Abstract: With Carposina coreana Kim as the out-group, using 44 random primers,the RAPD analysis was conducted on the host races of the peach fruit borer, Carposina sasakii Matsumura, from 6 different host plants, i.e., apple, hawthorn, peach, apricot, jujube and wild jujube, in Shaanxi Province. The results show that there exists great genetic differentiation between the host races. The genetic distances among the six host races of the peach fruit borer vary from 0.040 to 0.637, with the apricot race differs most markedly from other host races. Based on the clustering analysis, the six host races of the peach fruit borer from the various host plants can be divided into two sub-groups: the apricot race as a sub-group, and the others as another sub-group. The genetic distance is 0.465 between the two subgroups, and 0.040 to 0.369 within a sub-group. It is sugges ted that the apricot race of the peach fruit borer have been so differentiated genetically with the others that it should be considered as a good species.

Key words: Carposina sasakii, Carposina coreana, speciation, biotype, RAPD