Pear psyllids belong to the most serious pests of pear. They damage pear trees by excessive removal of phloem sap, by soiling the fruits with honeydew which, in turn, provides a substrate for sooty mold, and by transmission of Candidatus Phytoplasma, the causal agents of the pear decline disease. The morphological similarity, the presence of seasonal dimorphism that affect adult colour, size and wing characters, and uncritical use of species names, led much confusion in the taxonomy of pear psyllid species. As a result, pear psyllids have been frequently misidentified. Here we analysed DNA barcodes of eleven pear psyllid species from eastern Asia, Europe and Iran using four mitochondrial gene fragments. The efficiency of identification was notably high and considerable barcoding gaps were observed in all markers. Our results confirm the synonymies of the seasonal forms. Previous misidentifications are also corrected. There is no evidence for the presence of European pear psyllid species in East Asia.

Nomenclatural changes are provided for Sorbus-feeding Cacopsylla moiwasana (Kuwayama, 1908) species group. Thirteen Palaearctic Cacopsylla species have been recorded from Sorbus L. (Rosaceae), and of these, seven species restricted to East Asia. Among the East Asian species, four Japanese species, i.e. C. elegans Inoue, 2004, C. jezoensis (Miyatake, 1963), C. midoriae (Miyatake, 1963) and C. moiwasana (Kuwayama, 1908), assigned to C. moiwasana species group. Above the latter three species very similar to each other, allopatrically distributed, and all or some of them could be synonymous. The present investigation of the type material resulted in confirmation that Psylla jezoensis and P. midoriae should be treated as junior synonym of P. moiwasana. The following synonyms are proposed: Cacopsylla moiwasana (Kuwayama, 1908) = Psylla jezoensis Miyatake, 1963, syn. nov., Psylla midoriae Miyatake, 1963, syn. nov. The species are newly recorded from Korea.

The confused taxonomy of the east Palaearctic pear psyllids, serious pests on cultivated pear, is reviewed. Fifty-sixnominal species have been reported from Pyrus, 25 of which we consider valid and ten as not being associated withPyrus. Our taxonomic revision suggests that, in Korea, four Cacopsylla species develop on pear. Three species occuralso in Japan. New synonyms are suggested and seasonal dimorphism are critically discussed.Key words : Psyllidae, Cacopsylla, taxonomy, host plant, Pyrus, Rosaceae, Manchrian pear, Asian pear, European pear, China,Japan, South Korea, Russian Far East

Pear psyllids are of major economic concern in Korea. In the literature five nominal species, including two West Palaearctic taxa, are reported from the Peninsula. The Korean pear psyllids, member of the large genus Cacopsylla, are reviewed here to comprise four species. Previous Korean records of C. pyrisuga (Foerster) are misidentification of C. burckhardti Luo et al. whereas those of C. pyricola (Foerster) concern C. maculatili Li and probably C. jukyungi (Kwon) stat. rev., comb. nov. (from Psylla). The latter, that is commonly found in pear orchards, occurs also in Japan where it was misidentified as C. chinensis. The differences between C. jukyungi and C. cinereosignata syn. nov. reflect seasonal dimorphism. For this reason, we synonymise the two. C. maculatili and C. qiuzili Li are shown to represent the winter and the summer form of the same species and are, therefore, synonymised as C. maculatili = C. qiuzili syn. nov. C. jukyungi and C. sandolbaea (Park & Lee) are redescribed, a key to the adult of the four species and short biological notes are provided.