【摘要】 本文系应用苏云金杆菌(Bacillus thuringiensis var.thuringiensis)粉制剂防治马尾松毛虫(Dendrolimus Punctatus Walk.)的试验结果,试验表明此菌的致病力高,防治效果好,大有应用的前途。应用时,菌剂的浓度应随幼虫龄期的增加而递增,含孢子数的有效幅度为1,500-27,000万/c.c.死亡率可达90-100％。此菌如与稀浓度化学药剂(如666、DDT、敌百虫)混合使用,防治抵抗力较强的4-7龄幼虫,效果更好。更多还原

【Abstract】 The pine caterpillar is one of the most important pests of pine trees in China. Be-cause there are some disadvantages to apply chemical control of this pest, an urgentneed of using microbial methods as a supplementary measure is evident. The results ofthe preliminary test are very promising. The results are as follows: 1. The application of B. thuringiensis var. thuringiensis to control the pine cater-pillar seems to be very effective. In future it may develop into a new and powerfulweapon in pest control work. 2. The concentrations of the bacterial suspensions should be raised with the in-crease of larval instars. The range is approximately between 15×10~6--2.7×10~8 sporesper c.c. 3. High temperature resulted in a quick infection and death of the larvae. There-fore, the application of this method in June, July and August will give better results,though in cold and wet seasons, for example in March and April in central China, thecontrol is also effective. 4. The applications of B. thuringiensis var. thuringiensis with very dilute concentra-tions of chemical insecticides, such as 666, DDT and Diptrex, will give quicker andbetter results. This is a promising method. Dusting is valuelessly.更多还原