Toxicity of Aromatic Plants and Their Constituents Against Coleopteran Stored Products Insect Pests

Abstract

Many insecticides have been used for managing stored products insect pests, especially coleopteran insects such as beetles and weevils because most of them have cosmopolitan distribution and are destructive insects damaging various stored cereals, legumes and food stuffs. Approximately one-third of the worldwide food production has been economically affected, valued annually at more than 100 billion USD, by more than 20,000 species of field and storage insect pests, which can cause serious post-harvest losses from up to 9% in developed countries to 43% of the highest losses occur in developing African and Asian countries (Jacobson, 1982; Pimentel, 1991). Among the most serious economic insect pests of grains, internal feeders such as Rhyzopertha dominica and Sitophilus oryzae are primary insect pests (Phillips & Throne, 2010). The former lays eggs outside the kernel and hatching larvae intrude into it to complete development to the adult stage, and the latter lays eggs directly inside the kernel. The other commonly found insects in shelled kennel are Sitophilus zeamais and Sitotroga cerealella. In addition, external feeders such as Tribolium castaneum, Cryptolestes ferrugineus, and Oryzaephilus surinamensis are commonly found insect pests in wheat or maize. Especially, R. dominica, S. oryzae, and S. cerealella are major internal feeding pests of rice. Most of them belong to the order of Coleoptera.