DNA barcoding of pear psyllids (Hemiptera: Psylloidea: Psyllidae), a tale of continued misidentifications

Abstract

<jats:title>Abstract</jats:title><jats:p>Pear psyllids (Hemiptera: Psylloidea: Psyllidae: <jats:italic>Cacopsylla</jats:italic> spp.) belong to the most serious pests of pear (<jats:italic>Pyrus</jats:italic> spp.). They damage pear trees by excessive removal of phloem sap, by soiling the fruits with honeydew which, in turn, provides a substrate for sooty mould, and by transmission of <jats:italic>Candidatus</jats:italic> Phytoplasma spp., the causal agents of the pear decline disease. The morphological similarity, the presence of seasonal dimorphism that affects adult colour, size and wing morphology and uncritical use of species names, led to much confusion in the taxonomy of pear psyllids. As a result, pear psyllids have been frequently misidentified. Many of the entries attributed to <jats:italic>Cacopsylla pyricola</jats:italic> and other species in the GenBank are misidentifications which led to additional, unnecessary confusion. Here we analysed DNA barcodes of 11 pear psyllid species from eastern Asia, Europe and Iran using four mitochondrial gene fragments (COI 658 bp, COI 403 bp, COI-tRNA<jats:sup>leu</jats:sup>-COII 580 bp and 16S rDNA 452 bp). 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 of <jats:italic>Cacopsylla jukyungi</jats:italic> ( = <jats:italic>C. cinereosignata</jats:italic>, winter form) and <jats:italic>C. maculatili</jats:italic> ( = <jats:italic>C. qiuzili</jats:italic>, summer form) previously suggested based on morphology. Some previous misidentifications (<jats:italic>C. chinensis</jats:italic> from China, Japan and Korea = misidentification of <jats:italic>C. jukyungi</jats:italic>; <jats:italic>C. pyricola</jats:italic> and <jats:italic>C. pyrisuga</jats:italic> from East Asia = misidentification of <jats:italic>C. jukyungi</jats:italic> and <jats:italic>C. burckhardti</jats:italic>, respectively; <jats:italic>C. pyricola</jats:italic> from Iran = misidentification of <jats:italic>C. bidens</jats:italic>, <jats:italic>C. pyri</jats:italic> and <jats:italic>Cacopsylla</jats:italic> sp.) are also corrected. There is no evidence for the presence of European pear psyllid species in East Asia.</jats:p>

Differences in Gall Induction of Flower-like Galls on Haloxylon by Psyllids (Hemiptera: Aphalaridae), and the Emergence of Corresponding Parasitoids

“…and slight morphological differences among three species of Psyllaephagus spp., it was difficult to identify the species only by morphological characters. As such, determining their species identities using genetic analyses was identified as one of the priorities within a study with broader sampling [51,52]. As a routine procedure, all species reared from different galls were accurately identified by the combination of both molecular and morphological characters.…”

Anomoneura taiwanica sp. nov. (Hemiptera, Psylloidea, Psyllidae), a new jumping plant-louse species from Taiwan associated with Morus australis (Moraceae)

“…Morphological terminology follows mostly Ossiannilsson (1992), Hollis (2004), and Yang et al (2009). For molecular diagnosis, the COI-tRNA leu -COII fragment of mitochondrial DNA was used, as it is usually effective for comparison of closely related psyllid species (Cho et al 2020). Protocols for DNA extraction, amplification, sequencing, sequence alignment, and phylogenetic analysis were followed from Cho et al (2020).…”

“…For molecular diagnosis, the COI-tRNA leu -COII fragment of mitochondrial DNA was used, as it is usually effective for comparison of closely related psyllid species (Cho et al 2020). Protocols for DNA extraction, amplification, sequencing, sequence alignment, and phylogenetic analysis were followed from Cho et al (2020). In addition to the material of Anomoneura, two Acizzia species (Psyllidae, Acizziinae) were included in the phylogenetic analysis as outgroups (Table 1).…”

Synthesis of the enantiomers of 13‐methylheptacosane, the sex pheromone of pear psylla, Cacopsylla pyricola

“…Pear psylla (Cacopsylla pyricola) is a serious pest of pears, which has caused significant economic damage in North America and Europe. 1,2 Current control of this pest relies mainly on insecticides. 3 However, the increasing resistance to many insecticides, such as pyrethroid 4,5 and orgno-phosphorous, 6,7 has made the control more difficult.…”