Abstract
<title>Abstract</title> <p>Biotic and abiotic constraints present significant challenges to common bean production. In the study area, the legume pod borer (Maruca vitrata) is the primary insect pest affecting this crop. To evaluate the effectiveness of various synthetic insecticides combined with improved cultivars against the pod borer under field conditions, a field experiment was conducted in the Adola Rede district of the Guji Zone during the 2023–2024 cropping season. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications. The treatments consisted of two bean cultivars (Ibado and Rori) and three insecticides (Diazinon 60% EC, Profit 72% EC, and Helerate 5% EC). The results revealed that while the interaction effect between cultivars and insecticides was not statistically significant while the main effect of the insecticides varied significantly. In contrast, the main effect of the cultivars showed no significant differences. Helerate achieved the highest larval reduction (97.65) and the lowest pod infestation (21.73%), whereas Profit resulted in the lowest larval reduction (78.38) and higher pod infestation (32.28%). Although the number of pods per plant did not differ significantly among treatments, significant variations were observed in seed yield and hundred-seed weight (HSW). The application of Helerate produced the highest seed yield (1780.38kg/ha) and HSW (56.00gm), which was statistically comparable to Diazinon (1601.56kg/ha, 53.08gm) respectively. Conversely, the unsprayed Ibado control recorded the lowest yield and HSW (786.46kg/ha, 39.50gm), which was statistically similar to the unsprayed Rori control (923.61kg/ha, 42.00gm) and the Profit treatment yield (1109.37kg/ha). Economic analysis further indicated that applying Helerate yielded the highest marginal rate of return (3496). Consequently, Helerate is recommended as the most effective insecticide for managing the legume pod borer in common bean production within the study area.</p>