Insecticidal activity of four medicinal plant extracts against Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)

Methanol extracts from four medicinal plants, Peganum harmala (Zygophyllaceae), Ajuga iva (Labiateae), Aristolochia baetica (Aristolochiaceae) and Raphanus raphanistrum (Brassicaceae) were studied for their insecticidal effects on the stored grain pest Tribolium castaneum (Herbst). Response varied with plant species. Larvae growth was significantly inhibited when they were fed with extracts incorporated into the diet. Good insecticidal activity against T. castaneum larvae and adults was achieved with extract of P. harmala seeds, followed by extract of A. iva, Ari. baetica and R. raphanistrum aerial parts. The extracts of the four plants disrupted the developmental cycle of the insect. Extracts of P. harmala, A. iva and Ari. baetica inhibited F1 progeny production. These naturally occurring plant extracts could be useful for managing populations of T. castaneum.