Identification and characterization of Coniella java']javanica causing leaf blight of kenaf (Hibiscus cannabinus) in Malaysia

Kenaf (Hibiscus cannabinus) has been widely grown in Malaysia because of its fiber content and economic value. In October 2019, blight symptoms were observed on kenaf leaves in a plantation in Chuping, Perlis, Malaysia. The symptoms appeared as irregular, yellowish to brownish water-soaked lesions, which expanded and are accompanied by pycnidial formation in concentric rings. At severe stage, the blighted leaves became dried and defoliated. This study aimed to investigate the causal pathogen of the leaf blight of H. cannabinus. Overall, 20 fungal isolates recovered from the blighted leaves of H. cannabinus were identified as Coniella javanica based on their morphological characteristics and DNA sequences of the internal transcribed spacer (ITS) region and translation elongation factor 1-alpha (TEF1-alpha) gene. Phylogenetic analysis of combined dataset of the ITS and TEF1-alpha, congregated the fungal isolates with the reference isolates of C. javanica (CBS 455.68 and GUE-29). The pathogenicity of C. javanica isolates was confirmed through pathogenicity tests. To our knowledge, this is the first report of C. javanica causing the leaf blight of H. cannabinus in Malaysia.