Evaluation of Biological Approaches for Controlling Shoot and Fruit Borer (<i>Earias vitella</i> F.) of Okra Grown in Peri-Urban Area in Bangladesh

Irrational applications of insecticides on vegetable crops are very common in Bangladesh, resulting in harmful consequences for the environment and human health. Therefore, a study was conducted to evaluate the efficacy of biological and botanical insecticides on okra shoot and fruit borer grown in open fields. Four insecticides were used in this study, namely <i>Bacillus thuringiensis</i> (Bt), Spinosad 45 SC, Abamectin 1.8 EC, and Azadirachtin 1% EC an untreated control. The experiment used a randomized complete block design (RCBD) with three replications. The results showed that the rate of shoot infestation was the lowest in the Spinosad-treated plot (3.80%), and the highest was in the control (20.67%). The lowest fruit infestation (3.56%) was recorded in the treated plot of Spinosad. The rate of reduction of fruit infestation over control was 80.69, 60.14, 56.45, and 55.58% in the plots treated with Spinosad, Bt, Azadirachtin, and Abamectin, respectively. Consequently, the Spinosad-treated plot attained the highest yield (8.65 t ha⁻¹), which was followed by the plots treated with Azadirachtin (6.74 t ha⁻¹), Bt (6.28 t ha⁻¹), and Abamectin (6.12 t ha⁻¹). The highest net return and benefit–cost ratio (BCR) were 542.36 US$ and 2.64, obtained respectively from the Spinosad-treated plot. The second highest BCR (1.70) was obtained from the Azadiratin-treated plot, and the lowest BCR (1.18) was recorded in the Abamectin-treated plot. Therefore, the studied insect management practices could be incorporated to attain higher yields and economic benefits for growing okra in Bangladesh.