Syed Hassan Mehdi, Ayesha Qamar, Iram Khan and Priyanka Jacob
In the present study, ethyl acetate leaf extracts of two medicinal plants Ocimum tenuiflorum and Datura alba were investigated for mosquitocidal potential including larvicidal and Insect Growth Regulatory (IGR) activities against 4th instar Anopheles larvae. Leaf extracts showed moderate to high larvicidal activity at 24hrs and 48hrs continuous exposure while their IGR activity was observed after 72hrs. At 24hrs continuous exposure the Lc50 value of O. tenuiflorum and D. alba were 44mg/L and 46.00mg/L respectively. Similarly at 48hrs Lc50 values of O. tenuiflorum and D.alba were 33.6mg/L and 30.25mg/L. These values were based on the concentration mortality data along with their regression equation. The test of significance with 95% confidence limit was determined by log probit regression analysis for the study. Moreover, wide range of morphogenetic deformities was observed and recorded in different categories including larval pupal mosaic, abnormal pupae and pupal adult mosaic according to stage of metamorphosis when death occurred due to abnormal growth and moulting. The study is of great importance in formulation of an effective vector control strategy based on environmental friendly alternative (plant origin) insecticides.
