EFFICACY OF BIO-RATIONAL AND MICROBIAL INSECTICIDES AGAINST FRUIT BORER (HELICOVERPA ARMIGERA HUB.) ATTACKING TOMATO

ABSTRACT: The experiment was carried out during winter 2019 in the field of Agricultural Training Institute, Sylhet, Bangladesh to find out the effective ecofriendly insecticides to control fruit borer Helicoverpa armigera Hub. attacking tomato plants. The study was conducted with three treatments viz., Bacillus thuringiensis @ 2.0 mg L-1, Spinosad 45 SC@ 0.4ml L-1, Abamectin 1.8 EC @ 1.2 ml L-1 of water and untreated control. Results revealed that the number of healthy fruits increased by 72.85% over control due to spraying of Spinosad 45 SC and it was followed by Bacillus thuringiensis (32.78%) and Abamectin 1.8 EC (26.82%). The highest number of healthy fruits (274.00) was harvested from Spinosad 45 SC treated plot and the lowest number (100.6) from untreated control plot. The yield in different treatments ranged from 12.43 -17.58 t ha-1. The highest adjusted net return (Tk. 225800.70) and BCR (Tk. 8.74) were obtained from Spinosad 45 SC treated plot. The second highest BCR of 8.70 was calculated from Bacillus thuringiensis (Bt) treated plot and the lowest BCR of 5.02 was found in Abamectin 1.8 EC treated plot. All the treated insecticides reduced the infestation of fruit borer, but Spinosad 45 SC was found most effective.

Keywords: Helicoverpa armigera, Solanum lycopersicum, yield, benefit-cost ratio, biorational and microbial