【摘要】 1981～1982年试验结果表明,HD-1菌剂对稻纵卷叶螟的防治效果为70～82%,并对后代发生数量有一定影响。一般以卵盛孵末期到2龄幼虫发生初期,每亩每次用 HD-1菌剂150克防治两次为宜。室内毒力测定:HD-1菌粉（芽孢与晶体比例为1:1.05）和晶体对稻纵卷叶螟的毒力高,芽孢毒力低。HD-1菌粉处理2龄和3龄幼虫的 LC₅₀,活孢子数分别为3.16×10⁶个/毫升和3.16×10⁷个/毫升。HD-1菌粉（含活孢子数7×10⁷个/毫升）对2龄幼虫的 LT₅₀,在平均24.6℃下,为15.84小时。HD-1处理后的卵能正常孵化,但能引起初孵幼虫的死亡;5龄老熟幼虫,部分能带毒进入蛹期,引起蛹的死亡。HD-1不杀伤天敌,HD-1防治区的天敌总数、种类比化防区多,天敌增长率也高于化防区。稻田施用 HD-1,能有效地降低土壤、稻谷中化学农药残留量。更多还原

【Abstract】 Field tests in Chnagsha from 1981 to 1982 showed that the efficiency of Bacillus thuringiensis var.Kurstaki （HD-1） in controlling the rice leaf roller,Cnaphalocrocis medinalis （Guenee’） was 70～80%,and that HD-1 also reduced the population of the later generations.In general,HD-1 formulation would better be used at the time from the late oviposition period to the early appearance of 2nd-instar larvae.The suitable usage of HD-1 formulation was 150g/mu each time.Two applications were ncce- ssary. Laboratory assay demonstrated that the toxicity of the powder HD-1 （The proportiom for its sporesis and crystals is 1:1.05） and crystals were higher than that of its spores.LC₅₀ of the powder HD-1 treat- ment for 2nd instar larvae was 3.16x10⁶ spores/ml,and for 3rd,3.16×10⁷ spores/ml.LT₅₀ of the powder HD-1 （7×10⁷ spores/ml） treatment for 2nd-instar larvae,at an average temperature of 24.6℃,was 15.84 hrs. Eggs could normally hatch after treatment,but HD-1 could cause the death of the newly hatched larvae.The 5th-instar larvae bearing patho- genes could cause the death of pupae. This bacterium did no harm to the natural enemies,which were found to be more in the area where HD-1 was applied than those in the area where chemical insecticides were used,and the increasing rate of natural enemies was higher,too. The use of HD-1 can alse reduce the chemical residues in the soil and rice grains.更多还原