Effects of Moringa oleifera root and leaf powder on reproductive capacity and damage caused on stored cowpea seed by Callosobruchus maculatus (F).

Abstract

A laboratory study was conducted to investigate the effect of Moringa (Moringa oleifera) root and leaf powder on reproduction and damage to cowpea seed by Callosobruchus maculatus F at Botswana College of Agriculture in Gaborone, Botswana, in March 2012. Two experiments were conducted to test the effects of moringa leaf and root powder on C. maculatus using susceptible cowpea variety blackeye. The root powder was applied at dosages of 10%, 15%, 20%, 25%, and 30% of 8.00g seed while leaf powder was applied at 10%, 15%, 20%, 25%, 30%, 35% and 40% of 8.00g of seed. Malathion was included in both experiments as a check, applied at dosage of 0.01g per kg of seed. The results showed that moringa root powder significantly protected cowpea seed against damage by C. maculatus. We observed significant reduction in number of eggs laid, percentage of eggs hatched percentage of adult emerged, number of exit holes and seed weight loss when seeds were protected by moringa root powder. Mixing seeds with leaf powder did not significantly affect the number of eggs laid, the number of hatched eggs, the number of adults emerged, the number of exit holes and percentage seed weight loss. It is therefore considered that based on the dosages used in this experiment, moringa leaf powder may not be effective in reducing seed damage by C. maculatus. In contrast, moringa root powder has potential to reduce damage by C. maculatus on stored cowpea seed.