Status of Fusarium wilt in India

With an annual production of 27 million tonnes, India is the world largest producer of banana. Many pests and diseases cause huge economic losses to the farmers. Among these, Fusarium wilt caused by Fusarium oxysporum f. sp. cubense (Foc) is one of the most important production constraints. The disease is widespread in almost all banana-growing states of India, with disease severity as high as 80-90% in some states where susceptible cultivars are grown on large areas. The important groups of banana severely affected by this disease are: ‘Silk’ (AAB), ‘Ney Poovan’ (AB), ‘Pisang Awak’ (ABB), ‘Pome’ (AAB), ‘Bluggoe’ (ABB) and ‘Monthan’ (ABB). Recently, a virulent strain of Foc affecting Cavendish types has been identified. In addition, ‘Mysore’ (AAB) which was hitherto tolerant to Foc has recently been found infected by Foc vegetative compatibility group (VCG) 0124/0125. A diversity analysis was carried out on 200 Foc isolates collected from different parts of India, to find out the various pathotypes in Foc by VCG analysis. The analysis indicated the presence of six different VCG groups. Ddiversity analyses of Foc, pathogen-host resistance, biological control using endophytes, standardisation of a diagnostic kit for the identification of the pathogen present in the soil and in the plant are the major areas of Foc research in India. Recently, molecular markers for the identification of pathogenic Fusarium present in the soil as well as in planting material have been developed. No effective control measures are available except growing of resistant cultivars. Recently, the National Research Centre for Banana (NRCB) has identified an effective fungal antagonist, Trichoderma viride, which has effectively controlled the soil-borne inoculum of the Fusarium pathogen. A mass-production protocol at farm level using banana farm waste has been developed for the cost-effective management of the disease. Activities for the effective management of this disease are discussed.