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为获得对Q型烟粉虱Bemisia tabaci(Gennadius)具有高毒力的杀虫真菌菌株并将其应用于生产,采用喷雾法测定了5个球孢白僵菌Beauveria bassiana菌株对烟粉虱若虫的毒力,并运用时间-剂量-死亡率模型分析了B.bassiana 84(Bb84)菌株对烟粉虱若虫的时间效应和剂量效应。结果表明:在5个供试菌株中,Bb84菌株对烟粉虱3龄若虫的致死速度快、致死率最高,逐日死亡率随着Bb84菌株孢子浓度的增加而上升,且其对2、4龄烟粉虱若虫也有较高的毒力。用时间-剂量-死亡率模型分析其剂量效应与时间效应,结果表明:随着Bb84菌株接种时间的延长,相应的致死中浓度(LC50)值随之降低,剂量效应逐渐增强;当Bb84菌株处理浓度为1.0×10~7、1.0×10~8和1.0×10~9孢子/m L时,其对烟粉虱3龄若虫的致死中时间(LT50)值分别为5.44、4.61和4.05 d,即LT50值随菌株孢子浓度的增加而减小,时间效应增强。因此,在实际生产中,当球孢白僵菌Bb84菌株的浓度高于1.0×10~8孢子/m L时,对烟粉虱3龄若虫的防治效果较好。
To obtain an insecticidal fungus strain with high virulence to Bemisia tabaci Q (Gennadius) and to apply it to the production, five strains of Beauveria bassiana against Bemisia tabaci Virulence and analyzed the time and dose effects of B.bassiana 84 (Bb84) against B. tabaci nymphs by using the time-dose-mortality model. The results showed that among the five tested strains, Bb84 strain had the highest lethality and lethality to the 3rd instar nymphs of B. tabaci. The daily mortality increased with the spore concentration of Bb84 strain, Bemisia tabaci also have higher virulence. The time-dose-mortality model was used to analyze the dose-effect and time-effect effects. The results showed that with the prolongation of inoculation time of Bb84 strain, the corresponding lethal medium concentration (LC50) decreased and the dose effect gradually increased. When Bb84 strain was treated The lethal time (LT50) of 3rd instar nymphs of B. tabaci at the concentrations of 1.0 × 10-7, 1.0 × 10-8 and 1.0 × 10-9 spores / m L were 5.44, 4.61 and 4.05 days respectively, That is, the value of LT50 decreases with the increase of the spore concentration of the strain, and the time effect is enhanced. Therefore, in actual production, when the Beauveria bassiana Bb84 strain was higher than 1.0 × 10 ~ 8 spores / m L, the control effect on the 3rd instar nymphs of B. tabaci was better.