Repellent action of Cashew (Anacardium occidentale L.)Nut Shell Liquid
Repellent action of Cashew (Anacardium occidentale L.)Nut Shell Liquid
Cashew Nut Shell Liquid (CNSL) was extracted from Soxhlet using two different solvents hexane and dichloromethane. The CNSL extract was concentrated using a Rota vapor set at 100 rpm to remove the excess solvent. The CNSL extract, dark brown in colour was allowed to run in the Rota vapor for 1h before being placed in an Eco cell oven set at 40°C and dried to constant weight. The extract was then transferred into a vile and used as a stock solution from which different concentrations were prepared. Solutions were prepared by dissolving 2, 4, 6, 8 or 10 µL of each CNSL extract in 1mL acetone to produce concentrations of 0.07, 0.14, 0.21, 0.28, and 0.35 µL/cm2 of extract. The hexane extract at a concentration of 0.35 µL/cm2 gave a higher repellency of 76% as compared to other concentrations tested while the dichloromethane extract recorded 48% repellency at the same concentration after 24 hours. This study potentially demonstrates the use of CNSL extract as a repellent against Bactrocera dorsalis. This study focused on reduce the risk of pesticide poisoning among papaya consumers by the direct application of synthetic insecticides. The repellent action of the CNSL extract also prevent the insects from laying their eggs inside fruits if applied timely intervention and minimize the environmental and other health hazards. Pest control using the botanicals extracts that influence the behavior of the pest by repellence can be complementary to insecticide use because the extracts would not interfere with the insecticide mode of action. Furthermore, the botanical extracts can disrupt host insect interactions by repelling insects from a host, deterring feeding or egg-laying.
Reference:
Keita, S. and Zuharah, W.F., Repellent action of Cashew (Anacardium occidentale L.) Nut Shell Liquid (CNSL) on adult papaya fruit fly Bactrocera dorsalis (Hendel)(Diptera: Tephritidae).
