Efficacy of quinoa (chenopodium quinoa) saponins against golden apple snail (Pomacea canaliculata) in the Philippines under laboratory conditions. http://dx.doi.org/10.1016/j.cropro.2007.08.010
Revista : Crop ProtectionVolumen : 27
Número : 3-5
Páginas : 553-557
Tipo de publicación : ISI Ir a publicación
Abstract
A novel product for managing Pomacea canaliculata, golden apple snail (GAS), containing quinoa saponins (Chenopodium quinoa), was evaluated under laboratory conditions for the protection of newly sprouted rice seeds. Experimental methods mimicked conditions
found in direct-seeded rice cultivation in the Philippines, but with a very high GAS density (90 snails/m2). Protection of newly sprouted seeds was directly proportional to saponin concentration in rice water. At 9 and 11 ppm saponin, seedling protection after 48 h against
GAS of different sizes was 93% and 95%, respectively. Seedling recovery after 5 d with 11 ppm saponin was 93%. This value declined to 0% and 4%, for the control (untreated) and niclosamide, a synthetic chemical molluscicide, respectively. The results indicated that
although niclosamide provides high efficacy against GAS (100% mortality, 24 h), it has a serious detrimental effect on rice seedlings. Mean GAS mortality with 11 ppm saponin was low at 24 h (45%), but increased to 94% at 48 h. Thus, seedling protection was probably
due to an almost immediate closure of the snails opercula when exposed to saponin solutions, followed by significant death rates within 24 and 48 h. The product also exhibits ovicidal effects, particularly with 15 d old egg masses; older egg masses were less susceptible to the product. The use of 11 ppm saponin slightly affected shoot growth, but this effect disappeared with time and the plants attained normal development. Saponin application rates at 10 ppm saponin in the rice water correspond to ca. 6 kg product/ha under cultivation conditions used in the Philippines. These results suggest that quinoa saponins may represent a commercially feasible environmentally benign alternative to synthetic chemical molluscicides against GAS, particularly in direct-seeded rice culture.