摘要
Objective:To evaluate the insecticidal potential of Alstonia boonei(A.boonei)oils and derivatives against different life stages of a malaria vector,Anopheles gambiae.Methods:The leaf,stem bark and root bark of A.boonei were collected from an open field and air dried before being blended to fine powder.Oils from this plant were extracted by cold extraction and were prepared at different concentrations.Contact toxicity of A.boonei was tested against the larvae and pupae of the insect while smoke toxicity of the plant materials in form of mosquito coil was tested against the adult insect.Results:Alstodine recorded the highest insect mortality rate and the order of susceptibility of the life stages of the insect to the plant was pupae<adult<larvae.Alstodine recorded the highest repellant activity(100%)after 4-5 h of application.However,all the treatments achieved high repellency(above 70%)after 6-7 h of application compared with the control.The formulated mosquito coil(smoke)of A.boonei oil extracts and derivatives showed high rate of protectability as they achieved above 55%protection.Moreover,alstodine(83.22%)showed the greatest smoke toxicity effect on the insect as it recorded almost the same percentage protection as the positive control(Raid synthetic insecticide)which recorded 83.56%protection.Conclusions:This present study has proven A.boonei oil extracts and derivatives as a potential botanical insecticide which could serve as a new thoroughfare of mosquito control.Moreover,the order of effectiveness of the plant can be arranged thus:alstodine>alstonine>stem bark extract>leaf extract>root bark extract.
