Protecting stored maize grain against the Sitophilus zeamais with rice husk ash

Maize weevil (Sitophilus zeamais) is an important insect that affect the maize grain on the field and in storage. There are several ways of controlling this insect but the most commonly used is the use of chemicals. Although these chemicals are very effective, they are often expensive and not available to poor rural farmers resulting in high post-harvest losses of their harvested grains. In this study, the potential of using rice husk ash (RHA) as a protectant against maize weevil during storage was investigated. Cultured maize weevils were introduced into 400g of maize admixed with RHA at concentrations of 5g, 10g and 20g. A control set-up of both Actellic 50EC and no RHA was set-up to compare the effect of the ash treatments on weevil mortality, re-emergence and grain damage. The treatments were replicated and set-up in the lab at room temperature condition. Results showed that, 100% mortality was observed for the Actellic 50EC treatment 5days after application. However, there was no significant difference (p>0.01) after 60 days of storage between the 20g RHA application and the Actellic 50EC relative to weevil mortality, emergence and grain damage. With the 20g RHA admixture recording the highest mortality and suppression effect on adult weevil emergence as well as the lowest grain damage, the use of RHA can provide a significant economic advantage to farmers for storage of maize in tropical developing countries if reliable recommendations on application rate can be made for the protection of stored maize.