Identification and Characterization of Pestalotioid Fungi Causing Leaf Spots on Mango in Southern China

Mango is an economically important fruit crop in southern China. However, leaf spots restrict the development of mango trees, reducing the yield and production. Pestalotioid fungi are one of the major agents causing leaf spots on mango. During 2016 and 2017, 21 isolates of pestalotioid fungi associated with leaf spots on mango leaves were collected from five provinces in southern China: Guangxi, Hainan, Yunnan, Guangdong, and Fujian. All 21 isolates were subjected to morphological characterization and DNA sequence analysis. The morphological data were combined with analyses of concatenated sequences of the ITS (internal transcribed spacer), TEF 1-α (translation elongation factor), and TUB2 (β-tubulin) for higher resolution of the species identity of these isolates. The results showed that these isolates belong to Neopestalotiopsis clavispora, Pestalotiopsis adusta, P. anacardiacearum, P. asiatica, P. photinicola, P. saprophyta, P. trachicarpicola, and Pseudopestalotiopsis ampullacea. Pathogenicity test results showed that all these species could cause symptoms. On detached mango leaves (cv. Tainong), early foliar symptoms on leaves were small yellow-to-brown lesions. Later, these spots expanded with uneven borders, turned white to gray, and coalesced to form larger gray patches. To our knowledge, this is the first description of N. clavispora, P. adusta, P. asiatica, P. photinicola, P. saprophyta, P. trachicarpicola, or Ps. ampullacea as causal agents for leaf spots on mango worldwide.