Contact toxicity of Lavandula angustifolia Mill and Zataria multiflora Boiss essential oils against the adults of Callosobruchus maculates (F.) (Col., Bruchidae) and identification of their chemical compositions

In last decades, many researches have been done on use of botanical compound especially essential oils as insecticides. In the present study, the contact toxicity of Lavandula angustifolia and Zataria multiflora essential oils was evaluated on both sexes of C. maculatus adults at 29± ºC, 60±5% RH in dark condition. Essential oils were obtained by hydro distillation. The toxicity of both oils against males and females was positively and significantly associated with concentration. On the basis of LC50 ratios and their 95% confidence limits, there was no significant difference between sensitivity of males and females. The LC50 values for males were 719 and 598 l.m-2 and for females were 787 and 738 l.m-2 for L. angustifolia and Z. multiflora, respectively. Both essential oils had no negative effect on seed germination of the cowpea. The essential oils analysis by GC-MS showed that the main compounds of L. angustifolia oil were linalool (42.8%), 1,8- cineol (23.4%), rosefuran epoxide (14%), menthone (6.8%), isomenthol (5.2%) and dihydro carvone (trans) (4.3%) and those of Z. multiflora oil were thymol (55%), linalool (37.8%) and pcymene (7.2%). The results suggested that L. angustifolia and Z. multiflora essential oils might be suitable alternatives to conventional pesticides for protecting pulses against C. maculatus adult.