Efeitos de óleo essencial e compostos isolados sobre parâmetros histofisiológicos, histoquímicos, imunohistoquímico, nutricionais e embriológicos de Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

Abstract

The present research had the following objectives: (i) to analyze the effects of limonene and trans-anethole compounds, isolated or associated, by different routes of application, in order to verify histological, histochemical and apoptosis effects on the midgut of Spodotera frugiperda; (ii) to investigate the sublethal and lethal effects of the isolated, geraniol and citronellal compounds on biochemical and reproductive parameters of S. frugiperda; (iii) to evaluate the chemical composition of Piper marginatum oil; establish LCs 30 and 50 of this oil and the geraniol compound, as well as histologically examine the embryonic development of S. frugiperda through light microscopy and scanning electron. The results demonstrated that limonene and trans-anethole interfered in the histology of epithelial tissue, the levels of neutral polysaccharides and proteins in 48 e 96 h, and different modes of application. However, they did not promote apoptosis. Trans-anethole presented greater isolated or associated efficiency when applied by ingestion. Geraniol and citronellal caused a reduction in the concentration of proteins and sugars in both concentrations. There was no change in lipid concentration. However, citronellal increased the glycogen for LDs 30 and 50. The oviposition period and the number of eggs were reduced. The chemical composition of P. marginatum oil identified 44 compounds. LCs 30 and 50 were estimated at 32.32 and 152.95 ppm, for oil and geraniol, 0.98 and 3.58 ppm, respectively. Light and scanning electron microscopy showed that oil, geraniol, azadirachtin and deltamethrin affected the embryonic development and egg morphology at both concentrations, however, the oil and compound were more efficient because of damage more expressive even at the lowest concentrations. It is inferred, therefore, that the compounds and oil used are efficient for the control of S. frugiperda.