Reaction of local Rice varieties and bio-efficacy of insecticides against yellow stem borer in Manipur

Among the cultivars/varieties, WR-11-4 suffered least injury, however, it gave the lowest grain yield with 2.33t/ha. The rice variety Phouoibi gave resistant reaction in the vegetative stage and susceptible in the reproductive stage against the pest but recorded the highest average grain yield of 4.62t/ha. The grain yield of Phouoibi was comparable with KD-5-2-8 (4.57%t/ha), Sanaphou (4.49t/ha), RCM-9 (4.47t/ha), RCM-10 (4.45t/ha), Tamphaphou (4.44t/ha) and KD-5-3-14 (4.39t/ha) although these cultivars/varieties also recorded higher infestation of the pest. Among the insecticides, nuvacron (monocrotophos 36 WSC) was observed as the most effective chemical with minimum stem borer infestation (0.50%DH & 0.27%WEH) and maximum grain yield of 6.30t/ha. Confidor (imidacloprid 17.8EC) and roket (profenophos 40% + cypermethrin 4%) was comparable with nuvacron in terms of reduction in stem borer infestation and yield. The botanicals, nimbecidine (azadirachtin 0.03%) (5.30t/ha), calpaste (5.01t/ha) and Cal-10 (4.81t/ha) gave significantly higher grain yield than untreated control (4.32t/ha).