果洛州玛沁县草原毛虫虫害发生与气候因子的相互关系

利用玛沁县历年草原虫口密度调查资料，研究了气候因子尤其是温度与降水对草原毛虫(Gynaephora alpherakii)虫害发生的影响。结果表明，果洛州玛沁县草原毛虫的灾害严重，危害面积达14.67×104 hm2，1993年最高虫口密度达500头·m-2，2003年也较为严重；1971－2007年的37年间玛沁县的年平均温度呈升高趋势，降水量呈递减趋势；虫口密度与年平均温度、虫口密度与年降水量、虫口密度与年平均温度和年降水量之间均无显著关系（P>0.05）。虫口密度与前一年9月的降水量关系显著（P<0.05），与前一年9月平均温度、降水量二者关系显著，虫害的发生与前一年9月的水热条件密切相关，温度与降水适宜会使草原毛虫大量发生，导致严重虫害。本研究的结果与其他研究分析认为的“温度是草原毛虫生长发育的限制因素”这一结论并不完全一致，这是因为玛沁县近年来温度升高与降水减少，使得温度不再是限制因素，而草原毛虫进行羽化、交配、产卵、孵化所需求的9月降水量成为影响虫害发生的关键因素。

The relationship between damage of grassland caterpillar and climate factors in the Maqin County of Guoluo Prefecture

Based on survey data of population density of grassland caterpillar over the years and temperature and precipitation with long-term observation in the Maqin County,the climatic factors,especially temperature and precipitation,how to influence on the grassland caterpillar was determined in this study by analyzing the relationship between damage of grassland caterpillar and climate factors.The results of this study showed that the grassland area damaged by grassland caterpillar was 14.67×104 ha in the Maqin County of Guoluo Prefecture,and the maximum population density was 500 per square meter,in 1993 and was serious in 2003.From 1971 to 2007,the mean annual temperature of Maqin County showed an increasing trend,and the local precipitation showed a decreasing trend.The correlation analysis results showed that the population density of grassland caterpillar was not related with the average annual temperature,annual precipitation,average annual temperature and annual precipitation,but was significantly related with the precipitation and the average temperature and precipitation in September of the last year,indicating that the occurrence of grassland caterpillar was closely related to water and heat conditions in September of the last year and the appropriate temperature and precipitation encouraged grassland caterpillars to become pest damage.This study did not support the view in which the temperature was the limiting factor to caterpillar life cycle because the increasing temperature and reducing precipitation in recent years in Maqin County made the temperature not be a limiting factor,while the precipitation in September became the a key factor which affected eclosion,copulation and oviposition and incubation in the caterpillar life cycle.