Discipline: Veterinary Medicine
The control of Aedes (Stegomyia) aegypti Linnaeus, 1762 includes the use of synthetic chemical larvicides, which are associated with harmful environmental effects and insecticide resistance. Hence, this study investigated the larvicidal activity of crude extracts from dried black pepper (Piper nigrum Linnacus) whole fruits against Ae. aegypti. Different concentrations of the solid fractions called ether-insoluble and ether-soluble extracts and the liquid fractions denoted as water-soluble extract and water extract were assayed against third to fourth instar larvae to determine the concentrations, time exposure and LD capable of causing 100% mortality. The concentrations ranged from 12.5 to 2.50 ppm for the solid fractions and 1.56 to 3.12% extract for the liquid fractions. Distilled water, 1% ethanol and malathion at 356.25 ppm, served as controls. Results showed that all crude extracts caused 100% mortality at concentrations of 150 to 250 ppm, after 23 to 24 h of exposure to the solid extracts and 3.12% ppm after 18 to 19 h of exposure to the liquid extracts. The six-hour LD were 1061.94 and 1382.11 ppm, 5.98 and 3.01% extract for the ether-insoluble, ether-soluble, water-soluble and water extract, respectively. This shows that P. nigrum is a potential botanical source of insecticide against mosquito larval stages.