Effectiveness of insect growth regulators for management of legume pod borer, Maruca vitrata F. in yard long bean

The legume pod borer, Maruca vitrata (Lepidoptera: Crambidae) is considered the most serious pest of yard long bean. An experiment was conducted in the field laboratory of the Department of Entomology, Bangladesh Agricultural University, Mymensingh during kharif season 2016 to evaluate the effectiveness of two commonly used insect growth regulators (IGR), burofezin and lufenuron with different doses and a widely used chemical insecticide nitro 505 EC as recommended dose for the management of legume pod borer. The treatments were arranged in Randomized Complete Block Design along with an untreated control with three replications of each treatment. The efficacy of the treatments was evaluated based on the percentage flower and pod infestation, percentage larval survivability and marketable pod yield. It was found that all the treatments were significantly effective against pod borer than the untreated control. The highest efficacy was found from the buprofezin among the treatments. Buprofezin @ 0.75 mL L−1 exhibited the best performance resulting 64.16 and 70.60% reduction of flower and pod infestation, respectively consequently providing 43.95% surviving larvae and 40.35% increase of pod yield with the benefit cost ratio1.47. This result was followed by buprofezin @ 0.5 mL L−1 and provided the results as 61.96%, 67.46%, 44.06%, 40.11%, and 1.48 flower infestation, pod infestation, surviving larvae, yield increase and benefit cost ration, respectively. Therefore, buprofezin @ 0.5mL L−1 might be recommended for the effective and economic management of legume pod borer in the yard long bean field.