Identification of the pathogen responsible for tea white scab disease

Abstract

AbstractTea white scab disease commonly occurs in high‐altitude tea‐growing areas worldwide. Both Elsinoe leucospila and Phyllosticta theaefolia have been reported as the pathogen responsible for this disease. To conclusively identify the causative agent, samples were collected from plants infected with tea white scab disease in high‐altitude tea gardens in southern China. Fungal isolates obtained from the infected material were identified based on morphological characteristics, comparisons of ITS, 18S rDNA, RPB2 and LSU sequences, and pathogenicity tests. Both Elsinoe sp. and Phyllosticta sp. were isolated from the collected samples with rates of 6% and 35%, respectively. On potato dextrose agar medium, Phyllosticta sp. grew faster and sporulated more than E. leucospila. However, only E. leucospila caused symptoms similar to those of tea white scab disease. In contrast, Phyllosticta sp. infections resulted in large necrotic spots. Therefore, E. leucospila appears to be the pathogen responsible for tea white scab disease, whereas Phyllosticta sp. is a hyperparasitic fungus that infects the diseased plant tissue. The high isolation rate of Phyllosticta sp. due to its rapid growth and considerable sporulation may have led to the erroneous identification of this fungus as the cause of tea white scab disease. Our findings may be useful for future investigations of this disease, particularly regarding the development of improved prevention and/or control measures.