Ageratum conyzoides, Chromolaena odorata, and Lantana camara, are common weed species in Cameroon. Essential oil extracts from their leaves were tested for efficacy on the morality of the maize grain weevil, Sitophilus zeamais (Coleoptera, Curculionidae). Concentrations of the essential oils relative to the maize grains of 0.013, 0.025, 0.05 and 0.1% (v/w) were used for A. conyzoides and 0.063,...