气流为草地贪夜蛾的迫降提供便利条件;4月9-10日存在草地贪夜蛾的有效迁飞路径,入侵广东省增城区草地贪夜蛾种群的有效虫源地分布在越南及老挝北部。本研究为华南地区草地贪夜蛾春季迁入种群的监测预警及防控提供了科学依据。

Analysis of migratory routes and atmospheric features of the newly invaded fall armyworm, Spodoptera frugiperda (J.E.Smith) in Guangdong Province

The fall armyworm, Spodoptera frugiperda(J.E.Smith), is an extremely destructive agricultural pest worldwide, which has been warned by the United Nations'' Food and Agriculture Organization (FAO) since 2016.It first invaded the southwestern part of Yunnan Province, China in January 2019, and thereafter immigrated or spread to South China as the southwestern monsoon blows in spring.It is reported for the first time that a great number of larvae of the fall armyworm were present in the corn field in Guangzhou City''s Zengcheng district, Guangdong Province on April 23th, 2019.It will pose a serious threat and damage to crop production, especially to maize production in Guangdong Province.The migratory routes and weather fields for the case of the newly invaded fall armyworm in Guangdong Province were simulated by using Weather Research and Forecast (WRF) Model and Grid Analysis and Display System (GrADS), combined with reanalyzed meteorological data from the National Center of Environment Predicting (NCEP) of the USA. The results showed that according to the development period of larvae, the first invaded adult population of the fall armyworm might immigrate to Guangdong Province from April 8th to April 13th, 2019. During this period, southwest of strong low level jet between northern Vietnam and South China carried migratory populations of the fall armyworm into Guangdong Province. The landing populations of the fall armyworm were caused by wind shear, rainfall and downward flow.The effective migratory of the fall armyworm took place on April 9th and April 10th, 2019. Simulations of migration trajectories indicated that the immigrants of the fall armyworm in Zengcheng district came from Northern Vietnam and Northern Laos.This study provided a scientific basis for monitoring, early warning and control of spring migratory populations of the fall armyworm in South China.