Damage potential of the golden apple snail Pomacea canaliculata (Lamarck) in irrigated rice and its control by cultural approaches

Abstract

The damage caused by the golden apple snail in rice seedlings of various ages was assessed for different pest densities and water depth regimes. The experiments involved randomized complete-block and split-split plot designs with three replications. Water depth accounted for a higher proportion of the damage than seedlings' age and pest densities. At a water depth of >5.0 cm, direct-seeded rice and transplanted 21-, 30- and 40-day-old seedlings incurred damage of 100, 89.2, 59.7 and 46%, respectively. The susceptibility to snail damage decreased as seedling age increased. At a water depth of 5.0 cm, the pest caused insignificant damage to the 30- and 40-day-old seedlings. The same result occurred in direct-seeded rice and 21-day-old seedlings when the water was drained to a saturated soil moisture condition. Limited moisture conditions immobilized and prevented the pest from causing severe damage. This treatment reduced damage significantly, even when the pest density was five snails m−2. Dry direct seeding, which used a minimal amount of water in the early stages of growth, received 0% damage. Direct seeding with field draining to a saturated soil moisture condition, dry direct seeding, and transplanted 30- and 40-day-old seedlings with a water depth of 5.0 cm were tolerant to snail attack. The agronomic performance of these planting methods was not significantly different from conventional practices. The damage potential of the golden apple snail in rice depends on water depth >seedling age >pest density, in decreasing order.