湿地松林越冬代马尾松毛虫死亡因子考察

<正>马尾松毛虫(Dendrolimus punctatus Walker)是我国马尾松林危害最严重、分布最广泛的食叶害虫。为了预测这种害虫的发生数量和进行综合防治,我们采用生命表的方法,在浙江省余杭县长乐林场对湿地松林马尾松毛虫的各种死亡因子进行了系统的考察,分析了影响数量变动的各个因子的作用。本文报道的是1979年～1982年对越冬代松毛虫的研究结果,其它各代的考查材料将陆续整理成文。 马尾松毛虫在浙江余杭县一年发生2～3代,第一代发生期5月中旬～7月下旬,第二代7月下旬～10月上旬,第三代10月上旬到下一年的5月中旬。发生2代的年份,即第二代发育到下一年的5月中旬结束。马尾松毛虫以四龄幼虫越冬为主。这种害虫除危害马尾松(Pinus massoniana Lamb.)外,也取食湿地松(Pinus elliottii Engelm.)和火炬松(Pinus taeda L.)。

STUDIES ON FATAL FACTORS OF THE PINE-MOTH IN THE WINTER GENERATION AT THE FOREST OF SLASH PINE

The fatal factors of the winter generation pine-moth, D. punctalus Walker were observed on Chang Le Forest Farm of Zhejiang Province during 1979?982. The results are as follows. The larval stage has the highest death rate, mainly in the first and fourth larval stadiums, when the death rates are 30.4% and 39.3% respectively. It is caused by climatic conditions, i. e. changes of wind, rainfall and temperature. The main fatal factor for pine-moth D. punctatus walker at later larval stadiums is the predation of birds, particularly when the degree of density is low. Since Slash pine (pinus elliottii) has a rather high resistance to pine-moth, the death rate in the early larval stadiums is high and the unmber of female wackers and the quantity of eggs are reduced.