Browsing by Author "Ally, Hamisi"

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    Assessment of larvicidal activity of sisal leaves decortication juice against mosquito larvae
    (University of Dar es Salaam, 2011) Ally, Hamisi
    Aqueous extracts of two sisal species (Agave sisalana and Agave hybrid 11648) were tested in a laboratory for larvicidal properties against mosquito larvae. Culex quinquefasciatus mosquito larvae were used as a representative for other species of mosquitoes. The endeavour is to further explore the use of natural insecticides in integrated vector management programmes to control mosquito and solve the environmental problems caused by synthetic insecticides and sisal industry. Laboratory reared larvae were exposed to 0.125% to 1.5% v/v concentrations of the extracts of Agave sisalana and Agave hybrid 11648. Larvicidal assays were conducted according to standard WHO procedure 2005 with some modifications. Results showed that, extracts from both tested sisal species were effective against Larvae of Cx. quinquefasciatus. The LC50 of the hybrid 11648 for experiments conducted without heating and freezing after 24 and 48 hours of exposure was 0.20% and 0.18% respectively, while the LC90 were 0.25% and 0.23%, respectively. For A. sisalana, the LC50 were 0.65% and 0.25% while the LC90 were 1.16% and 0.56%. respectively. These results indicate that the sisal decortication juice currently an abundant waste causing significant pollution of rivers, could be used as a mosquito larvicide in the practical control of mosquito in small volume aquatic habitats or breeding sites around human dwellings. Further research regarding the active substances in the two Agave plants is needed to understand the mechanism of action of active substances on mosquito larvae. Also vectors of various tropical diseases Can be subjected to this kind of study. These researches undoubtedly will lead the improved formulations with enhanced activity.