Vegetable powders for the control of Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae) in stored maize grains
Vegetable powders in the control of weevils
The attack by insects is one of the main causes of losses on maize during storage. The purpose of this research was to investigate the insecticidal potential action of Urtica urens L. and Piper aduncum L. powders on the maize weevils Sitophilus zeamais (Motschulsky) on stored maize. The experiment was carried out in the laboratory, with evaluation of the dry powder of U. urens leaves and P. aduncum at 3 %, and control without powder, in 80 g of maize grains infested with 0, 8, 16 and 24 maize weevil individuals. A completely randomized design was used on a 4x3 factorial scheme with four replications. The experiment was evaluated after 50 days of storage by: reduction of grain weight, percentage of grain damaged by maize weevils, grain moisture content, number of adult emerged maize weevil and mortality of maize weevil. The application of powders of P. aduncum and U. urens reduced significantly the grain damaged by S. zeamais. P. aduncum also caused a significant reduction of grain weight loss, of the number of adult emerged maize weevil and of increased the percentage of dead maize weevil. The powder of P. aduncum showed to be promising for the control of S. zeamais in stored maize grains.