UPV Theses and Dissertations
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Item Molluscicidal activity of tabaco dust against the brackishwater pond snail Telescopium telescopium (Gastropoda: Potamididae)Azucena, Paulene C. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2003-04)Telescopium telescopium, a molluscan potamidid snail thrives in the muddy substrates of brackishwater ponds in the Philippines. It occurs in considerable numbers but uncontrollable increases in its population poses serious threats to pond production. Tobacco dust is considered as a potential biomolluscicide that is able to control pond snail infestation. A short-term bioassay was conducted to know the effectiveness of tobacco dust as a molluscicide against T. telescopium by determining its median lethal concentration (LC50) after a period of 96 hours. Twenty-five telescope snails were subjected to varying concentrations of tobacco dust, from 0 to 1.0 kg/L at 0.2-kg increments. Three replicates were done for every treatment. Counting of dead snails was done after 48 and 96 hours of exposure. Snails exposed to varying concentrations of tobacco dust exhibited several defense mechanisms such as avoiding the toxic solution by crawling out of the area, closing their operculum and retracting their bodies toward their shell. Highest snail mortality was observed at the 1.0-kg/L treatment. After the 96-hr. exposure time, the concentration of tobacco dust that proves to be lethal to 50% of the snails was computed to be 0.5849 kg/L. Indeed, tobacco dust is an effective molluscicide against brackishwater pond snails, particularly T. telescopium.Item Molluscicidal effect of quicklime, CaO on golden snail (Pomacea canaliculata)Baibado, Joewel Tarra (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1998-03)The golden snail (Pomacea canaliculata) is presently a major pest of rice in lowland and rainfed areas through out the Philippines . The problem of golden snail infestation in rice farming system includes damage to the rice plants, rice yield losses, additional expense, side effects of chemicals and destructive effect on native snails . The study was conducted to evaluate the molluscicidal effect of calcium oxide for the control of golden snails in farmlands and to determine the 96hour LC50 in order to know the lethal concentration of calcium oxide to golden snails. Calcium oxide was found to have a molluscicidal activity on golden snails The golden snails were exposed to different concentrations namely. 100 ppm. 200 ppm. 300 ppm .400 ppm. and 500 ppm Remarkable lethal effects of calcium oxide (p<0.05) has been found in 4(H) and 500 ppm concentrations which has reached 60-100 % after the 96 hour treatment. The 96-hour LC50 within the 95% confidence interval was 322.02 ppm as computed Calcium oxide is safe on rice when used as a molluscicide It performs dual function as fertilizer/soil stabilizer and molluscide. These dual effects are very significant because it means big savings on the part of the rice farmers. Considering the prevalence of this pest, farmers spend much on molluscicides and their application. With calcium oxide, the farmer has a molluscicide and soil stabilizer in one application.