Insecticidal Activity on Callosobruchus Maculatus of Essential Oils Extracted from Naturally Grown and Cultivated Rosemary

The biological activity of the essential oils extracted from the leaves of Rosemary, Rosmarinus officinalis L. growing naturally (Honaine region, Algeria), and cultivated Rosmarinus tournefortii de Noé (Tlemcen region, Algeria) was tested under laboratory conditions against the chickpea bruchid Callosobruchus maculatus (F.) which causes losses in the field and during storage. The essential oils were tested at three different doses 1, 3, and 5 µL/30 g of seeds, on different biological parameters: adult mortality, female fecundity, and fertility of laid eggs. Results indicated that these essential oils exert varying toxicity levels on the adults of C. maculatus, with a decrease or even inhibition of the fecundity of the females and the fertility of the laid eggs at high doses. However, the essential oils of R. officinalis were more effective than that of R. tournefortii with LD50 of 2.97 and 4.74 µL/30 g of seeds and LT50 of 2.10 and 3.14 days, respectively. Thus, the chemical composition of the major toxic components in the two essential oils, like α-pinene, camphor, β-pinene, cineole, and borneol, extracted from the two national regions is essential to make use of these products as botanical insecticides.