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一、生长习性松毛虫每年发生2-3代,以幼虫多在树冠顶端松针丛中,也有在树干的树皮裂缝内越冬,次年2月中、下旬越冬幼虫开始活动取食,一般蜕皮2次后,于4月下旬结茧化蛹,5月中旬羽化产卵,5月下旬第1代幼虫孵化,7月中旬化蛹,7月下旬羽化产卵,8月上旬孵化出第2代幼虫,到8月中、下旬,第2代幼虫开始分化:一部分第2代幼虫正常地于9月上旬结茧化蛹,9月下旬羽化产卵,10月上旬孵出第3代幼虫,第3代幼虫于11月上旬停止越冬;另一部分第2代幼虫于8月中下旬进入滞育,生长发育缓慢,延续至11月越冬。1、2龄幼虫受惊吓吐丝下垂并可借风传播;3、4龄幼虫分散危害,啃食整个针叶,遇惊坠落;5、6龄幼虫有迁移习性,在林间爬行。
First, the growth habit of pine caterpillars occur 2-3 generations a year to more larvae pine needle plexus at the top of the canopy, but also in the tree bark cracks in the trunk of the winter the following year in mid-February, late wintering larvae began feeding activities, the general molting 2 After the second cocoon pupation in late April, emergence of oviposition in mid-May, the first generation of larvae hatch in late May, pupae in mid-July, emergence of oviposition in late July, early August hatched second-generation larvae In the middle and late August, the 2nd generation larvae began to differentiate: some of the 2nd generation larvae normally cocoon pupation in early September, and oviposited in late September, third generation larvae in early October, The larvae stopped overwintering in early November; the other part of the second-generation larva entered diapause in late August and grew slowly, extending to wintering in November. The first and second larvae were scared by silkworms and could be spread by wind. The 3rd and 4th instar larvae were scattered and damaged, they gnawed the whole conifer and fell in shock. The 5th and 5th instar larvae migrated and crawled in the forest.