Journal of Entomology1812-56701812-5689Asian Network for Scientific Information10.3923/je.2006.136.142Nilaparvata lugens (Stal.)]]>RahmanM. A.JahanS. M.H.2200632A field experiment was conducted to investigate the effectiveness of different approaches of chemical and biological control against Brown Plant Hopper, Nilaparvata lugens (Stal.). The insecticide carbofuran 5G was applied at 50 and 75 days after transplanting in need base and this insecticide at 25 and 75 days along with Ripcord 10EC at 50 days after transplanting was also applied in schedule base. Natural biological control had no insecticide application and the control was largely due to the activities of naturally occurring predators and parasitoids. High level of predatory spiders and lady bird beetles were found in the fields of natural biological control compared to field of need and schedule base protection. The population of natural enemies was minimum at 60 days after transplanting in schedule base protection when population of brown plant hopper was also high. Need base protection approach was found to be superior in terms of control approaches than that of schedule base protection and naturally biological control approaches. The benefit-cost ratio (1.48) and grain yield (4.45 t ha-1) of need based protection were significantly higher than other control approaches.]]>Alam, S. and A.N.M.R. Karim,1977Nilaparvata lugens) a probable threat to rice cultivation in Bangladesh.]]>1977Anonymous,1992Anonymous,1997pp: 1-47pp: 1-47BBS (Bangladesh Bureau of Statistics),20002000BRRI (Bangladesh Rice Research Institute),19851985Chen, C.C. and R.J. Chiu,198161313Dhudhasamail T., P. Silapasorn and C. Shoiwtipl,1992172021Dyck, V.A. and B. Thomas,1979pp: 1-17.pp: 1-17.Fui Fen, Z. and L. Chuan Tao,1996224849Gomez, K.A. and A.A. Gomez, 19842nd Edn.,Pages: 704Pages: 704Heinrichs, E.A., W.H. Reessing, S. Valencia and S. Chelliah,1984Nilaparvata lugens (Homoptera: Delphacidae) and its predators.]]>1112691273Hibino, H.,19791298110Kamal, N.Q.,19981998Kiritani, K.,197924279312Mandal, S.L. and A.K. Somchoudhury,199456425428Murthy, M.M.K., D.V.S. Rao and K. Ramasubbaiah,19905200204Natarajan, K., M.S. Venugopal and S. Chelliah,1988132627Pan, D.Y. and X.M. Liang,199219234239Qi, B.,199042932Qiang, W., H. Lijuan, H. QiangLin, G.Z. Yan and X. XiaoLong,1995367Siddique, A.K.M.T.,19921992pp: 3345Vardhani, B.P. and K.T. Rao,2002137475Zhang, C.Z., L.F. Jiang and X.D. Fan,19883123127