Evaluation of Insecticidal Treatment Schedules for Managing Soil Pests and Enhancing Potato Yield

During the rabi seasons of two successive years (2021–2022 and 2022–2023), spanning November to February, the effectiveness of various insecticidal treatment regimes—T1 (spiromesifen), T2 (thiamethoxam), T3 (thiacloprid), T4 (imidacloprid), T5 (cartap hydrochloride), T6 (chlorpyriphos), as well as T7 (untreated control)—was assessed against Agrotis ipsilon (Hufner) on a single potato cultivar, Kufri Jyoti. The highest shoot damage was recorded in the untreated control plot, T7 (10.86–11.26%), while the lowest was observed in T1(5.86–5.89%), followed by T3(6.16-6.48%), T2(6.88–6.98%), T5(7.37–7.68%), T6(8.24–8.86%), and T4(8.66–9.37%). Tuber damage was minimal in T2 (13.25–15.36%) and peaked in the untreated control, T7 (34.19–43.40%). The lowest marketable yield of potato tubers (12.18–13.49 t/ha) was obtained from T7, while T2 produced the highest yield (27.81–28.38 t/ha), closely followed by T1 (26.21–26.72 t/ha). Among all treatments, T6 showed the least favorable cost-benefit ratio (1:1.41–1:1.58), whereas T2 recorded the most favorable ratio (1:2.55–1:2.57). Overall, T1 and T2 proved to be most efficient treatment schedules, significantly enhancing marketable tuber yield and reducing soil pest infestation compared to the control and other treatments.