author(s)
Sharanappa, Ashwani Kumar, Hadi Husain Khan and Ramkinkar Sahu

abstract
The present investigation entitled “Efficacy of certain insecticides against Rice stem borer Scirpophaga incertulas (walker).” was conducted during July, 2015 at Agricultural research farm, SHIATS, Allahabad. The occurrence of stem borer commenced from 34^th standard week (4^th week of August, 2015) with an average infestation per-cent 0.89 on 10 randomly selected hills per plot. The Stem borer infestation increased and gradually reached peak level of 8.92 % infestation at 40^th standard week (1^st week of October, 2015). Thereafter, declined trend was observed due to fall of maximum and minimum temperatures as optimum weather condition are decreasing. The two sprays were taken for the management of stem borer. Among two sprays, the data on the reduction per-cent of stem borer after two spray revealed that all the chemical treatments were significantly superior over control. Among all the treatments highest reduction per-cent of stem borer was recorded in Monocrotophos (T₁), followed by Chloropyriphos (T₂), Flubendiamid (T₃), Acephate (T₇), Cartap Hydrochloride (T₄), Imidacloprid (T₆), Fipronil (T₅). This was followed by Fipronil (T₅), which was recorded as least effective treatment within the insecticide treatment. The yields among the treatment were significant. The highest yield was recorded in (T₁) Monocrotophos (43.300 q/ha) followed by (T₂) Chloropyriphos (42.800 q/ha), (T₃) Flubendiamide (41.300 q/ha), (T₄) Cartap hydrochloride (42.00 q/ha), (T₅) Fipronil (39.300 q/ha), (T₆) Imidacloprid (41.500 q/ha), (T₇) Acephate (42.100 q/ha) as compared to control T₀ (27.000 q/ha).When cost benefit ratio was worked out, interesting result was achieved. Among the treatment studied, the best and most economical treatment was (T₁) Monocrotophos (1:3.24), followed by (T₂) Chloropyriphos (1:3.18), (T₃) Flubendiamide (1:3.07), (T₄) Cartap hydrochloride (1:2.93), (T₅) Fipronil (1:2.66), (T₆) Imidacloprid (1:2.88), (T₇) Acephate (1:1.25) as compared to control T₀ (1:2.19).