Research Article of American Journal of Chemical Research
Bioactivity of four plant materials against the maize weevil, Sitophilus zeamais Motschulsky
Olanike T. Alade and Olalekan J. Soyelu*
Department of Crop Production and Protection, Obafemi Awolowo University, Ile-Ife 220005, Osun State, Nigeria
Fine powders of orange peel (Citrus sinensis), scent leaf (Ocimum gratissimum), morinda leaf (Morinda lucida) and lemongrass (Cymbopogon citratus) were applied against 2-day-old maize weevils, Sitophilus zeamais with a view to identifying non-chemical control agent(s) of the weevils. Growth rate, antioviposition effect, repelling efficacy and mortality due to each powder were determined. It took an average of 35.4 days for weevils to develop from egg to adult and none of the powders had adverse effect on growth rate. The powders repelled maize weevils significantly, being strongest in C. citratus. However, M. lucida did not achieve an effective antioviposition effect like the other three plants. Percent weevil mortality was higher in maize grains treated with C. citratus and M. lucida within the first one week of application but the effect remained stronger in the former beyond this period. The plant materials, especially C. citratus, showed potential for protecting maize grains against the storage pest.
Keywords: Antioviposition; Lemongrass; Maize weevil; Morinda; Mortality; Orange peel; Repellency; Scent leaf; Storage pest