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Tea-oil tree (Camellia oleifera Abel) is an important edible oil woody plant with a planting area over 3,800,000 hectares in southern China. Anthracnose is a serious disease of tea-oil tree in southern China, causing severe economic losses and posing a huge threat to the Ca. oleifera industry. Based on recent developments in the classification of Colletotrichum species, the objective of this study was to identify Colletotrichum species associated with tea-oil tree and examine their pathogenicity on leaves and fruits of Ca. oleifera. In total, 232 isolates were obtained from Ca. oleifera leaves and fruits with anthracnose symptoms. These isolates were further characterized based on morphology and multilocus phylogenetic analyses using partial DNA sequences at the ribosomal internal transcribed spacer regions and β-tubulin, actin, calmodulin, glyceraldehyde-3-phosphate dehydrogenase, and chitin synthase-encoding genes. The fungal isolates belong to five species: C. camelliae, C. fructicola, C. siamense, C. aenigma, and C. gloeosporioides. C. camelliae was the most predominant and widely distributed species on fruits of Ca. oleifera (91.4%), followed by C. fructicola (6.3%). However, C. fructicola was common and widely distributed species on leaves (75.9%), followed by C. camelliae (17.2%). There was no evidence of geographical specialization of the different species. Pathogenicity assays showed that all tested isolates, including 20 of C. camelliae, 11 of C. fructicola, four of C. siamense, two of C. aenigma, and one of C. gloeosporioides, were pathogenic to leaves and fruits of Ca. oleifera. Among the five species, C. camelliae species showed strong pathogenicity on both leaves and fruits of Ca. oleifera, and C. fructicola, C. siamense, C. aenigma, and C. gloeosporioides all showed weak pathogenicity on both leaves and fruits. No relationship was found between origin of isolates and their virulence. This is the first description of C. camelliae, C. fructicola, C. siamense, and C. gloeosporioides from the fruits of Ca. oleifera in China.

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The existing parametric formulae to calculate the notch stress concentration factor of fillet welds often result in reduced accuracy due to an oversimplification of the real weld geometry. The present work proposes a parametric formula for the evaluation of the notch SCF based on the spline weld model that offers a better approximation of the real shape of the fillet weld. The spline model was adopted in FE analyses on T-shape joints and cruciform joints models, under different loading conditions, to propose a parametric formula for the calculation of the SCF by regression analysis. In addition, the precision of parametric formulae based on the line model was examined. The magnitude of the stress concentration was also analyzed by means of its probability distribution. The results show that the line model is not accurate enough to calculate the SCF of fillet weld if the weld profile is considered. The error of the SCF by the proposed parametric formulae is proven to be smaller than 5% according to the testing data system. The stress concentration of cruciform joints under tensile stress represents the worst case scenario if assessed by the confidence interval of 95% survival probability.