Ditylenchus arachis is a new species infecting peanut in China.It is difficult to distinguish between D.arachis and D.destructor based on morphology.To improve diagnostic accuracy, a molecular detection method was developed.The rDNA-ITS region for four isolates of D.arachis and three isolates of D.destructor were amplified using the universal primes and sequenced.Three amplification products were produced, a 1 031 bp amplicon for all isolates of D.arachis, a 943bp amplicon for two isolates of D.destructor and a 1 130bp amplicon for one isolate of D.destructor.Two pairs of specific primers were designed based on differences in these ITS sequences.One pair of specific primers (DF1/DR1) amplified a 170bp fragment and the other pair (DF2/DR2) amplified a 613bp fragment.The technology can be effectively used to detect D.arachis.