Effects of Malathion Dust and Mexican Tea Powder ( Chenopodium ambrosoides) Combinations on the Maize Weevil, Sitophilus zeamais Mostch (Coleoptera: Curculionidae) on maize

Abstract

The experiment was conducted in the laboratory at Bako Agricultural Research Center, from February to July 2006. Combinations of different rates of malathion and Mexican tea powder were evaluated against the maize weevil in no choice situations. The treatments were laid out in a randomized complete block design with three replications. After three months of initial infestation the duration of their effectiveness of the treatments was evaluated by re-infesting with the same number of weevils as the previous. Analysis o f variance indicated significant differences among the treatments in all of the parameters measured. The rate of mortality in all
of the treatment combinations ranged from 19-100%, while that of the untreated check ranged from 0-3% following 90 days after infestation. Similarly, the number of progeny weevils emerged, percentages of grain damaged and seed weight losses in all o f the treatment combinations were significantly lower than that of the untreated check after 90 days of infestation. In terms of adult mortality ail of the combinations were as effective as standard check following 90 days after infestation. The combination treatments showed persistent effect and gave significant control over the untreated check for up to five months. However, from economic analysis (cost of treatments) point of view the least cost was observed in treatment six (T6) and can be used as a component of maize weevil management strategy.