EFFECT OF SOME INSECTICIDES AGAINST MAJOR INSECT PESTS OF BLACKGRAM

Abstract

The experiment was conducted during the period from March to May, 2016 at the Research Farm of Sher-e-Bangla Agricultural University (SAU), Dhaka to study the effect of some insecticides against major insect pests of blackgram. Blackgram variety BARI mash-3 (Hemantoo) was used as planting materials for the study. The experiment consists seven treatments as T1: Admire 200 SL (Imidacloprid) @ 0.5 ml/L of water at 10 days interval; T2: Voliam Flexi (Thiamethoxam + Chlorantraniliprole) @ 1 ml/L of water at 10 days interval; T3: Nitro 505 EC (Chlorpyrifos + Cypermethrin) @ 2.0 ml/L of water at 10 days interval; T4: Casper 5 SG (Emamectin Benzoate) @ 1 gm/L of water at 10 days interval; T5: Dimethoate 40 EC (Rogor 40 L) @ 2 ml/L of water at 10 days interval; T6: Neem oil @ 3 ml + Trix @ 5 ml at 10 days interval and T7: Untreated control. The experiment was laid out in Randomized Complete Block Design (RCBD) with three replications. Data on the incidence of different insect pests on blackgram, pod infestation, different yield attributes and yield were recorded and significant variation was recorded for different treatment. The lowest number of stem fly larvae/pupae per plant (0.33) was found from T1, while the highest (4.67) from T7. The lowest number of jassid per 10 leaves (1.22) was found from T3, whereas the highest (9.39) from T7. The lowest number of whitefly per 10 leaves (1.19) was found from T3, while the highest (7.77) from T7. The lowest number of jute hairy caterpillar per plant (1.07) was found from T4, while the highest (3.87) from T7. The lowest number of stink bugs per 10 leaves (1.27) was found from T4, while the highest (5.27) from T7. At early pod development stage, the lowest infestation (2.16%) was recorded in T2 treatment, whereas the highest infestation (12.04%) in T7 treatment. At mid pod development stage, the lowest infestation (3.09%) was recorded in T2 treatment, while the highest (13.69%) in T7 treatment. At late pod development stage, the lowest infestation (3.96%) was recorded in T2 treatment but the highest (14.70%) in T7 treatment. The highest yield per hectare (1.75 ton) was recorded in T4 treatment, whereas the lowest (1.18 ton) in T7 treatment. The highest benefit cost ratio (2.13) was estimated for T3 treatment, while the lowest (1.45) from T5 treatment. It was revealed that Nitro 505 EC (Chlorpyrifos + Cypermethrin) @ 2.0 ml/L of water at 10 days interval was more effective against the major insect pests of blackgram.