07-08-2013, 12:58 PM
Foliar Blight Disease of Onion in Jammu
ABSTRACT
Foliar blight is an important disease of onion responsible for causing major losses in its production. The current knowledge regarding the status of disease in Jammu region is quite rudimentary. Hence detailed investigations were carried out for two consecutive years to ascertain the status of the disease so as to provide a comprehensive database on which future disease management practices can be based. Ten locations in seven villages of Jammu district belonging to three Tehsils, viz., Akhnoor, Bishnah and R. S. Pura; ten locations in two villages of Tehsil Reasi of district Udhampur; two locations in village Thandapani of Tehsil Sunderbani of district Rajouri; and eight locations in five villages of Tehsil Hiranagar of district Kathua known for onion cultivation were selected for recording the observations. The disease development occurred at a rapid rate late in the growing season coinciding with the physiological ageing of the onion plants and build up of infected tissue where sporulation could occur. Pathogens observed to be associated with the foliar blight were Alternaria alternata, A. porri, A. tenuissima, Stemphylium vesicarium, Cladosporium allii - cepaeand Colletotrichum circinans. However, the relative occurrence of the pathogens varied during the cropping season. It was concluded that the disease responsible for causing foliar blight of onion in Jammu is not a single pathogen disease but a complex disease which is aggravated or reduced by the prevailing weather conditions.