Influence of synergism with Bacillus thuringiensis and Beauveria bassiana on diamondback moth larvae

摘要

[Objective] Researching the effects of different concentrations of B. thuringiensis and B. bassiana mixed liquor on the mortality of Plutella xylostella larvae in Jiamusi. [Methods] Employing PBS buffer diluted the B. thuringiensis and B. bassiana into different concentrations of suspension, the mixture of B. thuringiensis and B. bassiana was mixed into seven different concentration gradients by orthogonal analysist, and determination the mortality of P. xylostella larvae at different concentrations, and then screened more suitable larval LD50 proportion and concentration. [Results] According to the observation and analysis, when the ratio of B. thuringiensis and B. bassiana was 3: 1 in 96h, the P. xylostella larvae mortality rate reached 72%, among them, the median lethal rate of larvae in 10~(-1)～10~(-6) g/mL was higher. [Conclusion] The lethal effect of each mixture on the diamondback moth larvae was different. When the mixture ratio of B. thuringiensis and B. bassiana was 3: 1 and the concentration was 10~(-1)～10~(-6)g/mL, the lethal effect on insect larvae was obvious.