ABSTRACT Bioactive compounds such as polyphenols in plants have been well studied for their potential insecticidal activities. These are considered as safe alternatives against chemical pesticides because of their lower persistence in environment, lower toxicity to humans and other organisms. However, they are present constitutively in lower amounts in plants and have to undergo complicated extraction methods – hampering their commercial exploitation in pest management. Using an inexpensive extraction method developed to recover polyphenol-rich liquid extract from purple corn pericarp, we recently documented that this extract has anti-feeding effects that cascade from larval to adult stages in a model herbivore tobacco hornworm (Manduca sexta). However, M. sexta does not feed on corn or any other major crops other than the species in the nightshade family (Solanaceae). In this study, we explored the same idea but using a generalist and common herbivore on corn, the fall armyworm (Spodoptera frugiperda). We found that purple corn pericarp extract inhibited the larval growth and development as well as negatively affected the pupal stages of S. frugiperda. However, unlike on M. sexta, time to complete larval life cycle was unaffected. Our findings confirm the toxicity of this extract on a generalist, economically important herbivore, but also suggest potential species-specific effects that should be explored further.

中文翻译：

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暴露于富含多酚的紫玉米果皮提取物会限制秋粘虫（草地夜蛾）的生长

摘要 植物中的多酚等生物活性化合物因其潜在的杀虫活性而得到了很好的研究。这些被认为是化学杀虫剂的安全替代品，因为它们在环境中的持久性较低，对人类和其他生物的毒性较低。然而，它们在植物中的组成性含量较低，并且必须采用复杂的提取方法——阻碍了它们在害虫管理中的商业开发。使用一种廉价的提取方法从紫玉米果皮中回收富含多酚的液体提取物，我们最近记录了这种提取物具有抗摄食作用，在模型草食性烟草角虫（Manduca sexta）中从幼虫到成虫阶段级联。然而，M。sexta 不以玉米或除茄科植物（茄科）以外的任何其他主要作物为食。在这项研究中，我们探索了相同的想法，但在玉米上使用了一种通才和常见的食草动物，即秋粘虫（草地夜蛾）。我们发现紫玉米果皮提取物抑制了幼虫的生长和发育，并对草地贪夜蛾的蛹期产生了负面影响。然而，与 M. sexta 不同，完成幼虫生命周期的时间不受影响。我们的研究结果证实了这种提取物对一种多面手、经济上重要的食草动物的毒性，但也表明了应进一步探索的潜在物种特异性影响。我们发现紫玉米果皮提取物抑制了幼虫的生长和发育，并对草地贪夜蛾的蛹期产生了负面影响。然而，与 M. sexta 不同，完成幼虫生命周期的时间不受影响。我们的研究结果证实了这种提取物对一种多面手、经济上重要的食草动物的毒性，但也表明了应进一步探索的潜在物种特异性影响。我们发现紫玉米果皮提取物抑制了幼虫的生长和发育，并对草地贪夜蛾的蛹期产生了负面影响。然而，与 M. sexta 不同，完成幼虫生命周期的时间不受影响。我们的研究结果证实了这种提取物对一种多面手、经济上重要的食草动物的毒性，但也表明了应进一步探索的潜在物种特异性影响。