REPELLENT ACTIVITY OF DEVERRA TRIRADIATA (APIACEAE) EXTRACTS AGAINST ANOPHELES SERGENTII THEOBALD, CULEX PIPIENS LISTON AND CULEX ANTENNATUS BECKER MOSQUITOES

The present study evaluated the repellent activity of hexane, chloroform, methanol and ethyl acetate extracts from Deverra triradiata aerial parts against three mosquito species (Anopheles sergentii, Culex pipiens and Culex antennatus). At 3.33, 1.67, 0.83 & 0.42 mg/cm2, all tested extracts showed a variable degree of repellency against tested mosquito species depending on solvent used in extraction. The highest repellent activity attained by hexane extract, with RD50 equal to 0.704, 1.122 & 0.92 mg/cm2 against An. sergentii, Cx. pipiens and Cx. antennatus starved females, followed by ethyl acetate (0.904, 1.323 & 0.9 mg/cm2), chloroform (1.101, 1.367 & 1.157 mg/cm2) and methanol (1.183, 1.578 & 1.323 mg/cm2) extracts. Also, RD90 of hexane, chloroform, methanol and ethyl acetate extracts recorded 2.567, 2.92, 3.067 and 2.88 mg/cm2 against An. sergentii, 3.027, 3.317, 3.593 & 3.547mg/cm2 against Cx. pipiens, 2.703, 3.09, 3.267 & 2.81mg/cm2 against Cx. antennatus starved females, respectively. In addition, complete repellency time was varied according to solvent used in extraction. D. triradiata tested extracts showed a strong biting deterrency against tested mosquito species, where the highest complete repellency time (187.7min) a achieved by methanol extract against
An. sergentii starved females at 3.33 mg/cm2 and the lowest complete repellency time (57.7min) recorded by hexane extract against Cx. pipiens bites at 0.42 mg/cm2, respectively.