Abstract
N-Tritylmorpholine (Frescon, WL 8008) is highly toxic to the intermediate-host snails of the Schistosomatidae. Molluscicidal concentrations range from 0.1 ppm to 0.5 ppm for 1-hour exposures and from 0.01 ppm to 0.05 ppm for 24-hour exposures. Under these conditions the compound is not toxic to snail eggs; recent work, however, shows that longer exposures are toxic. It has been successfully used to control snails in large-scale trials in several countries with very short exposures (4 ppm for 15 min), as well as in prolonged treatments (0.025 ppm for 16 days).
These treatments have remarkably little effect on other forms of aquatic life; plants, insects and the microfauna and flora are unaffected, and in certain circumstances it has proved possible to control snails without harming fish populations. A detailed study of the toxicology of N-tritylmorpholine in mammals has shown that it does not present any toxic hazards.
N-Tritylmorpholine can be formulated in a variety of ways, e.g., as emulsifiable concentrates, water-dispersible powders and granules, as well as some specialized types of formulations, such as baits and spreading oils. Laboratory and field studies have shown that environmental factors such as mud, light and vegetation have little effect on the performance of N-tritylmorpholine, but hydrolysis and loss of activity may occur in acid water.
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Selected References
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