Abstract

                                Two field experiments were conducted to assess the efficacy of fipronil 80 WG against stem borer and leaf folder in the paddy ecosystem at Tamil Nadu Agricultural University, Coimbatore. The results revealed that, the per cent reduction of leaf folder damage was recorded maximum in the plots treated with fipronil 80 WG at 100, 80 and 50 g a.i. ha-1 (77.96, 77.31 & 76.83 %, respectively over untreated control) and on par with standard check fipronil 5 SC @ 50 g a.i. ha-1 (76.37 %). Chlorpyriphos 20 EC @ 200 g a.i. ha-1 recorded 63.69 per cent reduction of leaf folder damage over untreated control. The stem borer damage was recorded minimum in fipronil 80 WG @ 100, 80 and 50 g a.i.ha-1 (3.43, 3.50 and 3.63 %, respectively over untreated check) followed by fipronil 5 SC @ 50 g a.i.ha-1 (3.76 %) and 40 g a.i.ha-1 (3.91 %) after two rounds of spraying. Whereas in untreated control stem borer damage recorded as 17.69 per cent. The grain yield was maximum in the plots treated with fipronil 80 WG @ 100 g a.i.ha-1 (4040 kg ha-1) which was on par with fipronil 80 WG @ 80 g a.i.ha-1 (4028 kg ha-1) and @ 50 g a.i.ha-1 (4017 kg ha-1). Fipronil 80 WG @ 50 g a.i. ha-1 recorded the highest percent reduction of leaf folder and stem borer damage in paddy with significantly increased yield and registered on par with treatments of its higher dose. Hence, fipronil 80 WG @ 50 g a.i. ha-1 is recommended for the management of leaf folder and stem borer in paddy ecosystem

Key words : Paddy; Stem borer; Leaf folder; Efficacy; Fipronil