Tar spot of Dalbergia odorifera, caused by Phyllachora dalbergiicola, is a common disease, and se-riously affected the rate of photosynthesis. Here we developed a species-specific Nested-PCR approach for rapidand accurate detection of P. dalbergiicola, based on the differences in internal transcribed spacer （ITS） se-quences of P. dalbergiicola and another P. spp., an endophytic fungus, from which a pair of species-specificprimers P1/P2 （P1 ： 5＂-CGAGGTCAGAATCAAACG-3＂, P2： 5＂-TGAAGAACGCAGCGAAAT-3＂）, was designed.P1/P2 amplified only a unique 273 bp band from the genomic DNA of P. dalbergiicola. A Nested-PCR proce-dure using ITS4/ITS5 as the first-round primers, followed by P1/P2 primers, increased detection sensitivity10 000 fold to 100 ag. Using the Fast DNA-kit to extract DNA from the diseased plant tissues, the detection ofthe pathogen by Nested-PCR assay could be completed within I day. The results suggested that the PCR-basedmethods here could simplify both plant disease diagnosis and pathogen detection.
