黑龙江省草地螟第三个暴发周期特点及成因分析

Analysis on characteristics and causes of meadow webworm,Loxostege sticticalis,in the third outbreak cycle in Heilongjiang.

草地螟Loxostege sticticalis L．是我国北方农牧区重要突发性害虫，黑龙江省是主要迁入危害区，自1996年进入第3个暴发周期后，每年均有不同程度发生危害，该周期比上一周期发生时间提前5～7d，周期持续时间也延长了5年。此周期内该省草地螟累计发生面积近1333万hm^2次，比上个周期增加了近800万hm^2，草地螟1代幼虫密度最高达每m^2 10000头以上，尤其2004年在该省大范围内达到特大发生，有13个县（市）田间百步惊蛾达到万头以上，个别高达50000头以h 。作者根据这一周期草地螟发生实况，分析了草地螟种群暴发与气候条件变暖的关系，包括天气、湿度、种植结构、天敌等因素的影响，为草地螟综合治理提供依据。

Meadow webworm（ Loxostege sticticalis L. ） is an important and exploding pest in farming and stockbreeding areas of northern China. Heilongjiang Province is one of the main immigrant regions. Meadow webworm had come into it＇ s third outbreak cycle since 1996, the larvae population density of first generation was more than 10 000/m^2 , and the cumulative areas of damaged grassland reached 1 300 million hm^2 which was increased about 800 million hm^2 than that of the second outbreak cycle. The peak time was earlier 5 ～ 7 days and cycle duration was prolonged 5 years of the third outbreak cycle compared to the pre two outbreak cycles. Especially the webworm extra severely occurred in wide area of Heilongjiang province in 2004, the adult population density was higher up to 10 000 or 50 000/100 paces in 13 counties. According to analysis on characteristics of the third cycle, we knew that the outbreak of the meadow webworm was closely correlated with climate warming, weather action, temperature and moisture in June, plant structure and natural enemy factors, etc. The result offered theoretical basis for deeply comprehending integrated management of meadow webworms.