噻虫嗪对白背飞虱试验种群繁殖力的亚致死效应

为探究噻虫嗪对白背飞虱的亚致死效应,采用稻茎浸渍法以噻虫嗪亚致死浓度LC_(10)和LC_(25)胁迫白背飞虱3龄若虫,测定了F_0代和F_1代若虫的存活率、雌成虫寿命和产卵量,并组建了F_1代种群相对适合度生命表。结果表明,经噻虫嗪亚致死浓度胁迫后,F_0代白背飞虱若虫的发育历期延长,存活率降低,并且LC_(10)处理组的F_0代雌成虫寿命比对照组显著延长,而成虫产卵量无显著变化;F_1代的若虫发育历期比对照组显著延长,且产卵量有所减少,LC_(10)处理组雌成虫产卵量比对照组减少了22.24,LC_(25)处理组比对照组减少了69.96,且差异显著;LC_(10)和LC_(25)亚致死浓度处理后F_1代的种群增长趋势指数均下降,种群相对适合度分别下降了0.12和0.36。研究表明,噻虫嗪亚致死浓度胁迫均可抑制白背飞虱的种群增长。

Sublethal effects of thiamethoxam on the fecundity of lab populations of white-backed planthopper Sogatella furcifera(Horváth)

To figure out the sublethal effects of thiamethoxam on white-backed planthopper Sogatella furcifera(Horváth),the 3rd instar nymphs were exposed to the two sublethal doses LC₁₀ and LC₂₅ of thiamethoxam with the rice stem dipping method.The survival rates of F₀ and F₁ nymphs,the longevity and fecundity of F₀ and F₁ adults were investigated.The life-table of F₁ generation was constructed.The results showed that both sublethal doses could prolong the developmental duration and decrease the survival rate of F₀ nymphs.In addition,F₀ female adults treated by LC₁₀ of thiamethoxam had significant longer lifespan compared to that of the control,and the fecundity of adults had no difference from that of the control.As for F₁ generation,both treatments significantly prolonged the developmental durations of nymphs.The oviposition amount of adults treated with LC₁₀ of thiamethoxam was 22.24 eggs less than that of the control,while that of the adults treated with LC₂₅ of thiamethoxam was significantly 69.96 eggs less than that of the control.Both sublethal doses of thiamethoxam resulted in declining population trend index.The relative fitness of F₁ generation treated by LC₁₀ and LC₂₅ of thiamethoxam was reduced by 0.12 and 0.36,respectively.The results indicated that the sublethal dose of thiamethoxam had negative effect on S.furcifera.