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.

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

The jumping plant-lice of Laos are reviewed based on material collected during recent expeditions by the Seoul National University (2012−2015) and the Naturhistorisches Museum Basel (2003−2012). To date, only three psyllid species, viz. Diaphorina citri, Heteropsylla cubana and Pseudophacopteron tuberculatum, are recorded from Laos. In the material at hand, 22 species (of 6 families and 16 genera) are represented. This collection includes the three previously reported species and eight species reported for the first time from Laos. Eleven species are identified only to genus due to insufficient material.

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.

Psyllids have shifted lately into general awareness as vectors of pathogens causing serious plant diseases, as pests in agriculture and forestry or as potential control agents of alien invasive weeds. These small insects are plant sap feeders which are generally very host specific. In addition, related psyllid species tend to develop on related plant species. This makes them an ideal group for studies on insect–plant cospeciation. A sound taxonomic and phylogenetic base is a prerequisite for successful pest control and meaningful research on insect–plant interactions. Currently almost 4000 named species of Psylloidea exist worldwide of which half was described in the last three decades. Despite this tremendous progress there are at least another 4000 species which remain undescribed particularly in Africa, South America and tropical Asia. Since White and Hodkinson’s seminal paper in 1985 a series of studies tested their classification with additional taxa using morphological and molecular techniques. In 2012 Burckhardt and Ouvrard proposed a new classification. Five of their families (Calophyidae, Carsidaridae, Homotomidae, Phacopteronidae and Triozidae) are identical with or similar to those of White and Hodkinson but three differ fundamentally from previous classifications (Aphalaridae, Liviidae and Psyllidae). Many of the recognised families and subfamilies are restricted more or less exclusively to a single plant taxon, e.g. Calophyidae, Phacopteronidae and Rhinocolinae to Sapindales, Carsidaridae to Malvaceae, Homotomidae to Moraceae, Spondyliaspidinae to Myrtaceae, and many Psyllidae to Fabaceae. The 1000 described species of Triozidae, in contrast, have colonised many families of dicots and, a few, even monocots and conifers. Several analyses suggest that cospeciation may be less important than geographical vicariance to explain the observed species richness in psyllids, and that shifts to new host taxa are frequent.