Study and application of molluscicides in Japan.

For several years after the First World War calcium oxide was the main compound used in the control of Oncomelania nosophora in Japan. This was generally replaced in 1944 by calcium cyanamide; since 1952 the prefectural authorities in areas of endemic bilharziasis have increasingly turned to the use of sodium pentachlorophenate as the molluscicide of choice. Applied at a rate of 5 g per m(2), this compound has been found to kill 70%-80% of snails per application.Laboratory and field experiments with calcium-arsenic compounds have been conducted in Japan and have indicated that these products have a relatively high molluscicidal effect; they have, however, not been used on a wide scale for snail control.