Researchers from ICAR–Indian Institute of Spices Research (ICAR-IISR), Kozhikode have identified a new fungal disease that severely affected ginger crop during 2024 in parts of Kodagu District of Karnataka.
The disease, caused by the fungal pathogen Pyricularia spp., is a new threat to ginger cultivation. While Pyricularia is well known for causing blast diseases in monocot plants like rice, wheat, and barley, this is the first time it has been reported in ginger. The disease appears as yellowing of the ginger plant leaves, accompanied by black /dark olive-green spots in the early stages (Fig 1 & 2). Once the infection takes hold, it spreads rapidly and can cover the entire field within hours, leading to severe crop loss and plant death (Fig.3). Experts confirm that the rhizomes of the affected plants remain unaffected. The problem lies in the premature yellowing and drying of the leaves, which affects the proper formation of ginger rhizomes. As a result, farmers in Kodagu have experienced losses up to 30% in rhizome weight.
Climate Factors Contributing to Disease Spread
According to the researchers, the spread of the disease is largely driven by the specific climatic conditions prevailed in Kodagu. During the months of August and September, the region experienced dew fall in the mornings, which provides the ideal environment for the fungal pathogen to thrive and spread. This has led to the rapid spread of the disease throughout ginger fields in some parts of Kodagu, while crops in other parts of Karnataka and Kerala remain unaffected due to different environmental conditions. Research conducted by the team at ICAR-IISR Kozhikode and its Regional Station at Appangala indicated that the climatic conditions in Kodagu—particularly the dew fall during August and September—have created a favorable environment for the spread of the disease.
The research team at ICAR-IISR faced significant challenges when studying the disease, as samples collected were often dried by the time they reached the laboratory in Kozhikode. However, after months of investigation, scientists were able to confirm Pyricularia spp. as the cause behind the disease.
Recommended Control Measures
To manage the disease, scientists recommend the use of fungicides such as Propiconazole (Tilt) at 1ml/L or a combination of Carbendazim and Mancozeb at a ratio of 2 g/L. These fungicides can be used for the treatment of seed rhizomes for 30 min and before storage in well ventilated place. As a prophylactic measure Propiconazole (Tilt) or Tebuconazole (Folicur) @ 1ml/L can be sprayed four months after planting. If symptoms, such as black /dark olive-green pinhead spots surrounded by yellowing leaves, are observed, immediate fungicide application is advised to curb the rapid spread of the disease.
Given the fast-acting nature of Pyricularia, it is essential for farmers to act swiftly. The disease can spread over large areas in as little as 10 hours, with some affected fields located up to 20 kilometers apart.
Recommendation for Affected Farmers
Farmers whose crops have been affected by this disease are advised to temporarily refrain from cultivating ginger in the affected areas. The research team is conducting further studies to better understand the pathogen’s behavior and its environmental triggers.
