杀虫剂螨危的亚致死剂量对朱砂叶螨种群参数的影响

Effects of Sublethal Dose of Spirodiclofen on the Population Parameters of Tetranychus cinnabarinus Boisduval

朱砂叶螨是桑树的主要害虫之一。从避免过度使用农药造成环境污染和控制害螨的抗性发展的角度,研究了杀虫剂螨危的亚致死剂量对朱砂叶螨敏感种群生存与繁殖能力的影响。分别用质量浓度为1.25、2.5、5、10、40 mg/L的螨危药液处理雌成螨,48 h后的存活率分别为96%、83%、81%、75%、48%;药液对雌成螨和卵的致死中浓度(LC50)分别是35.005 mg/L和0.690 mg/L,卵的敏感性明显高于雌成螨。与对照组相比,随螨危药液处理浓度增高,雌成螨的7 d总产卵量和孵化率呈下降趋势;用10、5、2.5、1.25 mg/L药液处理后朱砂叶螨种群的瞬时增长率(ri)分别是-0.083、0.142、0.214、0.298,而对照组为0.544,有效中浓度(EC50)值为1.627 mg/L。研究结果表明,用低于推荐使用浓度(40 mg/L)的螨危药液就能有效控制朱砂叶螨种群的增长。

Tetranychus cinnabarinus Boisduval is one of the major mulberry pests.In order to avoid excess usage of pesticides which could cause environmental pollution and resistance of the pests,we investigated the effects of sublethal dose of spirodiclofen on survival and reproduction of the susceptible T.cinnabarinus Boisduval population.48 h after the treatment with 1.25,2.5,5,10,and 40 mg/L spirodiclofen solutions,survival rate of the treated adult females was 96%,83%,81%,75% and 48%,respectively.The median lethal concentration（LC50） of adult females and eggs was 35.005 and 0.690 mg/L respectively.The susceptibility of eggs was significantly higher than that of adult females.Compared to the controls,7-day total fecundity of the females and hatching rate of the eggs decreased as concentration of spirodiclofen increased.After being treated with 10,5,2.5 and 1.25 mg/L spirodiclofen solutions,the instantaneous rate of increase（ri） was-0.083,0.142,0.214 and 0.298 respectively,while that of the control was 0.544.The median effective concentration（EC50） was 1.627 mg/L.The results indicated that using spirodiclofen at concentrations lower than the recommended one（40 mg/L） could already control the increase of T.cinnabarinus Boisduval population effectively.