Mediterranean Wild Herbs As Grain Protectants

In this study we explored the pesticide properties of several essential oils (EOs) yielded from aromatic plants of the Mediterranean Basin. For this purpose, the insecticidal effect of the EOs from Citrus limon (Sapindales: Rutaceae), Juniperus phoenicea (Pinales: Cupressaceae), Laurus nobilis (Laurales: Lauraceae), Echinophora tenuifollia ssp. sibthropiana (Apiales: Apiaceae), Origanum majorana and O. vulgare ssp. hirtum (Lamiales: Lamiaceae) was evaluated in laboratory bioassays on two target insect pests, the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and the khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae). The EOs were formulated to micro emulsions, with food grade emulsifier and were applied as wheat coating. Subsequently, the treated grain was infested by larvae of T. castaneum or adults of T. granarium. Mortality data obtained from the dose-response trials were subjected to probit analysis and LD₅₀ values were estimated. The LD₅₀ values for T. castaneum larvae were 416.1, 424.1, 454.5, 490.5, 539.4 and 649.4 ppm for the C. limon, E. tenuifollia ssp. sibthropiana, O. majorana, O. vulgare ssp. hirtum, L. nobilis and J. phoenicea EOs, respectively. Regarding T. granarium adults, the LD₅₀ values were 440.6, 501.3, 506.9, 530.7, 619.1, and 745.3 ppm for the O. majorana J. phoenicea, L. nobilis, O. vulgare ssp. hirtum, E. tenuifollia ssp. sibthropiana and C. limon EOs, respectively. The generated results could be useful for the management of the target stored-product insect pests by using reduced-risk plant protection products.