Tips on Controlling Golden Apple Snail
Unmanaged water supply in the farm can aggravate golden apple snail infestation. According to the book “Global Advances in Ecology and Management of Golden Apple Snail”, continuous source of water enhances snail growth and development, which results in rapid growth, reproduction, and dispersion of snails.
Hence, Mario dela Cruz of the Technology Management and Services Division of the Philippine Rice Research Institute (PhilRice) strongly emphasizes the importance of having a well-leveled field for this facilitates water management, which plays a big role in controlling movements and feeding activities of the snails.
He also recommends maintaining a shallow water depth of 1 cm-2 cm from transplanting because golden apple snail, locally known as golden kuhol, can move only when the depth of water is half or more of its shell height.
In direct-seedling, he said that pre-germinated seeds should be broadcast to saturated field with 1 cm water depth. Farmers should drain water from the field the day after broadcasting. Keeping the field drained for two to three weeks after seeding is the most effective way to avoid snail damage in direct-seeded areas. Farmers are also advised to prepare canalettes around bunds to attract golden kuhol.
However, when there’s 1 snail per 2 square meters in direct-seeded fields or 3 snails in transplanted fields, adds dela Cruz, farmers should prevent impending damage by practicing other non-chemical approaches such as the following:
• Place attractants along the edges of the dikes to make collection of snails easier. These include old newspapers and leaves of gabi, banana, and papaya.
• Raise strong and healthy seedlings for transplanting. Seedlings should be sturdy enough to discourage the snails from attacking them. They should be at the three-leaf stage or 21-25 days old before transplanting. Sturdy seedlings have erect, light green colored leaves and long, fibrous roots.
• Dry-plow after harvest as this enhances snail mortality. This method exposes the snails to the heat of the sun, which they cannot stand for a long time. It also makes them susceptible to predators such as rats.
• Herd ducks in rice paddies immediately after harvest up to the last harrowing for the succeeding crop. Handpicking is suggested to control large adult golden kuhol as these are not eaten by ducks. Collect also egg clusters, crush or leave the eggs in dry areas to desiccate and die.
When all options failed, farmers could apply moluscicide at label recommendation. Application should be done early in the morning or late in the afternoon when the snails are out and active.