Clubroot Disease in South Asia: Distribution and Management Practices

ABSTRACT Clubroot, caused by the biotrophic protist Plasmodiophora brassicae , is a devastating root disease that affects all members of the Brassicaceae family. Significant progress has been made in understanding its occurrence, life cycle and management strategies. This disease has posed a considerable threat to producers and breeders globally, including South Asia. The disease has been reported in India, Nepal and parts of Bangladesh, Bhutan, Pakistan and Sri Lanka. The cool and moist climatic conditions in the northern Himalayan belt, combined with acidic soils and inadequate disease management systems, are key factors, particularly in areas of India and Nepal prone to clubroot outbreaks. Disease management strategies currently focus on soil amendments, the use of synthetic fungicides and fumigants and the application of resistant genotypes. However, limited research has been conducted on modes of disease transmission. Recent studies revealed that contaminated soil and infected seedlings are major contributors to the spread of the pathogen. Brassica crops such as B. juncea (mustard), B. napus (canola) and B. oleracea (cabbage) are particularly vulnerable. However, resistant cultivars like B. napus ‘Midas’ and B. oleracea ‘Big Sun 111’, ‘Nepa Star’ and ‘Kathmandu Local’, have been identified in India and Nepal, offering some potential for mitigating the disease. To combat clubroot effectively, there is an urgent need for integrated disease management strategies and the development of resistant genetic materials. These efforts should involve diverse stakeholders, including producers, industries, government sectors and academicians, aiming to advance the understanding of clubroot challenges and bridging critical research in South Asia.