Influence of the cowpea weevil, callosobruchus maculatus f., and the saw - toothed grin beetls, oryzaephilus surinamensis L. On the moisture content and mould growth in stored grains

Abstract

Presence of the cowpea weevil, Callosobruchus maculatus F., and the saw-toothed grain beetle, Orvxaephilus surinamensis L., and their propagation in cowpea and wheat, resulted in raising the moisture content of infested grains. The increase in moisture content of infested grain was greater at higher relative humidity (60 %) than at lower one (40 %). The 80 % relative humidity was unfavourable to both tested insects. The moisture content of the noninfested grains remained in equilibrium with atmospheric moisture. Fungi grew and developed more readily and in greater numbers in infested grain than in non infested one. The storage fungi continued growing in infested grains even after the death of all insects. The majority of storage fungi isolated from the tested grains belong to the genera Aspergillus, Penicillium, Alternaria, and Fusarium. A. glaucus, A. fumigatus, and Penicillium rubrum dominated the isolated mould counts.