Characterization and pathogenicity of Colletotrichum camelliae causing brown blight disease of tea (Camellia sinensis) in Malaysia

Abstract

Tea (Camellia sinensis (L.) Kuntze) is a dicotyledonous woody shrub species widely cultivated to produce a beverage made from its leaves. Brown blight is a destructive foliar fungal disease that reduces tea production and degrades quality, resulting in lower market value. Typical brown blight symptoms observed in three commercial tea plantations in Malaysia were characterized as brownish to black lesions on young leaves. The lesions expanded with age, becoming darker and developing into necrotic cells. A total of 45 fungal isolates were isolated from brown blighted tea leaves and identified as Colletotrichum camelliae. Morphological characteristics coupled with universal spacer region and multigene phylogenetic relationships using the internal transcribed spacer (ITS), β-tubulin (tub2) and glyceraldehyde-3-phosphate dehydrogenase (gapdh) were used to accurately identify fungal isolates. The results of the pathogenicity test revealed that C. camelliae was responsible for causing brown blight disease of tea. This study highlights the occurrence of C. camelliae which causes tea brown blight in Malaysia. These findings may assist in disease monitoring, strict quarantine and effective control management of diseased tea plants.