2021年我国草地螟发生特点与原因分析

Occurrence characteristics and causes of meadow moth Loxostege sticticalis outbreaks in China in 2021

【目的】草地螟Loxostege sticticalis是我国北方重要的迁飞性害虫,对我国华北、东北、西北农牧交错区安全生产造成严重威胁。明确草地螟年度间发生特点、发生原因,可以为今后开展监测预警和防控防治提供重要的理论依据。【方法】在华北、西北和东北等草地螟常发区,利用高空测报灯和常规测报灯监测成虫始见期、发生盛期、蛾峰日及其发生数量;人工踏查法调查成虫和幼虫发生田块和虫口密度,估算其发生面积,分析我国北方草地螟时空发生动态。【结果】2021年我国草地螟成虫发生区域广,在内蒙古大部分地区、河北和山西北部等地灯下蛾峰多、蛾量高,内蒙古大部分地区和河北张家口等地田间越冬代成虫数量高,一代幼虫在内蒙古大部地区和山西北部多地见高密度点。【结论】分析认为,部分区域越冬虫源基数偏高是2021年我国草地螟在内蒙古及其周边地区中等发生的主要原因,春季气温偏高导致大部地区越冬代成虫始见期偏早,内蒙古中西部及其周边地区适宜的降水和温度是草地螟幼虫发生较重的关键,风场条件是导致灯下蛾峰次数多且时空集中的重要因素,内蒙古及其周边境内外虫源存在源库关系。

[Objectives]The meadow moth Loxostege sticticalis is an important migratory pest in northern China, which poses a serious threat to the production safety in the agricultural and pastoral intercropping areas in north, northeast and northwest China. Clarifying the characteristics and causes of the annual occurrence of the L. sticticalis can provide an important theoretical basis for early monitoring, prevention and control in the future. [Methods]In north, northwest and northeast China, first appearance date, occurrence peak, moth data and occurrence number of the adults were monitored by pest monitoring lamps and high altitude lamps. Adult and larval field population densities were investigated by artificial field survey, and the occurrence area was estimated to analyze the temporal and spatial dynamics of the L. sticticalis. [Results]The meadow moth, L. sticticalis, occurred in many parts of China in 2021. Most of Inner Mongolia, northern Hebei and Shanxi had frequent peaks of meadow moth abundance and most of Inner Mongolia and Zhangjiakou in Hebei had high numbers of overwintering adults. First generation of larvae were mostly observed in Inner Mongolia and northern Shanxi. [Conclution]A high number of overwintering adults was the main reason for the moderate meadow moth abundance in Inner Mongolia and surrounding areas in 2021. The high spring temperature that year resulted in an earlier overwintering adult generation in most areas. Furthermore, suitable precipitation and temperature in central and western Inner Mongolia and surrounding areas were key factors leading to outbreaks of L. sticticalis larvae. Favorable wind conditions are also an important factor affecting the number of population peaks and the distribution of this pest in space and time. L. sticticalis populations in Inner Mongolia and surrounding areas are sources of immigrant moths for local migrations within this region.