短稳杆菌对草地贪夜蛾的杀虫活性及其体内解毒酶的影响

Effects of Empedobacter brevis on insecticidal activity and detoxification enzymes of Spodoptera frugiperda

  • 摘要: 【目的】明确生物农药短稳杆菌对草地贪夜蛾的杀虫活性及其体内解毒酶活性的影响,为草地贪夜蛾的高效绿色防控提供理论依据。【方法】采用叶片浸渍法测定短稳杆菌对草地贪夜蛾1、2和3龄幼虫的室内杀虫活性;通过喷雾法测定短稳杆菌对草地贪夜蛾的田间控制效果;以短稳杆菌亚致死剂量处理草地贪夜蛾幼虫,利用酶标仪检测幼虫体内解毒酶(谷胱甘肽S-转移酶、羧酸酯酶)和乙酰胆碱酯酶活性的变化。【结果】室内杀虫活性测定结果显示,短稳杆菌对草地贪夜蛾幼虫具有较强的毒杀作用,取食经1.00×107孢子/mL短稳杆菌处理的玉米叶片72 h后,1、2和3龄幼虫的校正死亡率分别达86.21%、83.05%和58.33%。玉米田施用100亿孢子/mL短稳杆菌悬浮剂800和1000倍液7 d后,对草地贪夜蛾的防治效果分别为95.84%和93.78%,显著高于0.5%苦参碱水剂800倍液处理(P<0.05),高于200 g/L氯虫苯甲酰胺悬浮剂2000倍液处理但差异不显著(P>0.05)。亚致死剂量短稳杆菌(LC20)处理后,草地贪夜蛾幼虫体内谷胱甘肽S-转移酶、羧酸酯酶和乙酰胆碱酯酶活性均有不同程度下降。【结论】短稳杆菌对草地贪夜蛾低龄幼虫具有较好的室内杀虫活性和田间防治效,可作为防治草地贪夜蛾有效的生物农药使用。在玉米田草地贪夜蛾低龄幼虫盛发期,使用100亿孢子/mL短稳杆菌悬浮剂进行防治时,建议使用800~1000倍液喷施。

     

    Abstract: 【Objective】To investigate effects of Empedobacter brevis on insecticidal activity and detoxification enzymes of Spodoptera frugiperda, so as to provide theoretical basis for its efficient green control.【Method】 Indoor insecticidal activity of E. brevis to S. frugiperda 1st, 2nd and 3rd instar larvae were tested with leaf immersion method. Field control effects of E. brevis to S. frugiperda were carried out using the spray method. The detoxification enzymesglutathione S-transferase(GST) and carboxylesterase(CarE)and acetylcholinesterase(AChE) of S. frugiperda larvae treated with sublethal concentration of E. brevis were detected by the microplate reader.【Result】Indoor insecticidal activity results showed that E. brevis was strongly toxical to S. frugiperda larvae. The adjusted mortality rate of 1st, 2nd and 3rd instar larvae fed on maize leaves treated with 1.00×107 spores/mL E. brevis for 72 h were 86.21%, 83.05% and 58.33%, respectively. In the corn field after spraying 1.0×1010 spores/mL of E. brevis suspension concentrate(SC) at 800 and 1000 times for 7 d, the control effects were 95.84% and 93.78%, significantly higher than that of 0.5% matrine aqueous solutions(SL) (P<0.05) but it had no significant difference with 200 g/L chloranbenzoamide SC(P>0.05). GST, CarE and AChE activity of S. frugiperda larvae were decreased after the sublethal concentration(LC20) of E. brevis treatments.【Conclusion】 E. brevis has strong insecticidal activity and field control effect against larvae of S. frugiperda, and it can be used as an effective biological pesticide for controlling S. frugiperda. It is suggested that 1.0×1010 spores/mL of E. brevis SC at 800 and 1000 times can be sprayed at occurrence period of early-instar S. frugiperda larvae on cornfield to control the damage.

     

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