Effect of Rice Husk and Melon Shell Wastes as Possible Grain Protectants in Cowpea Storage

Aims: This study sought to determine the effect of rice husk and melon shell powders and ashes in the control of Callosobruchus maculatus- a storage pest of cowpea.

Study Design: Completely Randomized Design (CRD).

Place and Duration of Study: Entomology Section, Cocoa Research Institute of Nigeria; year 2015.

Methodology: Clean cowpea samples were inoculated with five pairs (male and female) of newly emerged Callosobruchus maculatus (a major constraint in the storage of cowpea in the tropics) and treated with powders and ashes of rice husk and melon shell at different levels. Data obtained were subjected to statistical analysis.

Results: Samples treated with rice husk ash (RHA) recorded 100% pest mortality at 1.0-2.0 g/20 g cowpea just like the standard, and followed by melon shell ash (MSA) and rice husk powder (RHP) which gave 93.33 and 70% mortality respectively at 2.0 g/20 g. RHA showed significantly highest percentage oviposition inhibition (P ≤ .05), followed by MSA and RHP.

Conclusion: While the viability of the cowpea seeds was preserved by powders and ashes of melon shell and rice husk used, RHA showed a distinctive protection against C. maculatus. Ashes and powders of agricultural wastes like rice husk and melon shell can therefore be employed as safer alternatives to synthetic insecticides in the control of C. maculatus in cowpea storage.