Before a line is released to farmers, it undergoes rigorous evaluation of its reaction to various biotic and abiotic stresses across seasons and locations. However, rice varieties have never been evaluated for resistance to golden apple snail (GAS), Pomacea canaliculata, because all rice varieties were assumed to be equally susceptible to this pest. Rice is at risk from GAS during the first 15 d after transplanting. Newly transplanted rice seedlings are devoured from the base. After complete removal of leaves and leaf sheaths, the plant cannot regenerate. The degree of damage depends on GAS density and size.
The rapid spread of GAS and the consequent losses make GAS management urgent. Commercial synthetic molluscicides are widely misused by rice farmers in an attempt to control GAS. To reduce the hazards of pesticide misuse and cost of control, identifying rice varieties less prone to GAS damage is important. Thus, this study examined rice varieties released by the Philippine Seed Board (PSBRc) to identify those that are less prone to GAS damage. An initial study was conducted under free-choice tests at the PhilRice-Central Experiment Station (CES) farm (longitude 120° 56′ E; latitude 15° 45′ N; altitude 48 m above sea level). Thirty two PSBRc varieties were planted in a well-leveled field. IR64 served as a check. GAS were handpicked several times to remove resident GAS.