Vol. 9, Special Issue 11, Part D (2025)

Potato (Solanum tuberosum L.) is the third most important food crop globally, yet its productivity is severely constrained by early blight caused by Alternaria solani, which can result in 5-50% yield loss under favorable conditions. The present study evaluated the efficacy, phytotoxicity and economic feasibility of the fungicide mixture Famoxadone 16.6% + Cymoxanil 22.1% SC against early blight in potato under Nilgiris agro-climatic conditions during Kharif 2023 and Rabi 2023-2024. Field experiments were conducted in a Randomized Block Design with seven treatments, including different dosages of the test fungicide, standard checks (Azoxystrobin and Mancozeb) and an untreated control. Results revealed that Famoxadone 16.6% + Cymoxanil 22.1% SC at 600 ml/ha (T4) recorded the lowest Percent Disease Index (8.51% in Kharif and 9.00% in Rabi) and the highest tuber yield (256.30 q/ha and 260.30 q/ha, respectively), significantly outperforming standard checks. Growth parameters such as shoot length, root length, tubers per plant and tuber weight were also maximized in T4, followed by T3 (500 ml/ha). No phytotoxic effects were observed at any dosage. Economic analysis confirmed the superiority of T4, which achieved the highest benefit-cost ratio (2.09 in Kharif and 2.03 in Rabi). These findings establish Famoxadone 16.6% + Cymoxanil 22.1% SC as a safe, effectiveand economically viable fungicide mixture for managing potato early blight.