Toxcicity of Temphos, Diazinon and Acacia nilotica Extracts to Larvae of Culex quinquefasciatus , Kartoum State.

Abstract

Background:Mosquito control is becoming increasingly difficult because of the development ofvector resistance to conventional insecticides. Many efforts were made to search for insecticides of natural origin as safe alternative to synthetic insecticides. Pesticides derived from plants have the potential to play a major role in pest management and control of larvae of different species of mosquito. They are renewable, non- persistent in the environment and relatively safe to natural enemies. The lack of adequate drainage in many areas even the provision of drainageandwater stagnation is promoting the breeding of Culex quinquefasciatus. The study aimed to compare the susceptibility of larval stages of Culex quinquefasciatusto temphos,diazinon and Acacia nilotica fruits water extract. Methods:Susceptibility of Culex quinquefasciatuslarvae totemphos (Abate), diazinon and Acacia nilotica fruits water extracts, was carried out, following WHO standard susceptibility tests. The larvae of the 3rd and 4th stage of Culex quinquefasciatus mosquito were collected from the breeding sites of polluted water with organic matter.e.g sewage water and rainy season swamps in JebalAwalia Locality. Larvae were exposed to a series of temphos, diazinon and Acacia nilotica fruits water extract concentrations. Data was subjected to probit analysis and values of LC50 and LC98 of experimental larvae were calculated. Results:The average percentage death for Culex quinquefasciatuslarvae in the four experiments in temphos ranged Please purchase PDFcamp Printer on http://www.verypdf.com/ to remove this watermark. IV between 16% and 96%. The LC50 and LC98for temphos were 0.087 ppb and 53.1 ppb, respectively. The average percentage death for Culex quinquefasciatuslarvae in the four experiments in diazinon ranged between 11%and 100%. The LC50 and LC98for diazinon were 0.22 ppb and10.8 ppb, respectively. The average percentage death for Culex quinquefasciatuslarvae in the four experiments in Acacia nilotica fruits water extract ranged between12% and 85%. The LC50 and LC98for Acacia nilotica fruits water extract 8 ppband 3851.7 ppb, respectively. The study revealed low susceptibility ofCulex quinquefasciatuslarvae toAcacia nilotica fruits water extract, high susceptibility to diazinon and higher susceptibility to temphos. Conclusion:The current results of Acacia nilotica fruits water extract were considered promising to proceed in studying thebioactive plants which represent an environmentally safe alternative to thesynthetic larvicides. Temphos was more toxic than diazinon on Culex quinquefasciatus larvae under laboratory condition.Finally the following recommendations were made: The extraction procedures of Acacia nilotica fruits need to be improved to separate active ingredients foremore deep testing. Monitoring susceptibility of mosquitoes to insecticides must be repeated more thanonce per year.