PROSPECTING AND TOXICITY OF ESSENTIAL OILS FROM PIPERACEAE ON Spodoptera frugiperda (LEPIDOPTERA: NOCTUIDAE) UNDER LABORATORY CONDITIONS
Piperaceae; Essential oil; Ovicidal activity; Larval toxicity; Pest management.
Spodoptera frugiperda, the fall armyworm, causes significant damage to maize crops, with yield losses that can exceed 50% of production, in addition to attacking over 350 plant species. Therefore, products with lower environmental impact became necessary. Previous research on the genus Piper has already demonstrated its insecticidal potential, linked to bioactive compounds present in these plants. Thus, the bioactivity of essential oils (EOs) from the genus Piper against S. frugiperda was tested under laboratory conditions as a more sustainable alternative to mineral chemical pesticides. Ovicidal and larvicidal activities were evaluated against eggs (0 -24 hours old) and second-instar larvae, in a completely randomized design with ten replications. Six concentrations (0.25; 0.5; 1; 2; 4 and 8%) and two controls (distilled water and analytical-grade acetone) were tested, totaling eight treatments per species. The chemical composition of the EOs was determined by gas chromatography coupled with mass spectrometry (GC-MS). Data were analyzed by ANOVA with Bonferroni test (α = 0.05) and lethal concentrations estimated by the Probit method. A dose-dependent effect was observed in both activities. In the ovicidal bioassay, P. marginatum and P. fuligineum rendered eggs unviable at concentrations ranging from 1% to 8%, while P. hispidum showed activity only at 4% and 8%. The chemical composition of P. marginatum and P. divaricatum is rich in sesquiterpenes, mainly Germacrene B and D, whereas P. aduncum and P. hispidum show a predominance of volatile monoterpenes, such as α-pinene. P. marginatum and P. fuligineum, from 1% onwards, caused 50% mortality in larvae. The sesquiterpene-rich essential oils of P. marginatum and P. fuligineum show promise for pest control.