Phytoplasmas are obligatory intracellular bacteria that colonize the phloem of many plant species and cause hundreds of plant diseases worldwide. In nature, phytoplasmas are primarily transmitted by hemipteran vectors. While all phloem‐feeding insects could in principle transmit phytoplasmas, only a limited number of species have been confirmed as vectors. Knowledge about factors that might determine the vector capacity is currently scarce. Here, we characterized the microbiomes of vector and non‐vector species of apple proliferation (AP) phytoplasma ‘Candidatus Phytoplasma mali’ to investigate their potential role in the vector capacity of the host. We performed high‐throughput 16S rRNA metabarcoding of the two principal AP‐vectors Cacopsylla picta and Cacopsylla melanoneura and eight Cacopsylla species, which are not AP‐vectors but co‐occur in apple orchards. The microbiomes of all species are dominated by Carsonella, the primary endosymbiont of psyllids and a second uncharacterized Enterobacteriaceae endosymbiont. Each Cacopsylla species harboured a species‐specific phylotype of both symbionts. Moreover, we investigated differences between the microbiomes of AP‐vector versus non‐vector species and identified the predominant endosymbionts but also Wolbachia and several minor taxa as potential indicator species. Our study highlights the importance of considering the microbiome in future investigations of potential factors influencing host vector competence. We investigated the potential role of symbiotic bacteria in the acquisition and transmission of phytoplasma. By comparing the two main psyillid vector species of Apple proliferation (AP) phytoplasma and eight co‐occurring species, which are not able to vector AP‐phytoplasma, we found differences in the microbial communities of AP‐vector and non‐vector species, which appear to be driven by the predominant symbionts in both vector species and Wolbachia and several minor taxa in the non‐vector species. In contrast, infection with AP‐phytoplasma did not affect microbiome composition in both vector species. Our study provides new insights into the endosymbiont diversity of Cacopsylla spp. and highlights the importance of considering the microbiome when investigating potential factors influencing host vector competence.

Apple proliferation is an economically important disease and a threat for commercial apple cultivation. The causative pathogen, the bacterium ‘Candidatus Phytoplasma mali’, is mainly transmitted by Cacopsylla picta, a phloem-feeding insect that develops on the apple tree (Malus spp.). To investigate the feeding behavior of adults of the phytoplasma vector Cacopsylla picta in more detail, we used deep sequencing technology to identify plant-specific DNA ingested by the insect. Adult psyllids were collected in different apple orchards in the Trentino-South Tyrol region of northern Italy. DNA from the whole body of the insect was extracted and analyzed for the presence of plant DNA by performing PCR with two plant-specific primers that target the chloroplast regions trnH-psbA and rbcLa. DNA from 23 plant genera (trnH) and four plant families (rbcLa) of woody and herbaceous plant taxa was detected. Up to six and three plant genera and families, respectively, could be determined in single specimens. The results of this study contribute to a better understanding of the feeding behavior of adult Cacopsylla picta.

Aim: Lymph node (LN) metastases are associated with poor outcomes in patients with recurrent larynx squamous cell carcinoma (LSCC). Neck dissection (ND) is therefore commonly performed along with salvage total laryngectomy (STL). Here, we assess the rate of occult LN metastases and the diagnostic value of MRI and PET/CT for detecting them in recurrent LSCC. Methods: This retrospective study included patients with recurrent LSCC after primary (chemo)radiotherapy [(C)RT] who were re-staged by MRI and/or PET/CT and treated with STL and ND between 2004 and 2019. The histopathology of ND samples was used as the reference standard. Results: Forty-one patients were included. The prevalence of occult metastases in MRI-negative and PET/CT-negative neck nodes was between 3.2% and 6.1%. Negative predictive values of neck node re-staging were 93.9% for MRI, 96.8% for PET/CT, and 96.2% for MRI and PET/CT combined. Conclusion: Both MRI and PET/CT afforded good negative predictive values for nodal staging in patients with recurrent LSCC after (C)RT prior to STL. In selected patients, these radiological modalities, particularly PET/CT, could help to avoid unnecessary surgery to the neck and its associated morbidity.