温带气旋对一代粘虫迁飞的影响:2015年个例分析

【目的】一代粘虫Mythimna separate(Walker)蛾大多在5月中旬至6月中旬集群外迁,而此时我国温带气旋活动较为频繁,由气旋活动引起的风场条件的变化会对一代粘虫的迁入区分布造成极大影响,因此阐明温带气旋对一代粘虫迁飞过程的影响是预测2代粘虫发生的重要前提。【方法】通过在江苏姜堰、安徽金安和山东宁津设立高空灯监测点,获取三地粘虫空中种群过境动态,结合WRF(Weather Research and Forecast)模式输出的精细风温场资料分析2015年温带气旋对一代粘虫迁飞的影响。【结果】2015年5月东亚反气旋频繁过境,一代粘虫在反气旋影响下多往西南和西北方向迁飞。6月上旬在东北低涡和蒙古气旋的影响下,一代粘虫可迁入东北地区为害。【结论】春夏之交频发的温带气旋是导致我国二代粘虫大范围为害的重要原因。

The influence of an extratropical cyclone on the first generation of Mythimna separata (Walker) migration:A case study in 2015

Objectives] To investigate the degree to which the migration of first generation armyworm, Mythimna separata, populations are affected by the extraordinary wind fields generated by frequent extratropical cyclones in the period from mid-May to mid-June in China. Determining how extratropical cyclones influence the migration of first generation armyworms is an important prerequisite for predicting outbreaks of the second generation. [Methods] High altitude light traps and elaborate wind-temperature field data (simulated by a WRF model) were used to monitor the population dynamics of first generation armyworm moths flying past Jiangyan, Jin’an and Ningjin (in Jiangsu, Anhui and Shangdong Provinces, respectively) and determine how extratropical cyclones affected the migration in 2015. [Results] Owing to the high frequency of anticyclones in East Asia in May, 2015, first generation armyworms mainly migrated southwest and southeast. A northeast cyclonic vortex and Mongolian cyclone in early June, 2015 may have been responsible for outbreaks of first generation armyworms in northeast China that caused significant damage to crop production there. [Conclusion] Extratropical cyclones are an important cause of large-scale outbreaks of second generation armyworms in China at the end of spring and the beginning of summer.