Insecticidal activity, toxicity and biochemical alterations of Drimys brasiliensis essential oil against Spodoptera frugiperda

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.