This study evaluated the effectiveness of rotational and single insecticide applications against pea aphids on grass pea crops in the Dera and Fogera districts of Northwestern Ethiopia from 2021 to 2022. Experimental plots measured 2 m × 4 m and utilized a randomized complete block design with four replications. Insecticides profenophos, imidacloprid, λ-cyhalothrin and dimethoate were applied in rotation (P-I-L-D) and individually. It was found that all insecticide treatments reduced the numbers of pea aphids significantly. Treatment impacts on pea aphid populations, for example, were significant in Fogera in 2021 [F (5,18) = 34.924, p<0.001 in Week 2 and 93.250, p<0.001 in Week 3]. In 2022, similar trends were observed [Week 2: F (5,18) = 45.419, p<0.001 at Dera]. Grain yield also increased significantly with insecticide treatments, with the highest yields from dimethoate and rotational applications [Fogera 2021: F(5,18) = 48.154, p<0.001]. Cost-benefit analysis indicated that despite higher initial costs, treatments with dimethoate and rotational applications provided the highest net benefits due to their superior effectiveness in pest control and yield improvement. These findings underscore the importance of integrated pest management strategies, including rotational use of insecticides, to manage pea aphid populations effectively while enhancing grain yield and economic returns. In conclusion, implementing rotational insecticide strategies alongside Dimethoate application is recommended to sustainably manage pea aphids in grass pea crops.