Inhibición de Desarrollo de Larvas Culex quinquefasciatus¹ Say con Extractos de Semilla y de Hoja de Ricinus communis²

The toxic effect of methanolic, hexane, and ethyl acetate extracts of seed and leaf of Ricinus communis on the inhibition of growth and development of Culex quinquefasciatus (Say) mosquitoes was determined. The hexane leaf extract affected the development of larvae with a mean effective concentration (EC) EC50 = 176.1 ppm, and leaf ethyl acetate eliminated 100% of the larvae at 1.7 days. Treatments with lower development inhibition index (DII) were three of leaf: Ethyl acetate with 1, 250, and 625 ppm with formation of 0.0 and 1.3 of pupae and without adults and 625 ppm shortened the larval duration in 2.3 days, followed by hexane with 625 ppm with formation of 12.5 of pupae and 0 adults decreased the larval period in 2.8 days, with DII of 0.000, 0.013, and 0.063, and three of seed: At 1, 250, 625, and 312.5 ppm of ethyl acetate, hexane, and methanol that affected the viabilities and the hexanic at 1, 250, y 312.5 ppm increased the pupal period in 1.5 and 1.6 days, the first concentration of the three solvents with DII values of 0.250, 0.331, and 0.338. The leaf hexanic at 1, 250, and 312.5 ppm and methanol at 1, 250 ppm affected the viability, resulting in subsequent DII's of 0.081 and 0.169, and 0.113, with 0, 5, and 10 adults formed and with methanolic at 1, 250 ppm with the minimum number of adults. The study showed that the extracts ethyl acetate, hexane, and methanol of leaf of R. communis inhibited 50% the development of the population of larvae of IV instar early of Cx. quinquefasciatus with 272.82, 176.06, and 924.58 ppm and those of seed with 677.37, 652.33, and 705.53 ppm, which affected larval and pupal duration and viability to the extent of avoiding the formation of pupae and adult emergency. These results demonstrate the potential of leaf and seed extracts of this plant species to be included as an alternative to the control of Cx. quinquefasciatus.