Relative efficacy of selected insecticides to check rice yellow stem borer Scirpophaga incertulas (Walker) (Lepidoptera, Pyralidae) at Hooghly, West Bengal, India

Rice yellow stem borer (YSB), Scirpophaga incertulas Walker is one of the major destructive insect pests rendering huge crop damage. Nine insecticide formulations, either solely or in combinations were applied in the rice (var. Lalat) field for two consecutive seasons during 2019-2021 to assess their efficacy to suppress YSB population and to stabilize yield. The combination of flubendiamide (480 SC) @80 g a.s.ha-1 on 45 DAT and deltamethrin (1%) + triazophos (35%) @300 g a.i.ha-1 on 80 DAT, treated the rice crop, recorded minimum YSB incidence (4.14 egg clutches, 4.78 larvae and adults 3.17/5 hills) and damage (2.12% dead hearts (DH) and 1.47 white ear (WE). This treatment gave significantly higher grain yield (3.63 t ha-1), an increase of 45.78 per cent over control. The incidence (12.21 egg clutches, 14.12 larvae and adults 11.76/5 hills) and crop damage (14.83 DH and 11.10% WE) was maximum in the treatment, neem seed kernel extract (5%) @50 ml L-1 at 15 day intervals after transplanting and neem leaf extract (5%) @7 ml a.s. L-1 on 35, 50, 65 and 80 DAT, resulting in minimum yield (2.88 t ha-1). Other combinations of insecticide application gave variable results.