Nematodes are a common soybean threat, and the search for new solutions for controlling them has been the focus of many studies worldwide. Crotalaria spp. are known sources of pyrrolizidine alkaloids with nematicidal activities. In this study, the nematicidal and nematostatic effects of C. spectabilis extracts were evaluated in vitro over two different nematode species (Heterodera glycines and Meloidogyne javanica). A full factorial experimental design was employed to understand the effects and interactions of input factors (plant organ, extraction solvent, and nematode species) on the output response (nematode mortality). Ethanolic and alkaline extracts of leaves and seeds were tested at concentrations of 5, 10 and 20 mg L^-1 in bioassays with 48 hours of incubation. The C. spectabilis seed’s alkaline extract assessed for H. glycines resulted in higher mortality rates (close to 96%) compared to the other experiments. Therefore, this combination was also evaluated in vivo in a soybean plantation, resulting in a decrease of about 90% in the nematode multiplication factor compared to the control group. Ultra-High Performance Liquid Chromatography coupled to a tandem High-Resolution Mass Spectrometer (UHPLC-HRMS/MS) analyses revealed pyrrolizidine alkaloids in the extract, such as senecionine N-oxide, besides monocrotaline and its derivatives. The results obtained in this study allow new possibilities to handle nematode infections. The direct application of C. spectabilis extracts or their isolated bioactive compounds on soil can be a promising approach.

线虫是大豆的常见威胁，寻找控制线虫的新解决方案一直是全球许多研究的焦点。猪屎豆属 是具有杀线虫活性的吡咯里西啶生物碱的已知来源。在本研究中，体外评估了C. spectabilis提取物对两种不同线虫物种（大豆异皮线虫和爪哇根结线虫）的杀线虫和抑线虫作用。采用全析因实验设计来了解输入因素（植物器官、提取溶剂和线虫种类）对输出响应（线虫死亡率）的影响和相互作用。在生物测定中对浓度为 5、10 和 20 mg L ^-1的叶子和种子的乙醇和碱性提取物进行了48 小时的孵育测试。与其他实验相比，对C. spectabilis种子的碱性提取物进行甘氨酸 H.评估导致更高的死亡率（接近 96%）。因此，还在大豆种植园中对这种组合进行了体内评估，结果与对照组相比，线虫增殖因子降低了约90%。超高效液相色谱结合串联高分辨率质谱仪 (UHPLC-HRMS/MS) 分析显示，提取物中还含有吡咯里西啶生物碱，例如野百合碱及其衍生物，例如千里光碱N-氧化物。这项研究获得的结果为处理线虫感染提供了新的可能性。将C. spectabilis提取物或其分离的生物活性化合物直接应用于土壤可能是一种有前途的方法。