青海云杉种实害虫的防治技术

青海云杉（Picea crassifolakom)种实害虫的优势种为云杉球果小卷蛾（Pseudotomoides strobiiellus)，祁连山区为害严重的林分平均虫果率达81．6％，是防治的主要对象。试验认为：在远离天然林分的地方建立优良性状的无性系种子园，并加强母树林抚育，改造纯林结构，保护利用天敌，增强林分对害虫的自控能力。虫害中等区可利用Bt乳剂100亿孢子／mL质量分数为4％的溶液喷雾和100亿孢子／g的Bt粉剂与滑石粉体积比为1：2混合喷粉防治幼虫。结合采种摘除球果，烧毁残果可杀死果轴内越冬害虫，有效降低虫口，有条件时收集果轴内的寄生蜂释放于母树林，可增加种实害虫天敌寄生蜂。严重危害区可在害虫成虫羽化期采取烟雾剂和树干注药进行化学防治。

Control Technique of the Seed Pests of Picea crassifolakom

The mean vermiculous fruit rate of the dominant specie Pseudotomoides strobiiellus which is the mean target to be controlled, reaches 81.6% in the seriously injured Picea crassifolakom stands of Qilian Mountain. The control measures the authors proposed are as follows: establish superior clone orchards at the areas far away from natural forests, enhense tending of meternal plant stand, transform the structure of pure forests, protect and use natural enemies, strengthen the self-control ability of stands to pests, use 100 billions spore per litter 4% of Bt emulsion solution and Bt powder and talcum powder in the volume ration of 1:2 to spray to control the larva; combined with picking fruit, removing cone and burning the vermiculous fruit can kill the pests who survive the winter in fruit axis, which can effectively decrease the pest number. If the conditions is permitted, collecting the parasitic wasp in the fruit axis to fire to the metrnal plant forest can increase the natural enemies of seed pests. In seriously injured areas, adopting smoke agent or medicine to spray to the trunk in emergence periods can control seed pests.