The Use of the Different Rates of Clove Powder to Protect Processed Meals Against the Red Rust Flour Beetle

ABSTRACT

The effect of different rate of clove powder was studied to protect seven different staple meals (Semovita® grits, millet, wheat, cassava, maize, yam and cowpea flours against infestation by the rust red flour beetle, Tribolum castaneum (Herbst.). The clove powder was evaluated at the dosage rates of 0.25, 0.5, 0.75 and 1.0 g/20 g of the different staple meals in a 50 ml transparent plastic vial and a control treatment set along without the addition of the clove powder. The experiment was carried out as treatment before infestation (TBI) with each treatment replicated three times and laid down in a complete randomized design. The staples meals were pulverized and each 20 ml was inoculated with four pairs of adult unsexed T. castaneum. Test insects were allowed to oviposit for twenty days on an already treated staple meal with the clove powder. After twenty days, all adults (both live and dead) were removed and recorded. Thereafter, adult emergence were taken daily for twenty eight days after infestation all adult beetle that emerged were removed, counted and recorded on a daily basis for a period of thirty days covering the first generation of beetles. The results of the mortality rate showed differential responses on the treated staple meals with clove powder. Significantly (p≤0.05) more T. castaneum adult emerged in wheat, millet flours and Semovita® grits while fewer adults emerged in yam, cassava, maize and cowpea. The results also indicated that the clove powder contains anti-nutrients such as alkaloid, flavonoids, saponins and tanins that can affect the emergence or infestation of insects regardless of dosage and as such, was found to be more potent in suppressing the emergence of T. castaneum in the meals.