‘Candidatus Liberibacter solanacearum’ detected in Trioza urticae using suction trap-based monitoring of psyllids in Germany

Psyllids are small, phloem-feeding insects. Several species are vectors of economically important pathogens, such as ‘Candidatus Liberibacter solanacearum’ (CLso) and phytoplasmas. We monitored the psyllid population in Quedlinburg, Germany, using a 12.2-m suction trap from May to September 2017 in order to detect potential vectors for CLso, a pathogen of apiaceous and solanaceous crops. CLso has been previously detected in Germany in the carrot psyllid, Trioza apicalis. Psyllids were identified using a combination of morphological and molecular methods, and samples of each species were tested for CLso. No known vectors of CLso were captured. However, we detected CLso of unknown haplotype in a single individual of Trioza urticae, which mainly feeds on Urtica spp. A so-called haplotype U was recently described in Finland and was associated with Trioza urticae and Urtica dioica. This is the first report of CLso in T. urticae in Germany.