Diaporthe limonicola causing leaf spot disease on Areca catechu in China.
The areca palm (Areca catechu L.) is an important economic crop in Hainan, China. In June 2018, symptoms of leaf spot were observed on nearly 20% of A. catechu in Qionghai, Hainan. At first, leaves exhibited small yellow spots; as symptoms progressed, the middle of the lesions appeared black with distinct yellow halos. Lesions were long oval, sometimes irregular with black to brown, small black spots and distinct yellow halos. As the lesions continued to expand, necrotic spots enlarged, gradually gray, and then combined to form larger necrotic areas. The causal pathogen was isolated and identified as Diaporthe limonicola based on morphological characteristics, molecular data (sequence analysis of the internal transcribed spacer (ITS) gene, β-tubulin (TUB) gene and translation elongation factor 1-α (TEF1) gene) and pathogenicity test. This is thought to be the first report of D. limonicola causing leaf spot on A. catechu in China.