Plutella xylostella is a destructive cabbage pest responsible for huge economic losses. Heavy and continuous application of synthetic pesticides to control this pest has resulted in numerous environmental issues. Thus, discovering alternative methods to control P. xylostella, with reduced harmful effects has become crucial. In the present study we investigated the antifeedant activities and contact toxicities of two peptaibiotics, trichocellin A-I and B-II, produced by an endophytic fungus Trichoderma reesei against P. xylostella larvae. The two compounds were isolated using bioassay guided chromatographic methods from an ethyl acetate extract of T. reesei, isolated from the sedge Cyperus iria. The chemical structures of the two compounds were elucidated using mass spectrometric and NMR data. Both trichocellins showed 100% feeding deterrence activity against P. xylostella while the DC₅₀ value for trichocellin A-I was 2.38 µg cm⁻². The amount isolated was not sufficient to determine the DC₅₀ value for trichocellin B-II. In addition, both compounds showed moderate contact toxicities against P. xylostella larvae having a mean motility around 40–50%. Trichocellin A-I and B-II, have previously been reported as having antibiotic properties. However, this is the first study to report the antifeedant and contact toxicities of trichocellin A-I and B-II against the economically important insect pest P. xylostella. The results of this study encourage further investigation of secondary metabolites of Trichoderma species for development as natural pest control agents in agriculture.

小菜蛾是一种破坏性的卷心菜害虫，造成巨大的经济损失。为控制这种害虫而大量连续使用合成杀虫剂已导致许多环境问题。因此，发现控制小菜蛾的替代方法并减少有害影响变得至关重要。在本研究中，我们研究了由内生真菌里氏木霉产生的两种肽菌素 AI 和 B-II对小菜蛾幼虫的拒食活性和接触毒性。使用生物测定引导色谱法从里氏木霉的乙酸乙酯提取物中分离这两种化合物，该提取物是从莎草莎草中分离出来的。使用质谱和核磁共振数据阐明了两种化合物的化学结构。两种单线菌素都显示出对小菜蛾的100% 摄食威慑活性，而单线菌素 AI的 DC ₅₀值为 2.38 µg cm ^-2。分离的量不足以确定滴虫纤维素 B-II的 DC ₅₀值。此外，两种化合物对小菜蛾幼虫均表现出中等接触毒性，平均运动性约为 40-50%。Trichocellin AI 和 B-II 先前已被报道为具有抗生素特性。然而，这是第一项报告了单孢菌素 AI 和 B-II 对具有重要经济意义的害虫的拒食和接触毒性的研究。小菜蛾。这项研究的结果鼓励进一步研究木霉属物种的次生代谢产物，以作为农业中的天然害虫防治剂。