Archivio Journal of Plant Pathology

Abstract:

Leaf blight symptoms consisting of dark brown lesions were observed on watermelon plants in seven districts or counties in Beijing municipality of China. A total of 64 Alternaria isolates were recovered and identified based on morphological characters and sequence analyses of rDNA-ITS regions and histone 3 genes. Amongst these isolates, Alternaria tenuissima was the most prevalent species representing 76.6% of the isolates, followed by A. alternata (23.4%). All isolates were divided into individual clades representing two species, A. tenuissima and A. alternata, according to phylogenetic analysis of histone 3 gene. Representative Alternaria isolates of the two species induced dark brown lesions on detached watermelon leaves, with disease incidence ranging from 44.4-83.3%. These results allowed the identification of the presence of Alternaria populations causing watermelon leaf blight for the first time in Beijing municipality of China.