Management of brinjal shoot and fruit borer (Leucinodes orbonalis Guen.) using selected bio-rational insecticides

Abstract

An experiment was undertaken to know the effectiveness of different bio- rational insecticides for controlling brinjal shoot and fruit borer (Leucinodes orbonalis Guenee) under field conditions during winter season 2017-18. The different treatments were Bioneem 1% EC (Azadirachtin 1000 ppm @ 1 mL L⁻¹ (T₁) Noclaim 5 SG (Emamectin benzoate) @ 1 mL L⁻¹ (T₂), Tracer 45 SC (Spinosad) @ 0.4 mL L⁻¹ (T₃), Suntec 1.8 EC (Abamectin) @ 1.2 mL L⁻¹ (T₄) and untreated control (T₅). The results revealed that the treatments Spinosad (T₃), Abamectin (T₄) and Emamectin benzoate (T₂) were effective to suppress brinjal shoot and fruit borer infestation in brinjal field. The rate of shoot infestation was observed 6.25% and 26.01% in Spinosad (T₃) treated and control plot, respectively. The lowest fruit infestation (6.98%) by number and (9.32%) by weight was recorded in Spinosad (T3) treated plot. Reduction rate of fruit infestation over control was 82.82, 51.19, 41.15 and 38.17% by number and 66.11, 43.75, 33.13 and 24.44% by weight in Spinosad (T₃), Emamectin benzoate (T₂), Abamectin (T₄) and Azadirachtin (T₁), treated plot, respectively. The yield in different treatments ranged between 22.02 and 32.52 t ha⁻¹. Healthy fruits yield increase over control varied from 19.36 to 85.46%, where the highest increase was found in Spinosad (T3) treated plot and the lowest in Azadirachtin (T₁). The highest adjusted net return and benefit-cost ratio (BCR) of Tk. 2,61,564 and 11.08, respectively were obtained from Spinosad (T₃) treated plot. The lowest BCR was 2.66 in Azadirachtin (T₁) treated plot. Among the four bio-rational inecticides Tracer 45 SC (Spinosad) showed the highest efficacy and it could be used against brinjal shoot and fruit borer in brinjal production.