Evaluation Of Ovicidal And Larvicidal Effects Of Plant Extracts From Family Anacardiaceae Against Aedes Aegypti And Aedes Albopictus (Diptera: Culicidae).
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Date
2016-07
Authors
Yousaf Ali
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Abstract
Phytochemicals are getting hype in mosquito control programs as a pertinent substitute to synthetic pesticides. The objective of this study is to explore the ovicidal and larvicidal effects of Anacardium occidentale, Gluta renghas, Mangifera indica and Melanochyla fasciculiflora from family Anacardiaceae against the dengue vectors; Aedes aegypti and Ae. albopictus and biological comparisons of their progenies. Laboratory and field strains of dengue vectors were exposed to methanolic extracts of stem and leaf parts. Gluta renghas stem displayed the lowest LC95 values for both laboratory and field strains of Aedes mosquitoes followed by Mn. indica, Ml. fasciculiflora and An. occidentale. Gl. renghas and Mn. indica were selected for the field evaluation with comparison to Abate and control. Gluta renghas stem extracts effectively reduced the number of eggs for dengue vectors in dry shaded conditions. Whereas, Mn. indica stem extracts were better in dry unshaded conditions. Gluta renghas leaf extract exhibited least survival rate of adults during both seasons (33.5%). Generally, survival rate of Aedes was observed to increase when the number of eggs reduced. Similarly, Mn. indica stem extract significantly prolonged the number of days of Aedes mosquito to reach adulthood (12.42+0.29 days) when compared to Abate in both the seasons (dry: F=8.35, df=5, P=0.000; wet: F=107.999, df=5, P=0.000). Fecundity of Aedes F1 generation was significantly reduced by Mn. indica stem extract in both seasons (dry: F=8.38, df=5, P=0.000, wet: F=4.87, df=5, P=0.000), while Abate
was effective only in wet shaded conditions (F=4.86, df=5, P=0.000). Reduction in fecundity consequently resulted in less egg hatchability rate. Highest Aedes egg hatchability was noticed for control (66.91%), whereas the lowest hatchability rate was observed for Abate (52.45%). Among the plant extract treatments, Mn. indica stem extract had the least percentage of eggs hatched (55.67%). Chromatographic analysis of the plants stem extract revealed quercetin and apigenin as the major group of compounds that might be responsible for causing the toxic activities to Aedes mosquito. Results from this study suggested that Gluta renghas and Mn. indica have the larvicidal and sublethal activities, particularly the stem extracts that can possibly compete with synthetic larvicides. It can be proposed as one of the alternative methods for the control of dengue vector which is environment friendly, target specific and low cost phytochemicals.
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The ovicidal and larvicidal effects from family Anacardiaceae , against the dengue vectors.