Department of Vector Biology and Control, Jinan Municipal Center for Disease Control and Prevention, Jinan, Shandong 250021, People's Republic of China.
J Econ Entomol. 2013 Aug;106(4):1825-31. doi: 10.1603/ec12220.
As a selective biological insecticide, spinosad has been used widely for the control of pests including beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae). To form effective pest control strategies, lethal and sublethal effects should be considered for a complete analysis of spinosad impact. However, few studies have been reported to investigate sublethal effects of spinosad on S. exigua. This study attempts to evaluate the lethal and sublethal effects of spinosad on this pest by recording and analyzing various toxicological and physiological parameters. The toxicity of spinosad against S. exigua was determined under laboratory conditions by oral exposure of late second-instar larvae to the compound. The LC50 values of spinosad to S. exigua at 48 and 72 h after treatment were 0.317 and 0.293 mg x kg(-1), respectively. Spinosad at sublethal concentrations significantly extended the developmental period of survivor larvae, and reduced larval wet weight. Postexposure effects were indicated by decreased pupation ratio and pupal weight, by prolonged prepupal and pupal periods and by decreased emergence ratio, fecundity and longevity of adults. The net replacement rate (Ro) tended to be lower in the exposed spinosad groups than those in the unexposed spinosad group. Intrinsic rate of population increase (r(m)) for the high-dose group (0.365) was significantly lower than the control (0.521) and the low-dose group (0.521), but the latter two were not significantly difference. These results suggest that the combination of lethal and sublethal effects of spinosad might affect S. exigua population dynamics significantly by decreasing its survival and reproduction, and by delaying its development.
作为一种选择性生物杀虫剂，多杀菌素已被广泛用于防治包括甜菜夜蛾、斜纹夜蛾（鳞翅目：夜蛾科）在内的害虫。为了制定有效的害虫防治策略，应该考虑致死和亚致死效应，以全面分析多杀菌素的影响。然而，很少有研究报道调查多杀菌素对斜纹夜蛾的亚致死效应。本研究试图通过记录和分析各种毒理学和生理学参数来评估多杀菌素对该害虫的致死和亚致死效应。在实验室条件下，通过口服接触晚期二龄幼虫来测定多杀菌素对斜纹夜蛾的毒性。处理后 48 和 72 小时，多杀菌素对斜纹夜蛾的 LC50 值分别为 0.317 和 0.293 mg x kg(-1)。亚致死浓度的多杀菌素显著延长了存活幼虫的发育周期，并降低了幼虫的湿重。暴露后效应表现为化蛹率和蛹重降低，预蛹期和蛹期延长，成虫的羽化率、繁殖力和寿命降低。净替代率（Ro）在暴露于多杀菌素的组中趋于低于未暴露于多杀菌素的组。高剂量组（0.365）的种群内增长率（r(m)）显著低于对照组（0.521）和低剂量组（0.521），但后两者之间没有显著差异。这些结果表明，多杀菌素的致死和亚致死效应的组合可能通过降低其存活率和繁殖力，以及延迟其发育，对斜纹夜蛾种群动态产生显著影响。
