Bio-Efficacy Of Some Indigenous Ghanaian Botanical Against The Almond Meal Moth: Ephestia Cautella (Walker)

ABSTRACT Ephestia cautella is one of the most important stored product insect pests found in granaries. Its activities tend to reduce germination and nutritive capacity of the infested seed and grains. The increasing rate of pest resistance, high cost and health risk in the use of insecticides to control insect pest have become issue of public concern. Therefore the use of botanical has been found to be very effective against stored product insect pests. Several plant products (leaves, oil, ash, seed extracts, and roots) are processed and mixed with stored products or applied as insecticides to control these pests. These are considered to be cheap, easily biodegradable and readily available for stored product protection. In this research, the bioefficacies of Moringa oleifera, Ocimum canum, Securidaca longepedunculata and Zanthoxylum xanthoxyloides as bio-insecticidal agents against E. cautella were investigated. The powders of M. oleifera, O.canum, S. longepedunculata and Z. xanthoxyloides leaves were screened in the laboratory against the adults E. Cautella in the proportion of 50% and 100% wt/wt for all the botanicals. These showed the various bioactivities against the insects with 100% wt/wt treatments of Zanthoxlum xanthoxyloides proving to be most effective, as it significantly reduced the survival (90%) of the insects. The effect of petroleum ether extracts of the botanicals at different concentration (0.1g/mL, 0.3g/mL and 0.5g/mL) on the adult insect by grain treatment, effects on immature stages, effects on adult emergence in treated grains repellency, damage to the grains and germination tests were determined in the laboratory. The study showed that, the ability of the petroleum ether extracts to cause mortality was dosage dependent since mortality increased with higher concentration of the extracts. Significantly (p=0.005) lower number of eggs were laid on the treated grains compared with the untreated control. The botanicals had a tremendous effect on the adult emergence of E. cautella. There was no adult emergency at the highest concentration (0.5g/ml) for Moringa oleifera. There were significant differences in the number of adults  emergence between the various treatments and the control. Overall percentage weight loss was lower (0.0-6.80%) in the botanical treatments than that of the untreated control (9.4-31.51%). Grains treated with botanicals gave an appreciable reduction in weight loss as compared with the control. Studies on the effects of the botanical on seed viability revealed that the botanicals did not hamper seed viability after 60 days storage period. The untreated control had the least percentage germination (25.0-25.3%). There was significant repellence of the insect by the different concentrations of the plant extracts. These results indicate that good protection of maize seed can be offered by indigenous Ghanaians botanicals acting as both repellents and anifeedants against Ephestia Cautella.