Abstract The search for new compounds to control Plutella xylostella, the main pest of Brassica crops, has been stimulated by the environmental impact of the insecticides currently used and reports of resistant populations. This work evaluated the effects of a cladode extract from Opuntia ficus-indica (CE) on the survival and development of P. xylostella, as well as on its oviposition behavior. Additionally, the effects on the histological organization of the larval midgut, as well as digestive enzyme activities, were evaluated. CE contained flavonoids, cinnamic derivatives, terpenes, steroids, and reducing sugars. High-performance liquid chromatography analysis confirmed the presence of rutin and compounds containing aliphatic chains and aromatic rings in their structures. CE reduced the viability of eggs with an EC50 (concentration that reduces egg viability by 50%) at 5.37% (w/v) and killed larvae with an LC50 (concentration that kills 50% of larvae) at 7.75% (w/v). Histological analysis revealed several alterations in the midgut of larvae exposed to the extract, including the presence of spherites, cell nuclei expulsion, the disappearance of the peritrophic membrane, and an increase in the number of goblet cells. CE inhibited the in vitro activity of proteases from larvae midgut extracts. The extract also presented oviposition-deterrent activity. In conclusion, cladodes of O. ficus-indica are a source of compounds toxic to eggs and larvae of P. xylostella and are able to interfere with oviposition site choice. The results suggest potential of CE as a botanical insecticide, though field trials are needed to confirm activity.

中文翻译：

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Opuntia ficus-indica cladode 提取物是小菜蛾 Plutella xylostella 的胚胎毒性、杀幼虫和排卵剂

摘要 目前使用的杀虫剂对环境的影响和抗药性种群的报告刺激了对控制小菜蛾（芸苔属作物的主要害虫）的新化合物的研究。这项工作评估了仙人掌 (CE) 枝叶提取物对小菜蛾生存和发育及其产卵行为的影响。此外，还评估了对幼虫中肠组织学以及消化酶活性的影响。CE 含有类黄酮、肉桂衍生物、萜烯、类固醇和还原糖。高效液相色谱分析证实了芦丁及其结构中含有脂肪链和芳香环的化合物的存在。CE 以 5.37% (w/v) 的 EC50（使卵活力降低 50% 的浓度）降低了卵的活力，并以 7.75% (w/v) 的 LC50（杀死 50% 幼虫的浓度）杀死了幼虫. 组织学分析显示，暴露于提取物的幼虫中肠发生了一些变化，包括球粒的存在、细胞核排出、围营养膜的消失和杯状细胞数量的增加。CE 抑制来自幼虫中肠提取物的蛋白酶的体外活性。该提取物还具有排卵威慑活性。总之，O. ficus-indica 的枝条是对小菜蛾的卵和幼虫有毒的化合物的来源，并且能够干扰产卵地点的选择。结果表明 CE 作为植物杀虫剂的潜力，