Flavescence dorée (FD) and Bois noir (BN) are the principal grapevine yellows in Europe caused by distinct phytoplasmas: BN by Candidatus Phytoplasma solani, FD by 16SrV-C and -D phytoplasmas (FDp) transmitted by the introduced Nearctic Deltocephalinae Scaphoideus titanus. FDp is listed as a quarantine pest in the European Union (Regulation (EU) 2019/2072). Black Alder (Alnus glutinosa) is a common asymptomatic host of 16SrV phytoplasmas in Europe and considered the original host of FDp (Malembic-Maher et al. 2020). Palatinate grapevine yellows (PGY) transmitted from alder to grapevine by the Macropsinae Oncopsis alni is not transmissible by S. titanus (Malembic-Maher et al. 2020). Germany is considered free from FD in grapevine and from its vector. A single case in a nursery in 2014 was eradicated (EPPO 2017), and FD was never before detected in a vineyard. Since S. titanus appeared in 2016 in the neighboring French Region of Alsace, monitoring of FD was carried out in Germany following a risk based strategy. It was focused on vineyard plots within a distance of 100 m from stands of alder. A geodata-based risk map (Jalke 2020) was used to localize those plots. All symptomatic vines sampled until September 2020 proved to be infected by BN or, occasionally, by PGY. Eight vines with typical symptoms were sampled in vineyards adjacent to alder stands in the winegrowing region of Rheinhessen in September 2020. Symptoms comprised leaf rolling and discoloration, incomplete lignification, and black pustules arranged in lines along the shoots. Diseased shoots were black and necrotic in December. Leaf midribs were sampled for total nucleic acids extraction. The phytoplasma 16S rRNA gene was amplified by generic primers R16F2/R2-mod followed by a nested PCR using 16Sr(V) group-specific primers R16(V)F1/R1, and primers R16(I)F1/R1 (Lee et al. 1995) to detect ‘Candidatus Phytoplasma solani’, associated with BN. While BN was detected in seven vines, one sample tested positive for 16SrV phytoplasma. This result was confirmed by triplex real-time Taq-Man assay based on rpl14 gene sequences (IPADLAB), by multiplex real-time PCR of map locus as well as by Loop-mediated isothermal amplification (LAMP) according to the EPPO diagnostic standard PM 7/079(2) (EPPO 2016). PCR-products of the map and the vmpA genes (Malembic-Maher et al. 2020) were sequenced and compared to reference sequences to distinguish between FD- and non-FD genotypes. The isolate from the diseased vine (GenBank MW 727272) exhibited 100% identity with map-M38 (GenBank LT221933), a genotype of the map-FD2 cluster. The same genotype was detected in A. glutinosa and Allygus spp. sampled at the infested site. A 234 bp sequence of the first repeat of the vmpA gene (GenBank MW727273) showed 100% identity with the homologous part of isolate FD-92 (GenBank LN680870) of the vmpA-II cluster. It can be concluded, that the symptomatic grapevine was infected by FD and not PGY This is the first report of FD in a productive vineyard in Germany. The infected vine of cv. Silvaner was 25 years old. While infected planting material is an unlikely source of the infection, a transmission of FDp from alder is highly probable. Finding a single FD-infection after several years of testing implies a low risk originating from the wild compartment, but the approach and possible establishment of S. titanus expected to be able to colonize the area (Jeger et al. 2016) justifies further monitoring activities. The infected vine was eradicated.

Xylem‐feeding is apparently the only requirement making an insect a competent vector of the bacterium Xylella fastidiosa, an organism responsible for the devastation of the Southern Italian olive forest and nowadays considered one of the most feared threats to agriculture and landscape in Europe, including vineyards. Here, we used the direct current‐electrical penetration graph (DC‐EPG) technique to compare and describe the feeding behaviour on grapevine of four xylem‐feeding species considered candidate vectors of X. fastidiosa widespread in Europe, namely two spittlebugs (the meadow spittlebug Philaenus spumarius and the spittlebug Neophilaenus campestris) and two sharpshooter leafhoppers (the rhododendron leafhopper Graphocephala fennahi and the green leafhopper Cicadella viridis). We created a standard for the analysis of EPG waveforms recorded with a DC‐EPG device, describing feeding activities performed by these insects from stylet insertion into the plant to withdrawal. This standard, along with freely available software, has been developed to harmonize the calculation of feeding behavioural parameters in xylem‐feeders. The most relevant differences between the two vector taxa were the probing frequency and the dynamics of xylem ingestion. Sharpshooters tended to perform significantly more probes than spittlebugs. In contrast, the latter spent longer times in low‐frequency xylem ingestion, characterized by scattered contractions of the cibarial dilator muscle interspersed with periods of pump inactivity. Cicadella viridis was the species displaying the highest frequency of the electrical pattern found to be associated with X. fastidiosa inoculation in spittlebugs (Xe). Feeding behavioural data presented here represent an important step forward for deepening our knowledge of xylem‐sap feeding insects' interaction with both the host plants and the bacterium they transmit.