Evaluation of Strobilurin and Triazole-Based Fungicides for Managing Foliar Blight in Large Cardamom in Taplejung, Nepal

Large cardamom (Amomum subulatum Roxb.) is an important spice crop in the Eastern Himalayas, including Nepal, but its productivity is severely affected by Colletotrichum Leaf Blight (CLB) caused by Colletotrichum spp. To manage this disease, a field experiment was conducted using a Randomized Complete Block Design (RCBD) with seven treatments and three replications. The treatments included three fungicides: Nativo (Tebuconazole 50% + Trifloxystrobin 25% WG), Syodia (Azoxystrobin 11% + Tebuconazole 18% SC), and Symister Top (Azoxystrobin 18.2% + Difenoconazole 11.4% SC): each applied at two different concentrations (1 g/ml per liter and a lower dose), along with a control. Before treatment, 40 leaves were randomly selected to assess initial disease severity. Fungicides were applied using a high-volume knapsack sprayer at 4 liters per plot. A second spray was done 15 days after the first when disease severity reached about 5%. All treatments followed recommended agronomic practices. Among the treatments, Symister Top at 1 ml/L was the most effective, reducing disease severity by 68.4%, followed by Nativo (61.7%) and Syodia (57.9%). The highest yield increase (22.5%) was also recorded with Symister Top. The efficacy is due to the systemic and translaminar action of the fungicides, though the risk of resistance development remains a concern. The study suggests that appropriate fungicide use can effectively manage CLB in large cardamom. However, integrating chemical control with other sustainable practices is essential for long-term disease management and environmental safety.