Phytoinsecticides are considered as an effective and environment friendly alternative to synthetic chemicals for integrated pest management. Asteraceae, the largest plant family is well known for its enormously diverse characteristic content of sesquiterpene lactones. In this study the biological activity of hexane extract of Inula racemosa (Hook) was evaluated against Spodoptera litura (Fabricius). The extract exhibited larvicidal and growth inhibitory activities. A moderate antifeedant effect was recorded with maximum feeding deterrence of 24.85% at 1500 ppm of the extract. Diet supplemented with 1500–2000 ppm of the extract induced significantly higher mortality in S. litura larvae compared to control. All concentrations showed a very strong growth inhibitory effect in a dose dependent manner. The highest concentration (2500 ppm) extended the development of S. litura by 21.06 days relative to control. Due to toxic effects of I. racemosa, the adult emergence decreased significantly at concentrations ranging between 1500–2500 ppm. Sublethal effects of the extract were also manifested as morphological deformities in larvae and pupae of S. litura. Nutritional assay studies indicated reduction in growth and consumption rate as well as utilization of ingested and digested food when plant extract was fed to larvae, suggesting both antifeedant and toxic activities. The hexane extract of I. racemosa has significant influence on relative metabolic rate, causing higher metabolic cost to S. litura.

中文翻译：

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鸢尾（菊科）正己烷提取物对斜纹夜蛾（鳞翅目：夜蛾科）的生物功效

植物杀虫剂被认为是用于综合害虫管理的有效且环保的替代合成化学品的替代品。菊科是最大的植物科，其倍半萜内酯的特征含量千差万别。在这项研究中，评价了Inula racemosa（胡克）的己烷提取物对斜纹夜蛾（Fabodius）的生物活性。提取物表现出杀幼虫和生长抑制活性。记录到适度的拒食作用，在提取物1500 ppm时最大摄食威慑力为24.85％。补充1500-2000 ppm提取物的饮食会导致斜纹夜蛾的死亡率明显升高幼虫与对照相比。所有浓度以剂量依赖性方式显示出非常强的生长抑制作用。相对于对照，最高浓度（2500 ppm）使斜纹链球菌的发育延长了21.06天。由于沙门氏菌的毒性作用，浓度在1500-2500 ppm之间时，成虫的出现显着下降。提取物的亚致死作用还表现为斜纹夜蛾幼虫和p的形态畸变。营养分析研究表明，将植物提取物喂入幼虫后，生长和消耗速率的降低以及摄入和消化食物的利用率降低，表明其具有拒食性和毒性。总状I的己烷提取物对相对代谢率有重大影响，导致斜纹夜蛾的代谢成本更高。