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Endod, a potential natural pesticide for
use in developing countries
Legesse Wolde-Yohannes
Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
In recent years, economic and ecological factors have forced many developing
countries to consider alternatives to synthetic pesticides, such as
the natural molluscicides found in local plants. Since the early 1930s,
more than I 071 plant species have been tested: 48% contained substances
toxic to snails, the intermediate hosts of schistosomiasis, some of them as
potent as manufactured molluscicides. Endod is one of the most promising
plant molluscicides because of its high toxicity to the snails, low toxicity
to mammals, stability under various environmental conditions, biodegradability,
widespread distribution in tropical Africa, and potent ialfor
large-scale cultivation. Results of the first longitudinal studies on the
cultivation, yield, and molluscicidal potency of endod types 3, 17, and 44
indicate that they can be cultivated successfully and that type 44 is most
suitable for schistosomiasis control.
Plant-derived molluscicides are a reasonable option for the control of schistosomiasis,
particularly in developing countries with agricultural economies,
where parasitic disease affects at least 200 million people (Adams 1986; Kloos
and McCullough 1987; Legesse and Kloos 1990).
Since the early 1930s, 1 071 plant species have been tested for molluscicidal
activity (Kloos and McCullough 1987). Few, however, have proven to have the
characteristics necessary for widespread use: low toxicity, water soluble,
common, easy to cultivate, and consistently high molluscicidal potency
(Legesse and Kloos 1990). If other uses could be found for these few species
their value would increase (Adams 1986; Legesse et al. 1986; Kloos and
McCullough 1987; Kloos et al. 1987; Legesse and Kloos 1990).
Commercially available chemical molluscicides are expensive in view of the
large quantities required for control programs on a regular basis and currency
constraints faced by developing countries (Lambert et al. 1985). Compounds,
such as copper sulfate and sodium pentachlorphinate, have been used as
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