Trapping effect of inserting bamboo poles in the paddy fields on spawning of Pomacea canaliculata

Objective  To study different methods of inserting bamboo poles in paddy field on spawning ofPomacea canaliculata.

Method  Effects of four factors including position, distance, height and shape of inserting poles on trapping efficiency of P. canaliculata spawning were investigated.

Result  The bamboo poles inserted in paddy field could lure P. canaliculata to spawn on them. The number of egg masses tended to decrease successively from reviving stage, jointing stage to heading stage. At reviving stage with the best trapping effect, more than 50% egg masses were found on the bamboo poles which were 1 m from the paddy ridge, and the number was significantly higher compared with bamboo poles at other positions and rice straws(control)(P<0.05). The bamboo poles at 3 m distance from the paddy ridge and rice straws had the least numbers of egg masses, followed by the bamboo poles at 2 m distance from the paddy ridge. The trapping efficiencies for bamboo pole layouts with 100 cm distance and 30 cm distance between poles were 41% and 33% respectively, which were significantly higher than those for bamboo pole layout with 70 cm distance between poles and the control (P<0.05). The trapping efficiencies for bamboo poles with the tops being 30 and 50 cm high above water surface were 43% and 40% respectively, which were significantly higher than those for bamboo poles with the tops being 10 cm high above water surface and the control (P<0.05). There was no significant difference in the numbers of egg masses between circular-shaped and flat-shaped bamboo poles. After transplanting the rice, high trapping efficiency ofP. canaliculata spawning could be obtained by inserting bamboo poles at 1 m distance from paddy ridge, with 100 cm distance between poles and the tops being 30–50 cm high above water surface. Specially, at peak attack period ofP. canaliculata, bamboo poles inserted at 30 cm distance between poles could realize efficient trapping of egg masses.

Conclusion  Appropriately inserting bamboo poles in paddy field can help reduce the egg mass of P. canaliculata, hence reduce the reproductive rate of P. canaliculata and decrease the harm of P. canaliculata in practice. This research provides a new physical control approach of P. canaliculata.