Tylenchulus semipenetrans is the most economically important and widespread nematode pest of citrus in China.rDNA-ITS of 14 populations of T.semipenetrans which were collected from different citrus groves or Chinese fir（Cunninghamia lanceolata） plantations in China were amplified and sequenced.The species-specific primers were designed for the first time to diagnosis T.semipenetrans based on the sequences of rDNA-ITS regions of geographic population above.The primers were sensitive to amplify the expected band size（297 bp） from DNA template of a single second-stage juvenile（J2） or different life stages of T.semipenetrans.No specific band was amplified from 15 non-target nematode species which were commonly found in citrus groves.Specificity and reliability of the primers were validated by further PCR amplification of 16 extra populations of T.semipenetrans collected from 4 provinces of China.The primers successfully detected a single J2 of T.semipenetrans within a whole nematode community comprising a large numbers of non-target nematode.The developed diagnostic technique can be used for accurate identification of T.semipenetrans and also as a decision tool for nematode management for citrus or Chinese fir in China.
LIU Guo-kunCHEN JuanXIAO ShunZHANG Shao-shengPAN Dong-ming
