Abstract: In order to identify the disease caused by Phytophthora tentaculata, and keep the spread of the disease under control and reduce the economic losses quickly and accurately, loop-mediated isothermal amplification(LAMP)assay targeting the PtYpt1 element was used to detect Phytophthora tentaculata. The PtYpt1-LAMP assay amplified the target element in less than 80 min at 64 ℃ efficiently and was evaluated specificitily and sensitivitily. The specificity was evaluated against Phytophthora tentaculata, Phytophthora spp., Pythium spp., and true fungi isolates. The P. tentaculata DNA products were visualised as a ladder-like banding pattern by 2% gel electrophoresis. A positive colour(sky blue)was only observed in the presence of P. tentaculata by addition of hydroxynaphthol blue prior to amplification, whereas none of other isolates showed a colour change. The detection limit of the PtYpt1-specific LAMP assay for P. tentaculata was 1 ng/μL of genomic DNA per reaction.