Anthracnose in US Tea: Pathogen Characterization and Susceptibility Among Six Tea Accessions

Tea (Camellia sinensis [L.] O. Kuntze) is under investigation as a specialty crop in the United States. Anthracnose is a serious disease in global tea production, but there is no literature on the susceptibility of U.S. planting materials to this disease. We isolated a Colletotrichum species from symptomatic plants in a field trial and identified the pathogen as Colletotrichum camelliae based on morphology and sequencing of the ITS, GS, GAPDH, TUB2, and ApMat domains. A phylogenetic analysis showed that local field isolates were genetically similar to one another and grouped with isolates from C. sinensis in China, whereas a local isolate from an ornamental camellia (C. japonica) was more closely related to C. camelliae isolated from other Camellia spp. Six commercially available tea accessions were evaluated in detached leaf assays for susceptibility to this anthracnose pathogen. All accessions were susceptible to infection, with Fairhope and Small Leaf having the largest lesion sizes. In field observations, Fairhope, Big Leaf, and Small Leaf consistently had lower disease severity than Georgian over two growing seasons. This work documents the impact of anthracnose on U.S. tea varieties and may help shape future directions of tea research, breeding, and recommendations for growers in establishing a novel industry.