Management of the golden apple snail Pomacea canaliculata (Lamarck) in rice

Abstract

The golden apple snail Pomacea canaliculata (Lamarck) is a recently introduced rice pest in Asia. Its management is based on preventative and corrective methods emphasizing cultural and mechanical practices, with molluscicide as a measure of last resort. The planting method greatly influences the period of susceptibility to snail damage: wetbed-transplanted 20-day-old seedlings were less damaged than dapog-transplanted 13-day-old seedlings or direct-seeded rice. Seedlings ⩾ 30 days old were more tolerant of snail damage than younger seedlings. Drainage immobilizes snails. More preventative measures should be undertaken in high-risk (⩾ 2 snails m −2) than in low-risk (< 2 snails m −2) fields. Snails can be controlled in low-risk fields by employing one or two cultural methods. Dapog or direct-seeded methods would benefit from drainage and mechanical control (hand-picking). If cultural methods cannot be carried out, snails can be controlled with molluscicide at low dosage. High-risk fields, on the other hand, should be protected with a combination of cultural and mechanical methods. These methods can be substituted with low or high dosages of molluscicide. Molluscicide alone, however, requires a dosage of 0.5 kg a.i. ha −1, which most farmers cannot afford.