PREVALENCE AND DISTRIBUTION OF FOLIAR BLIGHT PATHOGENS OF WHEAT IN DIFFERENT AGRO ECOLOGICAL ZONES OF PAKISTAN WITH SPECIAL REFERENCE TO BIPOLARIS SOROKINIANA

摘要

During previous years blight diseases of wheat were considered to be of minor importance in Pakistan. However in Southern province of Sindh, where winter temperatures are warmer, Helminthosporium leaf spots (spot blotch) has been noted. During this study, surveys were conducted at seedling and booting stage of wheat during cropping season of 2004 to assess the foliar spot diseases in different agro-ecological zones of Pakistan including 55 locations (zone 6, 7, 9 & 10) at seedling stage and 101 locations (zone 5, 6, 7, 9, 10 and 11) at booting stage. The fungi isolated from the samples were identified as Alternaria alternata, Bipolaris sorokiniana, Curvularia lunata, and Drechslera spicifer. The most prominent fungus was Bipolaris sorokiniana, the cause of leaf blotch in wheat. A total of 37 isolates of Bipolaris sorokiniana were collected and identified as pathogenic to wheat. Tan spot causing fungus, Pyrenophora tritici-repentis was isolated only from the barley leaves but not from wheat.