Atividade do óleo essencial de Lippia sidoides (Verbenaceae) e dos monoterpenos timol e carvacrol sobre larvas e pupas de Musca domestica Linnaeus, 1758 (Diptera: Muscidae)

Abstract

This study aimed to evaluate the insecticidal activity of the essential oil of Lippia sidoides and thymol and carvacrol monoterpenes against larvae and pupae of Musca domestica by contact tests. For the evaluation of larval mortality (LM) observations were made 48 hours after treatment and follow-up of surviving larvae to the adult stage, and these indices were included in the effectiveness of larval treatment (ELT). For the effectiveness of pupal treatment (EPT) were calculated pupal mortality (PM) after six days of treatment and the percentage of bad development of adults (PBD). Eight concentrations of the essential oil and pure substances, ranging from 0.625 to 30.0 mg/ml were tested. The analysis of the constituents of the essential oil thymol showed as its major component (69.91 %). The lethal dose (LD50 and LD90) for larvae and pupae were estimated and carvacrol showed the lowest values, followed by thymol and L. sidoides oil. It was found LM 100% at concentrations of 10.0 mg/ml for carvacrol, 15.0 mg/ml for L. sidoides oil and 30.0 mg/ml to thymol. As for the ELT 100% efficacy was observed starting at a concentration of 5.0 mg/ml for carvacrol and L. sidoides and 10.0 mg/ml to thymol. With respect to PM, the essential oil of L. sidoides showed no pupicida activity. However, for concentrations of 20.0 and 30.0 mg/ml was observed PBD, which contributed to EPT of 44 and 46%, respectively. As for carvacrol the highest mortality was achieved at a concentration of 20 mg/ml (58%) and to that terpene was not PBD. To thymol observed a higher PM (74%) for the concentration of 30.0 mg/ml with the PBD 60%, which contributed to 84% of EPT. The products tested showed high potential larvicide, which make them promising for the development of formulations environmentally safe and non-toxic for the control of larvae of M. domestica and that although they were not fully effective in the control pupae, their use for this stage can be indicated in a program of Integrated Pest Management.