SYNERGISTIC ACTIVITY OF A MIXTURE OF PONGAMIA PINNATA (KARANJ) AND KIGELIA AFRICANA (SAUSAGE TREE) LEAF EXTRACTS AGAINST YELLOW FEVER MOSQUITO, AEDES AEGYPTI

The present study was undertaken in jaipur, rajasthan, india during the year 2012. laboratory bioassays were done to evaluate the effect of karanj (pongamia pinnata) and sausage tree (kigelia africana) for their individual and combined larvicidal activity against the larvae of yellow fever mosquito, aedes aegypti. efficacy of these plants was compared with neem (azadirachta indica) which is a prominent biopesticide. leaf extracts of both the plants were prepared by soxhlet extraction method. extracts were evaluated against 3rd and 4th instar larvae using who protocol. to observe the synergistic effect, different concentrations of the plant extracts were mixed in 1:1, 1:2 and 2:1 ratios and tested against the larvae. results showed that p. pinnata (pp) and k. africana (ka) possess high larvicidal activity ( lc_50 = 63.24 ppm and lc_90 = 112.2 ppm for both plants). the mixture of two plants in 2:1 ratio (pp 75 % : ka 25%) was found to be significantly more effective (lc_50 = 25.12 ppm and lc_90 = 57.68 ppm ) than the a. indica (ai 100%) (lc_50 58.45ppm, lc_90 82.67ppm) extract. this combination exhibited maximum synergism (synergistic factor of 12.06 for 3rd instar) and was found to be 6 to 7 times more toxic than the a. indica and is thus recommended for field trials.