Assessment of improved rice varieties against the infestation of brown planthopper (Nilaparvata Lugens Stal) (Hemiptera: Delphacidae)

Brown planthopper, ( Nilaparvata lugens Stal ) is the devastating pest of rice and distributed throughout the rice growing areas in worldwide. Though the resistant rice varieties have frequently been released globally, the seriousness of N.lugens is innumerable due to the coevolution strategy of N.lugens. It is also common to the Batticaloa district of Sri Lanka where the problem of N.lugens is recorded repeatedly. Thus the regular reevaluation of improved rice varieties is mandate for the proper management of N.lugens. Screening of sixty rice varieties including the varieties highly growing in the Batticaloa district was carried out at Rice Research and Development Institute, Batalagoda, Sri Lanka during yala 2017. The BPH resistance of different 60 rice varieties was assessed using conventional seed box test along with the resistant (Ptb 33) and susceptible check (Bg 380). The results showed that the rice varieties viz., Bg 94-1, Bg 366, Bg 357, Bg 374 and Bg 300 were mainly cultivated by the farmers at the Batticaloa district whereas almost all the varieties lost the unique characteristics in resisting the N.lugens. However Bg 357 and Bg 366 can fairly be recommended for the Batticaloa district as showed Moderately Resistant. Among the tested 60 rice varieties, 21 varieties viz., Bg 379/2, Bg 407H, Bg 359, Bg 304, Bg 305, Ld 371, At 306, At 405, Bg 403, Bg 310, At 354, At 309, At 311, Bg 745, Bg 38, H-4, H-10, Bg 369, H-7, Bw 453 and Bw 267-3 exhibited Moderately Resistant to BPH attack. These varieties can also be recommended to the Batticaloa district once after conducting a similar study at the Batticaloa district of Sri Lanka.