Insecticidal activity of Vanillosmopsis arborea essential oil and of its major constituent α-bisabolol against Callosobruchus maculatus (Coleoptera: Chrysomelidae)

Vigna unguiculata , one of the most important legumes, mainly in underdeveloped countries, is susceptible to post-harvest losses in storage by Callosobruchus maculatus (Fabricius, 1775) (Coleoptera: Chrysomelidae). The work evaluated the toxicity, inhibition of oviposition, instantaneous rate of population growth (r i ) and the development of fumigated C. maculatus with the essential oil of Vanillosmopsis arborea and its major constituent, α -bisabolol. The experimental units consisted of 0.8 L flasks treated with concentrations of 1.2–11.2 μL L −1 of air of the essential oil of V. arborea or its major constituent applied to disks of filter paper. α -Bisabolol was quantified as 409.33 mL L −1 of the essential oil. The development rate of C. maculatus was evaluated by daily adult counts. Oviposition was evaluated at lethal concentrations (LC 50 , LC 25 , LC 10 and LC 1 ). The LC 50 and LC 95 of the essential oil of V. arborea and α -bisabolol were 5.23 and 12.97 μL L −1 of air and 2.47 and 8.82 μL L −1 of air, respectively. At some concentrations, the α -bisabolol was more toxic to males than to females of the insect. Increased concentrations of the essential oil reduced the r i , rate of development, oviposition, and number of eggs of C. maculatus and therefore have potential for pest control.