Management strategy for leaf blight of cabbage (Brassica oleracea var. capitata L.) in foothills of Nagaland

Cabbage (Brassica oleracea var. capitata L.) is a major cole crop in India. Cabbage leaf blight caused by Alternaria sp. is one of the serious foliar diseases responsible for low production and productivity. The disease is challenging to manage alone with fungicides or bioagents. Hence, the present study was undertaken to manage the disease effectively by utilizing bioagents, fungicides, and their combinations. The field trial was carried out in the Horticultural Research Farm, School of Agricultural Sciences, Nagaland University, Medziphema, Nagaland, during Rabi, 2022-2023 and in vitro evaluation of fungicides and bioagents conducted in the Department of Plant Pathology, School of Agricultural Sciences, Nagaland University, Medziphema, Nagaland. Management of leaf blight of cabbage was conducted with seven treatments (T1-T7). Among the different treatments tested in field condition, the minimum severity of Alternaria leaf blight (37.69%) coupled with maximum yield (23.39 t/ha) with a higher-cost benefit ratio of 2.72 were recorded in T6 (seed treatment with captan @ 3 g/kg + four foliar sprays of azoxystrobin 4.8% + chlorothalonil @ 0.25%). Among the six treatments, In vitro evaluation of bioagents Trichoderma sp. (TTV-2; T5) showed maximum inhibition with 69.44%, followed by Bacillus subtilis (CRB-7; T6) with 31.11% inhibition and among the chemical fungicides, azoxystrobin (amistar) showed the highest inhibition of 76.67% as compared to control. These treatments can effectively manage cabbage leaf blight disease and ensure sustained yields, particularly in the foothills of Nagaland.