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Plant-based insecticides can play an important role in integrated insect pest management (IPM), especially in protecting stored grains. The aim of this study was to evaluate the bioactivity of derivatives (powder, ethanolic extract, and essential oil (EO)) from the leaves of Pimenta pseudocaryophyllus (Myrtaceae), a Brazilian native species, against Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), the main insect pest of stored corn. The powder and essential oil prepared from leaves showed a repellent effect. Moreover, the EO exhibited promising insecticidal activity through residual contact (LC50 = 1522 mg kg(-1)) and significantly decreased the F 1 progeny and the percentage of damaged grains. However, the essential oil obtained from P. pseudocaryophyllus leaves did not result in significant mortality of S. zeamais adults after 72 h of exposure by fumigation in concentrations up to 400 μL L(-1) of air. Based on GC-MS analysis, 20 compounds were identified in the essential oil of P. pseudocaryophyllus leaves, being chavibetol (38.14%), methyl eugenol (11.35%), and terpinolene (9.17%) as the major constituents. Essential oil from P. pseudocaryophyllus leaves is an interesting source of compounds with grain-protectant properties and should be analyzed in future studies aiming to develop new bioinsecticides to use in the IPM of stored grains.

A high performance liquid chromatography (HPLC) method was developed for the simultaneous isolation, on a semi-preparative scale, of chavibetol and methyleugenol from the crude essential oil of P. pseudocaryophyllus leaves. The purity of the isolated compounds and their quantifications were developed using GC/FID. Chavibetol was isolated with high purity (98.7%) and mass recovery (94.6%). The mass recovery (86.4%) and purity (85.3%) of methyleugenol were lower than those of chavibetol. Both compounds were identified on the basis of spectral analysis. The results suggest that the method can provide chavibetol with high purity, mass recovery, and productivity from crude essential, which will be used in bioassays against stored insect pests.

RESUMO:No Brasil, a lagarta-do-cartucho Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) é uma praga importante do milho e de outras espécies cultivadas, incluindo cultivos hortícolas, soja, arroz e algodão. Inseticidas botânicos são considerados uma opção interessante para o manejo de S. frugiperda, especialmente em sistemas de produção orgânica, e derivados de Annonaceae constituem uma fonte promissora destes. Diante desse potencial, o efeito do extrato etanólico de sementes de Annona mucosa -ESAM (Annonaceae) no desenvolvimento e comportamento alimentar de S. frugiperda foi avaliado através de bioensaios de exposição em meio artificial (ingestão). ESAM reduziu a viabilidade das fases larval e pupal e o peso de pupa bem como provocou um aumento na duração da fase larval de S. frugiperda. Além disso, ESAM também causou um aumento na proporção de pupas e adultos com alterações morfológicas. Entretanto, ESAM não causou efeito deterrente de alimentação para lagartas de quarto ínstar de S. frugiperda, embora esse extrato tenha ocasionado um decréscimo significativo no consumo ao longo do tempo (toxicidade pós-ingestão).Palavras-chave: inseticidas botânicos, lagarta-do-cartucho, acetogeninas, efeitos subletais. FITOSSANIDADE -ArtigoEfeito do extrato etanólico de sementes de Annona mucosa no desenvolvimento e comportamento alimentar de Spodoptera frugiperda Effect of ethanolic extract from Annona mucosa seeds on development and feeding behavior of Spodoptera frugiperda