The action of clove (Syzygium aromaticum) and thyme (Thymus vulgaris) essential oils in the control of Acanthhoscelides obtectus (Coleoptera: Chrysomelidae) in laboratory

Abstract

The objective of this study was to assess the efficiency of essential oils of cloves (Syzygium aromaticum) and thyme (Thymus vulgaris) on the control of Acanthoscelides obtectus in laboratory conditions. The extraction of the oils was executed by the hydro-distillation method in a Clevenger device, for 4 hours and the design used was completely randomized, with five replications, in a 10x8 factorial arrangement (dozes and exposition time) with ten concentrations (20; 10; 5; 2.5; 1.75; 0.75; 0.5; 0.25 and 0.0% and Tween® 5.0%). Each replication was comprised by 10 unsexed insects of A. obtectus. The variables evaluated are as follows: control efficiency and CL50 through the Proc Probit analysis. The evaluations were carried out in 1, 2, 3, 12, 24, 48, 72, and 96 hours after the treatment. The results demonstrate that the essential oils of cloves and thyme caused 100% of mortality after 48 and 72 hours, respectively, in the 20% concentration. The Cl50 was estimated at 30.46 µL mL-1 for the oil of cloves and 24.93 µL mL-1 for the oil of thyme. The use of essential oils of cloves and thyme represent a viable alternative for use in storehouses for the integrated management of A. obtectus.