Spodoptera frugiperda is a major pest in corn crops, causing significant productivity losses and exhibiting high resistance to synthetic insecticides. Essential oils (EOs) are natural substances known for their insecticidal activity against various agricultural pests. This study describes the chemical composition and bioactivity of Drimys brasiliensis EO against S. frugiperda larvae. The EO was extracted using the steam distillation method in a vat, and its chemical composition was determined using gas chromatography coupled with mass spectrometry (GC–MS). The insecticidal activity of this EO was assessed by the contact method to estimate the lethal concentration (LC₅₀ and LC₉₀) and to evaluate the effects on biochemical markers, including glutathione S-transferase (GST), esterase-α (EST-α), esterase-β (EST-β), superoxide dismutase (SOD), acetylcholinesterase (AChE) and lipid peroxidation (LPO), in 3rd instar larvae of S. frugiperda. Twenty-nine compounds were identified by GC–MS, accounting for 81.32% of the total chemical composition D. brasiliensis EO resulted in 100% mortality of S. frugiperda larvae at a concentration of 2.5%, with LC₅₀ and LC₉₀ values of 0.90 and 1.40%, respectively. Both lethal concentrations increased AChE and LPO activity, while only LC₉₀ affected the EST-α and EST-β enzymes. Drimys brasiliensis EO exhibits insecticidal activity against S. frugiperda with neurotoxic effects, as well as cellular damage, demonstrating its potential as a control method in managing this pest in conventional and organic production methods.

草地贪夜蛾 (Spodoptera frugiperda)是玉米作物的主要害虫，会造成严重的生产力损失，并对合成杀虫剂表现出高度抗性。精油 (EO) 是天然物质，以其对各种农业害虫的杀虫活性而闻名。本研究描述了Drimys brasiliensis EO 对草地贪夜蛾幼虫的化学成分和生物活性。在大桶中使用蒸汽蒸馏法提取EO，并使用气相色谱-质谱联用仪（GC-MS）测定其化学成分。通过接触法评估该EO的杀虫活性，估算致死浓度（LC ₅₀和LC ₉₀ ）并评估对生化标志物的影响，包括谷胱甘肽S-转移酶（GST）、酯酶-α（EST-α） 、酯酶-β (EST-β)、超氧化物歧化酶 (SOD)、乙酰胆碱酯酶 (AChE) 和脂质过氧化 (LPO)，存在于草地贪夜蛾3 龄幼虫中。 GC-MS 鉴定出 29 种化合物，占总化学成分的 81.32% 。 D. brasiliensis EO 在 2.5% 浓度下导致草地贪夜蛾幼虫死亡率 100%，LC ₅₀和 LC ₉₀值为 0.90分别为 1.40% 和 1.40%。两种致死浓度都会增加 AChE 和 LPO 活性，而只有 LC ₉₀会影响 EST-α 和 EST-β 酶。 Drimys brasilien sis EO 对草地贪夜蛾表现出杀虫活性，具有神经毒性作用以及细胞损伤，表明其作为传统和有机生产方法中管理这种害虫的控制方法的潜力。