Volume 15 No. 01 & 02 2010http://dr.lib.sjp.ac.lk/handle/123456789/10062023-12-22T14:21:53Z2023-12-22T14:21:53ZPotential of Olax zeylanica (Olacaeceae) as a Botanical Insecticide for the Control of the Maize Weevil Sitophilus zeamais MotschulskyPerera, M.T.H.P.Karunaratne, M.M.S.C.http://dr.lib.sjp.ac.lk/handle/123456789/10162022-02-24T05:36:47Z2010-01-01T00:00:00ZPotential 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.
2010-01-01T00:00:00ZAedes Mosquito Survey within the Premises of University Sri Jayewardenepura to Determine Its Population Density and of Seasonal Shift in Relative AbundanceGunathilake, K.V.K.De Silva, B.G.D.N.K.http://dr.lib.sjp.ac.lk/handle/123456789/10152022-02-24T05:35:25Z2010-01-01T00:00:00ZAedes 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.
2010-01-01T00:00:00ZA Simplified Non Radioactive DNA Probe Technique for the Field Detection of Sibling Species A of the Anopheles culicifacies (Diptera: Culicidae) ComplexDe Silva, B.G.D.N.K.Hapugoda, G.P.G.M.D.Karunanayake, E.H.http://dr.lib.sjp.ac.lk/handle/123456789/10142022-02-24T05:36:48Z2010-01-01T00:00:00ZA 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.
2010-01-01T00:00:00ZTrends in the Incidence of Filariasis in Rapidly Urbanizing AreasGanegoda, N.C.http://dr.lib.sjp.ac.lk/handle/123456789/10132022-02-24T05:36:48Z2010-01-01T00:00:00ZTrends 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