The golden apple snail in the rice fields of Asia
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Rice fields in the Philippines
devastated by the snail
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The golden apple snail was introduced from
Florida and Latin America to Taiwan (Province of China) and
the Philippines in the early 1980s by private snail farmers
hoping to reap big profits exporting snails to Europe. Easy
to rear and fast breeding, the snail's high protein content
also apparently made it an ideal supplement to the
low-protein diet of the rural poor. Unfortunately, the
snails were not a success with consumers, and although they
were initially expensive, their market value soon plummeted.
The escaped and discarded snails quickly spread through
waterways and irrigation canals. When they reached the rice
fields they found an ideal habitat, feeding by night and at
dawn on young succulent plants such as newly transplanted
rice crops and weeds. With only a few natural enemies to
constrain them, the snails rapidly developed into a serious
pest in many areas of cultivated rice land in Asia. Their
fast growth and reproduction - females lay egg masses of up
to 500 eggs once a week - leads to population levels that
can destroy entire rice crops.
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Golden
apple snail egg masses: newly laid (right) and near
to hatching (left)
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Golden apple snails feeding on
azolla
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Photos by Dr M. Halwart (by kind permission of
Margraf Verlag, Weikersheim, Germany)
30 April 1998
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