http://dr.lib.sjp.ac.lk/handle/123456789/1006 2026-04-26T10:18:18Z http://dr.lib.sjp.ac.lk/handle/123456789/1016 Potential of Olax zeylanica (Olacaeceae) as a Botanical Insecticide for the Control of the Maize Weevil Sitophilus zeamais Motschulsky Perera, M.T.H.P.; Karunaratne, M.M.S.C. The possible use of leaf powder of Olax zeylanica in managing the maize weevil, Sitophilus zeamais was investigated in the present study. Mortality of one week old adults was obtained for five different doses each for their insecticidal effect (l.0, 2.0, 3.0, 5.0 and 7.5g) and fumigation toxic activity (2.0, 3.0, 5.0, 7.5, 10.Og) separately. In each bioassay, the mortality was recorded after 3, 6, 9, 12, 18, and 24 hours after they were exposed to different doses of the plant powder. The results of both bioassays revealed that the leaf powder of this plant elicited a very high insecticidal activity as well as fumigation toxic activity in S. zeamais weevils. Mortality effect of the powders on the weevils was found to be dose and time dependent. The observations indicated that the adult mortality increased with the increase of the exposure time and the dose. No mortality was observed 3 hours after the exposure of weevils to leaf powder at all doses. A high mortality rate was observed after 9 hours of exposure with all doses except for the lowest and alOO% mortality was recorded with 7.5g after 24 hours. Fumigation toxicity of plant powder against the weevils also gave similar results where no weevil deaths were observed at all doses of leaf powder after 3 hours of exposure. At the highest dose of 10.Og, 98% mortality was observed after 24 hours. The overall results imply the strong possibility of using leaves of Olax zeylanica as a potent bio-insecticide in protecting maize grains from S. zeamais infestations. 2010-01-01T00:00:00Z http://dr.lib.sjp.ac.lk/handle/123456789/1015 Aedes Mosquito Survey within the Premises of University Sri Jayewardenepura to Determine Its Population Density and of Seasonal Shift in Relative Abundance Gunathilake, K.V.K.; De Silva, B.G.D.N.K. The Premises of the University of Sri Jayewardenepura was surveyed in the month of May for possible breeding habitats of mosquitoes which were mapped out and the immature stages of collected were identified. Subsequently investigations were made by placing ovitraps within the University premises from June to November 2008, to determine the abundance of Aedes aegyp ti and Aedes albopictus detected during the previous survey in the month of May. An Ae.aegypti positive container was detected only once in all the indoor and outdoor container observed and no Ae.aegypti positive ovitrap was recorded during the study period .. The Ovitrap Index (01) for Ae.albopictus was calculated monthly. Breeding of Ae.albopictus was found in both indoor (Mean Monthly 01 =13.3) and out door containers (Mean Monthly 01 35.3). During the dry season the rainfall recorded a monthly range of 45.6 mm to 152.6mm. The larval population of Ae.albopictus remained low during this period with an 01 range from 0 to 12.5. However, during the rainy season which showed a monthly range of 294.9mm to 414.4mm, the 01 increased exponentionally (01 ranges from 13.3-80). In the month of September, Ae.albopictus were recorded in indoor ovitraps too (01=13.3), indicating its ability to replace the breeding places of Ae.aegypti, under certain environmental conditions. The monthly dengue incidence reported from the neighboring area declined in the month of August and started to increase again in the month of September. The ecological conditions in theses areas are very much similar to those within the University premises. The 01 values of dengue vector mosquito species could be utilized to indicate a potential increase in the dengue incidence. 2010-01-01T00:00:00Z http://dr.lib.sjp.ac.lk/handle/123456789/1014 A Simplified Non Radioactive DNA Probe Technique for the Field Detection of Sibling Species A of the Anopheles culicifacies (Diptera: Culicidae) Complex De Silva, B.G.D.N.K.; Hapugoda, G.P.G.M.D.; Karunanayake, E.H. Three cloned highly repetitive DNA sequences Rp36, Rp2l7 and Rp234 isolated from An. culicifacies Giles, sensu lato were developed as non radioactive DNA probes by using a biotinylated labeling and colorimetric detection system. These non radioactive DNA probes distinguish sibling species A from species Band C of the An. culicifacies complex in a dot blot hybridization assay using single mosquito DNA extracts diluted 50 fold. The biotinylated Rp217 probe was further assayed in a more simple procedure which involves the hybridization of blots prepared from squashed mosquito heads. This technique avoids the separate extraction of mosquito DNA and facilitates a number of samples to be processed rapidly while also allowing several field analyses to be carried out on one mosquito specimen. 2010-01-01T00:00:00Z http://dr.lib.sjp.ac.lk/handle/123456789/1013 Trends in the Incidence of Filariasis in Rapidly Urbanizing Areas Ganegoda, N.C. Incidence of Lymphatic Filariasis by microfilaraemic prevalence in a study area of Kalutara district, Sri Lanka has been analysed here. Trends of annual prevalence data are parsimoniously identified by least square method. There are no marked fluctuations in microfilaraemic prevalence at the initial stage of the whole study period from 1977 to 2005. Middle period is associated with fluctuations and continuous decrease is evident at the final stage. These prevalence patterns are interpreted in terms of adverse effects of urbanisation and also in terms of beneficial effects of the mass treatment programme. 2010-01-01T00:00:00Z