摘要
[ Objective] The paper was to study pathogenic mechanism and action mode of Bacillus thuringiensis （Bt） 00-50-5 strain against Trichoplusia ni Hub- ner. [Method] The crystals and spores of B. thuringiensis 00-50-5 strain were first isolated and purified, and their insecticidal activities against T. ni were com- pared. [ Result] Either the mixture of pure crystals and pure spores of 00-50-5 strain, or only pure crystals could kill T. n/larvae under the concentration of 100 p.g/mL after 48 h, and the mortality rate reached 100% ; pure spores could not kill the larvae. Determination results of median lethal concentration showed that in- secticidal activity of pure crystal of Bt 00-50-5 strain （LGs0 =0.32 p~/mL） was higher than the mixture of crystals and spores （LCs0 =0.48）, but the insecticidal acti^ty of pure spores was very low （LC50 〉 500.00）. Therefore, the crystals were primarily responsible for causing death of larvae. [ Conclusion] The paper provides theoretical basis for application of Bt 00-50-5 strain.
[ Objective] The paper was to study pathogenic mechanism and action mode of Bacillus thuringiensis （Bt） 00-50-5 strain against Trichoplusia ni Hub- ner. [Method] The crystals and spores of B. thuringiensis 00-50-5 strain were first isolated and purified, and their insecticidal activities against T. ni were com- pared. [ Result] Either the mixture of pure crystals and pure spores of 00-50-5 strain, or only pure crystals could kill T. n/larvae under the concentration of 100 p.g/mL after 48 h, and the mortality rate reached 100% ; pure spores could not kill the larvae. Determination results of median lethal concentration showed that in- secticidal activity of pure crystal of Bt 00-50-5 strain （LGs0 =0.32 p~/mL） was higher than the mixture of crystals and spores （LCs0 =0.48）, but the insecticidal acti^ty of pure spores was very low （LC50 〉 500.00）. Therefore, the crystals were primarily responsible for causing death of larvae. [ Conclusion] The paper provides theoretical basis for application of Bt 00-50-5 strain.
基金
supported by Project for Introduced Talents in Environment and Plant Protection Institute of Chinese Academy of Tropical Agriculture(HZS1101)
Fundamental Research Special Project for Central Public-interest Scientific Institutes(2012hzs1 J038,2012hzs1 J016)
