Bioefficacy of Extracts of Ocimum Gratissimum Leaves on Dry Wood Termites Cryptotermes Brevis (Isoptera: Rhinotermitidae)

Abstract

The bioefficacy of leaf powder and ethanolic extracts of Ocimum gratissimum were evaluated against the dry wood termite Cryptotermes brevis in concentrations of 20-60g (powder) and 20-60ml (extract) all in three replications. The investigation revealed that mortality of termites was directly proportional to concentration of extracts and exposure time. The leaf extract proved more potent than the powder. The leaf powder also brought about repellency of the termites as they were seen to gather away from the powder. In all, there was 100% mortality of the termites in both the powder and extract treatments though the extracts brought about optimal mortality of termites in recorded time of four hours as against the powder of six hours respectively. Phytochemical screening of O. gratissimum leaves revealed the presence of the secondary metabolites such as tannins, flavonoids, terpenoids, glycosides, phenols, alkaloid and saponins working independently or synergistically to bring about the positive control of the termites. Therefore O. gratissimum should be included in traditional pest management and control systems especially in the effective control of structural insect pests since it is locally available, affordable, not toxic and environment friendly.