Synergism of Famoxadone and Cymoxanil in the management of Alternaria solani on potato (Solanum tuberousm L)

Abstract

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.