内蒙古落叶松球果花蝇的危害预测

THE FORECAST OF THE DAMAGE OF LARCH CONE FLIES IN INNER MONGOLIA

1988年6月末至7月初,在内蒙古大兴安岭乌尔旗汗的兴安落叶松人工林、天然母树林内,对危害落叶松球果的花蝇进行了危害调查,球果受害率天然林为97.0％,人工林为99.3％,种子受害率各为73.2％、82.5％。经调查数据及各生境因子进行数量化多元分析,其结果表明:在不同的生境内,花蝇的危害率不同。花蝇对生境条件的要求具有双重性,即在大范围内需较高的温度,在小范围内需要温度低、湿度大的生境。花蝇发育的理想生境:南坡上坡位、郁闭度大、树冠中部北侧、林内或林缘。

The damage of larch cone flies (Strobilomyia spp.)were surveyed in matural and artificial larch forests in Wurjihan of Inner Mongolia in the summer in 1988,-and the larch cone infestation rate in natural forest is 97.0%,in artificial forest is 99.3%,and the seed infestation rates are 73.2%,82.5% respectively. The result of quantative multiply regression analysis based on the investigated data and habitat factots shows that the infestation rates of the cone flies are different in different habitats and the cone flies have double demands for the habitat conditions;they demand the habitat with higher temperature in large range and smaller temperature variations and higher humidity in small range. The ideal habitat most suitable for the growth and development of the cone flies is the combination of the following factors:the upper part of south slope, high crowm density,the middle part in the morth side of crown and in forest or forest edge.