Abstract
The apple snail, Pomacea canaliculata (Lamarck), was introduced to Japan from South America as food for humans about thirty years ago. It is now a threat to the spread of direct-sown rice in Kyushu, southern Japan. Here we studied the use of a newly developed repellent paint containing fine copper powder to control the spawning of apple snails living in waterways. First, the repel-lent paint was applied to a concrete wall of the waterway in a narrow band (10 cm in width) just above the water surface. However, it was not effective due to the fluctuations of the water level. Then, the repellent paint was applied in a broader band (50 cm in width), and the effect was tested for three years. No egg masses were laid on the concrete wall painted with the repellent, indicating that the repellent controlled the spawning of apple snails. However, the density of the apple snails in the areas where the repellent was applied did not decrease compared to the areas without the repellent. The main reason could be that the size of the repellent areas was so small that the snails moved across the areas.
