Spatial and temporal distribution of mosquito larvicidal compounds in mangroves

ObjectiveTo identify the larvicidal activity of the mangrove plant extracts.MethodsParts (bark, root, leaf and flower) of mangrove plants, Avicennia marina (A. marina), Acanthus ilicifolius, Bruguiera cylindrica and Excoecaria agallocha (E. agallocha), were dissolved in DMSO to prepare a graded series of concentration. Batches of 25 early 4th instars larvae of Aedes aegypti (Ae. aegypti) were transferred to a 250 mL enamel bowl containing 199 mL of distilled water and 1 mL of plant extracts (0.01-0.10 mg). Each experiment was conducted with three replicates and a concurrent control group. A control group consisted of 1 mL of DMSO and 199 mL of distilled water only. After 24 h, the percentage of mortality was determined.ResultsThe bark extract of A. marina showed maximum larvicidal activity against the 4th instars larvae of Ae. aegypti, followed by the leaf extract of E. agallocha. The presence of flavonoids, terpinoids and sponins in the ethanolic extracts of A. marina might be responsible for the larvicidal activity.ConclusionsIt is concluded from the present study that the mosquitocidal toxins of A. marina might be a prospective alternative in mosquito control programme involving mangrove biopesticides.