Faerie Carleen Lucile L. Almira, William Benedict D. Delfin, Ayanna Benita Y. Galotera ( March 2012 )
Philippine Science High School Western Visayas Campus – Department of Science and Technology (DOST-PSHS WVC), Brgy. Bito-on, Jaro, Iloilo City 5000, Philippines
ABSTRACT
Golden apple snails, which are tropical and subtropical freshwater snails, commonly found in ponds, rivers and lakes, were imported to Philippines from South America to become a potential food source. Unfortunately, they became major pests in our crop industries today, decreasing the rice production and damaging crops (IRRI 2003).
In this study, the effects of organic (Cashew Nut Shell extract) and inorganic (Niclosamide solution) molluscicides on golden apple snails were observed. The objective of this study was to observe the behavior (escape behavior, feeding span, snail activity, and defense mechanism) of golden apple snails when exposed to Niclosamide and Cashew Nut Shell Crude Extract (CNSC Extract).
Cashew nutshells were gathered and were extracted in order to produce Ethanolic CNSC Extract. Niclosamide was weighed and prepared. 54 snails were gathered, distributed to different pails, and acclimatized. 12 pails were used in the setup. 6 pails were labeled as A (Niclosamide), B (CNSC Extract), or C (controlled). They were also labeled as Soil (qater with soil) or Water (water only). Snails labeled as FI (Food Intake) were placed equally in 6 separate pails labeled the same as the previous pails. After acclimatization, molluscicides were applied to their designated setups. Four parameters were observed, namely crawl speed, crawl distance, feeding span, mortality rate and mucus secretion for every 12 hours within 96 hours.
After analysis of data, it was found out that the snails are easily weakened by Niclosamide to the extent that they showed a mode measurement of 0 cm in crawl distance and 0 cm/s in crawl speed. While those snails that were exposed to CNSC Extract were observed to have higher activities (reaching a range of 8 cm in crawl distance and 0.07 cm/s in crawl speed) due to agitation from the extract. Results also consuming kangkong (1g/snail) for less than 96 hours. After 96h of exposure, 50% of the snails were found dead in the extract of CNSC. Therefore, the LC50 of CNSC is 22.81 ppm. The researchers were not able to observe the mucus secretion due to difficulties on identifying the mucus with water.