Browsing by Author "Mdoe, France Peter"

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    Larvicidal efficacy of the leaf essential oils from selected plant species against anopheles gambiae sensu stricto (diptera: culicidae)
    (University of Dar es salaam, 2015) Mdoe, France Peter
    In combating mosquito insecticide resistance in sub-Saharan Africa, attention has now focused on larval control using plant-derived insecticides. In the present study, larvicidal efficacy of the leaf essential oils from five selected plant species, namely; Tagetes patula L (Asteraceae), Clausena anisata Willd (Rutaceae), Cinnamomum osmophloeum Kaneh (Lauraceae), Cryptomeria japonica D. Don (Cupressaceae) and Feronia limonia L (Rutaceae) were investigated against third instar larvae of An. gambiae s.s. The bioassays i.e; 200, 100, 50, 25 and 12.5µg/ml, in six replicates and two controls were prepared. 20 third instar larvae were used and mortality was monitored at 12, 24, 48 and 72 h. The WHO test procedures for monitoring larvicidal efficacy in malaria vectors were used. Results showed significant differences (P< 0.05) in larvicidal efficacy among the five plant leaf essential oils tested under both laboratory and semi field conditions (one way ANOVA, Tukey test). Larvicidal efficacy varied with species of plants, treatment dosages and exposure time. The leaf essential oils from C. osmophloeum and C. japonica revealed best larvicidal efficacy under both laboratory and semi field conditions, whereas, T. patula and C. anisata were the weakest larvicides under laboratory and semi field trials, respectively. The differences were attributed to variation in chemical constituents of the essential oils, their mode of action and environmental factors. Therefore, the larvicidal efficacy shown by the essential oils in the present study is a promising alternative to existing larvicides for the control of An. gambiae s.s.