Snail-Killing Effects of Streptomyces 218 Powder

This study is aimed at finding out the snail-killing effects of Streptomyces 218 powder on Oncomelania hupensis snails which are the vectors or intermediate host of Schiltosoma Japonicum (intestinal schistosomiasis) in china the tests were carried out in the laboratory and on the field. The snail-killing effects of Streptomyces218 powder, isolated from snail habitat at Anchang Village of Anxiang country in China was tested using the immersion and spraying methods. The tests on the Oncomelania hupensis snails which are intermediate host of Streptomyces japonicum infection were carried out in the laboratory and in the field. The mean corrected snail mortalities of the immersion technique in the laboratory were 81.70 and 98.63% in 10 ppm of 218 solutions after 24 and 48 h, respectively. The mean corrected snail mortalities of the spraying tests in the laboratory were 82.90 and 87.90% at 3 and 5 days, respectively with 10 g/m2 218 powders. The snail-killing ability of 218 powders on the field determines by immersion and spraying methods were comparable to that of the chemical molluscicide-Niclosamide. The corrected snail mortality at 150 ppm of 218 powder (g/m2) and at 2 ppm of Niclosamide by immersion was 100% at the second time test after 24, 48 and 72 h. In the field spraying test, the mean corrected snail mortality at 100 ppm of 218 powders were 61.96 and 70.00% after 3 and 7 days of spraying respectively. At 2 ppm niclosamide, this was found to be 65.58 and 63.81%, respectively. The effective ingredients for the snail-killing are found to be located in the spore chains. Streptomyces 218 powder, although at higher concentrations, seems to be a promising mollusciciding biological agent. If developed further, this could compliment existing mollusciciding agents.