Objective  To isolate and identify the pathogen causing cyst nematode infection in Yuexi, Sichuan.

  Method  Roots of the diseased potato plants as well as soil around them were collected to find nematodes by staining and examining under a microscope, while cysts separated by means of simple floatation. The second stage juveniles (J2s), female adults, and cysts found were photographed, and their morphological measurements recorded. DNA of the cysts and the J2s were extracted and identified by species-specific PCR. DNA sequences of 18S gene and 28s D2~D3 region, as well as the ITS location in ribosomal DNA, were obtained. Sequences of some cyst nematode species were downloaded from GenBank for alignment. MrBayes 3.2.3 software was used to construct the Bayesian phylogenetic tree.

  Result  The isolated nematode could infect the host root system. The J2 stylet knobs rounded to flattened anteriorly; the mean stylet length was less than 23 μm; and the cyst Granek’s ratio was higher or equal to 3, which is similar to that for Globodera rostochiensis. The DNA templates of 3 cysts and 4 J2s were amplified by species-specific PCR to obtain a band of approximately 430 bp. Further sequencing determined the length to be precisely 434 bp, same as G. rostochiensis. The cyst nematode was shown to be a species of Globodera by an evolutionary analysis on the rDNA 18S and 28S and confirmed to be G. rostochiensis by another evolutionary analysis on ITS gene.

  Conclusion  The isolated nematodes from Yuexi, Sichuan was identified as G. rostochiensis, which is of great concern for the domestic disease control and import quarantine, as it can be highly difficult to eradicate once being introduced and colonized in the country. Consequently, a stringent monitoring system must be implemented as soon as possible. Reinforced quarantine, supervision, and management to curtail the possible invasion are urgently needed. Increased efforts on the basic studies as well as developments of detection methodology and prevention and control technology on G. rostochiensis are recommended.