Larvicidal activity of indigenous plant extracts on the rural malarial vector, Anopheles culicifacies Giles. (Diptera: Culicidae)

Vector control is one of the most important components in combating vector-borne diseases throughout the world. Application of insecticides is a widely known and popular vector control strategy. The objective of the present study was to evaluate the larvicidal activity of the hexane, diethyl ether, ethyl acetate and acetone extracts of Abutilon indicum, Hyptis suaveolens and Leucas aspera against third-stage larvae of Anopheles culicifiacies. The results clearly suggest that all three selected plant extracts exhibited moderate larvicidal activity after 24, 48 and 72 h at 250, 500, 750 and 1000 ppm; the lethal concentrations (LC) at 50% and 90% of A. indicum, H. suaveolens against third instar larvae at 24, 48 and 72 h (hexane, diethyl ether, ethyl acetate and acetone) were as follows: A. indicum, LC₅₀=1031.65, 949.18, 833.58 and 673.68 ppm; LC₉₀=2215.87, 2234.39, 2152.97 and 2455.10 ppm; H. suaveolens, LC₅₀=423.00, 347.50, 236.58 and 217.24 ppm; LC₉₀=1431.91, 1292.15, 1138.49 and 1049.27 ppm and L. aspera, LC₅₀=559.77, 401.56, 299.71 and 263.01 ppm; LC₉₀=1400.80, 1549.31, 1157.96 and 1108.72 ppm at 24 h, respectively. Overall, the highest larvicidal activity was observed with H. suaveolens extract followed by L. aspera and A. indicum at various concentrations at 48 and 72 h, respectively. The objective of this investigation was an attempt to search for a user- and eco-friendly vector control agent. The study proved that the selected plant leaf extracts could serve as potent larvicidal agents against A. culicifacies in vector control programs.