Stored Grains Protection Activity of Ocimum Suave Extracts and Compounds on Larger Grain Borer

Abstract

Post-harvest pests cause serious losses to agricultural products in Africa. The pests consist mostly of beetles or moths and infest the grains at the crop stage or during the storage. Larger grain borer, Prostephanus truncatus (Horn), causes maize-grain losses during storage ranging from 30% to greater 40% of total production in 6 months. It reduces germination potential of maize grain and increases the grain’s moisture content thus accelerating contamination by fungi and bacteria. The aim of this study was to determine the insecticidal extracts and compounds from Ocimum suave. Percentage mortality of the insects were recorded 1, 2, 14 and 21 days after treatment while adult emergence inhibition and weight loss prevention activities were recorded 42 days after treatment. The essential oil of the plant gave 75.4, 77.1 and 78.5% mortality after 7, 14 and 21 days respectively, while leaf powder gave 50.3, 63.7 and 66.6% mortality after 7, 14 and 21 days respectively. Betulinic acid gave 56.9 and 58.1% mortality 14 and 21 days after treatment respectively. The essential oil completely prevented the emergence of the insects and also completely prevented weight loss of maize grains. The findings from this study have provided scientific data to support the use of Ocimum suave to control insect pests. Further studies aimed at identification on plant materials which can be used in pest management are highly recommende