Investigation of the predation potential of different fish species on brown planthopper (Nilaparvata lugens (Stal)) in experimental rice-fish aquariums and tanks

A series of experiments was conducted in rice (Oryza salmi L)-fish aquariums and concrete tanks at Can Tho University, Vietnam, to investigate the feeding behavior and ability to control brown planthopper (BPH) (Nilaparvata lugens (Stal)) by fish. In the aquarium studies, fish species introduced were: (1) no fish (control), (2) common carp (Cyprinus carpio carpio L), (3) Nile tilapia (Oreochromis niloticus niloticus L), (4) climbing perch (Anabas testudineus Bloch), and (5) clown knife (Chitala chitala Hamilton). We found that C. carpio and O. niloticus mostly grazed on filamentous algae as well as periphyton on aquarium walls, bottom and rice tillers in water. They hardly grazed on BPH on the surface. On the contrary, A. testudineus mostly grazed on BPH on rice tillers above the water surface. C chitala spent a lot of time at the bottom corners of the aquariums without grazing on BPH. A. testudineus spent more time attempting to graze BPH, especially on rice tillers above the water surface as compared to C carpio and O. niloticus. This resulted in a higher number of BPH eaten by A. testudineus than by C. carpio and O. niloticus. As A. testudineus was the most promising predator of late instar nymphs and adult BPH in the aquarium studies, different sizes of this species were further tested in rice-fish concrete tank conditions at three development stages of the rice crop. All sizes of A. testudineus reduced the number of BPH. The small and medium A. testudineus were more efficient in reducing BPH than the larger ones. The present study suggests that A. testudineus can be incorporated in rice-fish fields as a part of biological control of BPH. (C) 2012 Elsevier Ltd. All rights reserved.