2020年我国北方地区草地螟种群的时空动态与虫源分析

Spatiotemporal Dynamics and Source of Loxostege sticticalis in Northern China in 2020

【目的】研究2020年草地螟(Loxostege sticticalis)在我国北方地区季节性时空动态,并对各主要发生区的虫源性质进行分析,探讨草地螟在我国华北、东北地区,境内、境外的虫源衔接关系,为提高草地螟预测预报水平提供技术支持。【方法】利用北京、天津、河北、内蒙古、辽宁、山西相关植保站探照灯诱虫器或虫情测报灯的虫情数据,分析草地螟在我国北方地区种群数量的时空动态变化。通过GrADS软件对FNL全球分析资料进行处理,获得高峰期内主要蛾峰日的风场数据并绘制风场图。采用基于WRF模式编写的三维质点轨迹分析程序对草地螟迁飞路线进行模拟,利用R 3.8的ggplot23.3.0程序包对轨迹模拟结果进行绘图。【结果】2020年越冬代草地螟成虫主要发生在山西、河北北部,内蒙古中西部和兴安盟地区;1代草地螟成虫大量突增主要集中在内蒙古化德县和与之接壤的河北康保县。风场分析显示,在草地螟典型的迁飞期内,华北及东北地区均受到锋面和气旋过程的影响;东北气旋前部的偏南或西南低空急流为华北越冬区的草地螟远距离迁入东北提供了有利条件,其后部的西北气流则会阻碍草地螟向东北的迁飞。虫源分析显示,华北地区越冬代成虫大部分滞留当地危害,部分借助适宜的西南气流向东北地区及中蒙、中俄三国交界迁飞;内蒙古兴安盟地区5月下旬虫源主要来自草地螟华北越冬区,6月上旬部分来自华北越冬区,部分来自中蒙、中俄三国交界处,6月下旬主要来自华北越冬区迁出虫源。1代草地螟成虫主要来自内蒙古中西部及中蒙边界1代幼虫发生区,受锋面天气影响在内蒙古化德县和河北康保县聚集降落,并进一步向东北方向迁飞扩散。【结论】2020年是草地螟2018年种群回升以来又一重发年份;气旋天气形成的强劲气流是华北地区和境外虫源顺利进入东北地区的主要运载气流,风切变、气旋中心等气流的辐合使大面积迁飞的成虫聚集降落,造成局部虫量突增;我国华北和东北地区草地螟越冬代和1代成虫均与境外虫源存在频繁的交流,因此,开展草地螟区域性联合监测对草地螟的异地测报具有重要的指导意义。

【Objective】To provide supports for improving the monitoring and warning level of the beet webworm,Loxostege sticticalis,the seasonal spatiotemporal distribution in Northern China,the sources and relationship between L.sticticalis in North and Northeast China,within and outside China were studied in 2020.【Method】The searchlight traps were assembled to daily monitoring in Beijing,Tianjin,Hebei,Liaoning,Shanxi and Inner Mongolia.Based on the monitoring data of searchlight traps at the plant protection stations in the 6 provinces(municipality,Autonomous Region),the population fluctuations and migration pattern of L.sticticalis in Northern China were analyzed by using GrADS and R.The FNL data were processed by GrADS software,to obtain wind field information and draw the map.A three-dimensional particle trajectory analysis program based on WRF model was used to simulate the migration route of L.sticticalis,and the trajectory simulation results were plotted by ggplot23.3.0 package of R3.8.【Result】The overwintering generation of L.sticticalis adults mainly occurred in Shanxi,Hebei and Inner Mongolia,and a large number of adults of the 1st generation were found in Huade of Inner Mongolia and Kangbao of Hebei in 2020.During the typical migration period,North China and Northeast China were affected by frontal and cyclonic processes.The southward or southwest low-level jet at the front of the northeast cyclone provided favorable conditions for the long-distance migration of L.sticticalis into the northeast region,but the northwest airflow at the back of it blocked the migration path.The results showed that most of the overwintering adults stayed in North China and some of them migrated to Northeast China and the border of China,Mongolia and Russia with the help of southwest airflow.In late May,the main source in Hinggan League of Inner Mongolia came from the overwintering area of L.sticticalis in North China.In early June,part of them came from the overwintering area of North China,part of them came from the junction of China,Mongolia and Russia.In late June,the main source came from North China.The adults of the 1st generation of L.sticticalis mainly came from the 1st generation larva occurrence areas in central and western Inner Mongolia and the border between China and Mongolia.Affected by the frontal weather,they gathered and landed in Huade of Inner Mongolia and Kangbao of Hebei,and further migrated to the northeast.【Conclusion】2020 is a typical year of outbreak since the population of L.sticticalis has risen again in 2018.Strong air currents are important reasons for its successful migration,the convergence of wind shear and cyclone center causes the migrating adults to gather and land in large area,resulting in a sudden increase of local insect population.Both the overwintering generation and the 1st generation of L.sticticalis in North China and Northeast China were closely related to the foreign sources.It is of great significance to carry out the regional monitoring and prediction and forecasting in advance for L.sticticalis.