Survey and Surveillance of Twister Disease of Onion In Karnataka Patil Suresh*, Nargund V.B.*, Gurudath H., Dharmatti P. R., Ravichandran S. Department of Plant Pathology, College of Agriculture, University of Agricultural Sciences, Dharwad, 580 005, Karnataka, India *email: sureshpatil007@gmail.com
Online published on 23 December, 2016. Abstract A roving survey was carried out to know the incidence and severity of twister disease of onion during 201112 and 2012–13 in major onion growing areas of Karnataka. The study revealed that severity of this disease varied from locality to locality. The severity of disease was also dependent on cropping pattern, environmental conditions prevailing in different localities and genotype grown. Among the districts surveyed the highest per cent disease index(PDI) of twister disease of 24.05 and 29.37 per cent was observed in Uttar Kannada district, 2012 and 2013 respectively. There was no/negligible amount of disease was observed in Bellary and Raichur district. Symptoms of the disease noticed were viz., twisting of leaf and neck with blight as well as dieback (anthracnose). Scanty root system with galls, discoloured containing fungal growth. With respect to rain fed and irrigated conditions during survey, it revealed thatthere was no difference in severity. As for as predominance of pathogens is concerned Colletotrichum spp. recoded in 78 fields followed by Fusarium sp. 50 fields and in combination of both Fusarium spp and Colletotrichum spp with 34.5 fields whereas Sclerotium sp. (16%) Meloidogyne spp. (6%) was also observed. With reference to genotype the Arka Kalayan has shown infection in the range of 25 to 65 per cent followed by Local varieties with a range of 0 to 55%. Whereas less incidence was observed in private hybrids with a range of 5 to 10 per cent. Top Keywords Twister disease, Onion, Survey, Surveillance, Fusarium spp, Colletotrichum spp, Sclerotium sp, Meloidogyne spp. Top |