First report of potato gangrene caused by Phoma foveata in China.
A potato tuber rot disease of unknown cause, affecting 5-15% of the potato tuber, was observed in Gansu, China, in March 2010. Sunken, round, oval, or irregular lesions formed at the umbilicus or buds of potato tubers after 30 days of storage at 4°C. These lesions gradually expanded to form khaki, lavender sunken lesions ranging from 1.0 to 3.0 cm. Small black bodies were observed in the centre of the lesions after 45 days. Pycnidia were black brown, spherical or oblate, scattered or clustered, and 82-210 × 64-175 µm in size. Conidia were unicellular, colourless, and 2.1-4.4 × 5.8-11.5 µm in size. Chlamydospores were spherical and 27-81 × 18-63 µm in size. The morphological characteristics of the isolate were similar to those of P. foveata [Boeremia foveata]. The nucleotide sequence of the 539-bp amplicon (GenBank accession no. JQ804843) was 99% identical to the ITS sequence from P. foveata available in the GenBank (GU237742). This is thought to be the first report of potato gangrene caused by P. foveata in China.