Browsing by Author "Ekanayake, E.M.A.U."

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    Effect of Selected Plant Aqueous Extracts on Controlling of Brown Plant Hopper (Nilaparvatalugens), Paddy Bug (Leptocorisaoratorius) And Rice Leaf Folder (Cnaphalocrocismedinalis)
    (Uva Wellassa University of Sri Lanka, 2018) Ekanayake, E.M.A.U.; Sarathchandhra, S.R.; Weerawasnsa, A.N.R.; Kaliyadasa, P.E.
    Cnaphalocrocismedinalis, Nilaparvatalugens and Leptocorisaoratorius are majorinsect pests in rice which cause a considerable loss of annual rice yield. Synthetic pesticides are widely used to manage pest attacks in rice cultivations in Sri Lanka. Compared to the synthetic pesticides, plant based extracts are usually safer to the environment and humans. This study was conducted to test the bio-efficacy of four selected plant extracts vizAzadirachtaindica (Neem), Annonamuricata (Anona), Calotropis gigantean (Wara) and Lantana camara (Gadapana) against Cnaphalocrocismedinalis, Nilaparvatalugens and Leptocorisaoratorius and to compare the insecticidal activity of the commonly used synthetic pesticide with plant extracts against the above-mentioned pests. Aqueous extractions of these plant species were made in three concentrations. i.e.10 g/100 ml, 50 g/100 ml and 100 g/100 ml.Tested synthetic pesticides against Cnaphalocrocismedinalis, Nilaparvatalugens and Leptocorisaoratorius were Tebufenozide (20 m1/101), Thiamethoxam (5 g/16 1) and Carbosulfan (560 mllac) respectively. The experiment was laid out in Complete Randomized Design with fourteen treatmentsincluding a controlwith three replicates for each pest. Ten second instar larvae of Cnaphalocrocismedinalis, fifteen adult of Nilaparvatalugens and thirty adult of Leptocorisaoratorius were taken as experimental units. Bioassay methodology was used. Mortality percentage at 96 hours after application of each extract was recorded. It was concluded that in controlling of Cnaphalocrocismedinalis, Nilaparvatalugens and Leptocorisaoratorius, the most efficient plant extracts were Annonamuricata (50 g/100 ml), Azadirachtaindica (50 g/100 ml) and Calotropis gigantean (10 g/100 ml) respectively.