A comparative study on fumigant toxicity of Zataria multiflora and Satureja hortensis (Lamiaceae) to Callosobruchus maculatus (Coleoptera: Chrysomelidae)

Abstract

Satureja hortensis and Zataria multiflora (Lamiaceae) essential oils were tested on Callosobruchus maculatus (Fabricius) to evaluate their effects on oviposition deterrence, egg hatching and mortality of adults. To obtain essential oils, dry leaves were subjected to hydrodistillation using a modified Clevenger-type apparatus. The experiments were conducted at 25 ± 1°C and 65 ± 5% relative humidity in dark conditions with five replications for each essential oil. When concentrations of both essential oils were higher, the insecticidal effect on eggs and adults increased and oviposition was more deterred. At the highest concentration (60 μl/l air) of S. hortensis and Z. multiflora essential oils, 91.2 and 85.4% of adults were killed, respectively. There were no significant differences in oviposition deterrence between the two essential oils. At the highest concentration (4.3 μl/l air) of S. hortensis and Z. multiflora essential oils, egg mortality was 94.5 and 77.3%, respectively. Probit analysis revealed LC50 for adults and eggs of C. maculatus of 1.50 and 1.13 μl/l air, respectively, for the S. hortensis essential oil and 1.76 and 2.23 μl/l air, respectively, for the Z. multiflora essential oil. The results suggest that the essential oils of these aromatic plants can be used as botanical fumigants to protect grains against C. maculatus.