Leaf blight of sunflower caused by Alternaria spp. occurs frequently in the Beijing municipality of China. A total of 482 Alternaria isolates were obtained from sunflower leaves with typical dark fleck symptoms sampled from 13 different districts in the Beijing municipality in 2014. Morphological observations and sequence analyses of the rDNA-ITS region and the histone 3 gene revealed that two Alternaria species, A. tenuissima (86.5 frequency) and A. alternata (13.5 frequency), were associated with the disease. Four isolates of A. tenuissima and six of A. alternata were pathogenic to sunflower leaves with disease incidence and disease index ranging from 50-100 and 16.7-33, respectively. This is the first comprehensive examination of the involvement of Alternaria species in leaf blight of sunflower of Beijing, China.
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