摘要
Crude leaf extracts of Eucalyptus camaldulensis and Tylophora indica were evaluated for their antifeedancy against Helicoverpa armigera larvae in no-choice bioassays. Cabbage leaf-disc dipped in different concentrations of leaf extracts was used for feeding fifth instars of H. armigera for 24 hours. Ethanol extracts from both the plant species exhibited significant feeding inhibition, activity. The effective concentrations of ethanol extracts that caused 50% reduction in larval feeding （EI50） were 6.9% for E. camaldulensis and 2.8% for T. indica, while these values of hexane extracts were 9.3% and 5.2%, respectively. Compared to the crude leaf extracts, crude alkaloids from T. indica and crude tannins from E. camaldulensis were more potent in reducing larval feedings.
桉树类 camaldulensis 和 Tylophora indica 的粗略的叶摘录与 Helicoverpa 有佩带徽章权利的人为他们的 antifeedancy 被作比较在没有选择生物鉴定的一个幼虫。在叶摘录的不同集中蘸的 Cabbageleaf 圆盘被用于喂第五中间形态 ofH。有佩带徽章权利的人一因为 24 个小时。植物种类展出了重要的喂的从两个的乙醇摘录抑制活动。在幼虫的喂引起了 50%reduction 的乙醇摘录(EI_(50 )) 的有效集中为 E 是 6.9% 。camaldulensis 并且 2.8% 为 T。indica 当己摘录的这些价值分别地是 9.3% 和 5.2% 时。比作粗略的叶摘录，从 T 的粗略的碱。从 E 的 indica 和粗略的丹宁。camaldulensis 是在减少的更多的有势力幼虫的费用钟声。
