落叶松叶蜂生物学特性及防治途径研究

A Study on the Biology and Ecology of the Larch Sawfly Pristiphora erichsonii and Its Control

落叶松叶蜂Ｐｒｉｓｔｉｐｈｏｒａｅｒｉｃｈｓｏｎｉｉ（Ｈａｒｔｉｇ）在北京地区１ａ一代，以老熟幼虫在树冠下及周围的枯枝落叶层及松软的土壤中结茧，以预蛹越冬。幼虫群集危害落叶松。卵和幼虫的有效积温分别为１１０．４５８６和３８３．５２５８日度。幼虫发育的最适温度为１６～２０℃。林缘及东南方向比林内及西北方向产卵多，分别为０．７３、０．３块／枝。茧期各种天敌的总寄生率为８３．２３％。以白僵菌、苏云金杆菌、昆虫寄生线虫及敌灭灵进行防治途径研究，结果表明，利用线虫防治室内效果达８０％～１００％，敌灭灵野外效果达９８％～１００％，而白僵菌效果为２８％～５２％，苏云金杆菌的２个亚种效果均不理想，分别为２０．８３％和９．０９５％。

Pristiphora erichsonii(Htg.)has one generation a year in Beijing area with prepupae overwintering in cocoons in the litter and soil under the tree crown. The effective accumulative temperature for the eggs and larvae was studied by means of linear regression method,which were 110. 458 6 and 383. 523 8 day·degree. The optimal developmental tem-perature for larvae ranges from 16～20 ℃. The average number of egg mass per twig is 0.73 at the border of the larch forest or at the western and northern part of the tree,while 0.3 per twig inside the forest or at eastern or southern part of the trees. The parasitic rate of co-coons reached 83. 23%. The effects of abiotic and biotic factors on its occurrence were dis-cussed. According to the results from indoor and field control experiments using Beauveria,B。 t. ,and netomopathogenic nematodes as control agents , it is assumed that the enmatodes are the best biocontrol agents which can infect the larvae on the trees and mature larvae on the ground with a mortality of 80%～100%. The mortality caused by Beauveria and B. t. are 28%～52%and 5%～27%,respectively, with a mortality as high as 98%～100%,Dimilin is also a good insecticide to control the sawfly.