Abstract:
Since Sri Lanka is a developing and agriculture based country, it is crucial to minimize the post harvest losses in order to increase the national income. Post-harvest deterioration is principally caused by biological spoilage organisms including insects, fungi and small vertebrates (Golob et al., 2002). The huge post-harvest losses and quality deterioration caused by insects and pests are major problems of assuring food security in developing countries. Therefore, effective and efficient controlling methods are required to eliminate this problem. Control of these insects and pests relies heavily on the use of synthetic insecticides and fumigants. But their widespread use has led to some serious problems including development of insect strains resistant to insecticides, toxic residues, on stored grain, toxicity to consumer and increasing costs of application (Jbilou., 2006). Therefore, the development of bio insecticides has been focused along with an urgent need for safe but effective biodegradable pesticides for a low cost.
This study was undertaken to screen the contact toxicity and the fumigant toxicity of Targetes erects, Bidens sulphurea, Helianthus annuus and Tithonia diversifolia which are highly abundant and underutilized herbaceous plants in Sri Lanka against Tribolium castaneum (Herbst). This method can be used as a cost effective, environmental friendly and efficient method to develop a bio insecticide as a value added product for grain storage pests.
