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Flavescence dorée (FD) is a European quarantine disease of grapevine caused by FD phytoplasma (FDp) transmitted by the leafhopper of North American origin Scaphoideus titanus. The disease affects the most important viticultural regions of Europe and all wine-growing regions of Serbia. Unlike the insect vector, the pathogen is native to Europe and associated with several wild host plants among which alder trees as the main source of two out of three map genetic clusters of pathogen variants (Map-FD1 and FD2). Heretofore, the FDp epidemic in Serbian vineyards was thought to be monotypic, i.e., caused by the single genotype of the Map-FD3 cluster, M51, and correlated with clematis as the natural source plant. This study aimed to provide data on genetic diversity, through map and vmpA gene typing, and insights into ecological properties of epidemiological cycles driving the epidemic outbreaks of FD in Serbia today. Map genotyping of 270 grapevine isolates collected from 2017 to 2019 confirmed M51 as autochthonous genotype widespread in all wine producing regions of Serbia and the dominant FDp epidemic genotype in most of the districts (75%, 202/270 isolates), except in north Serbia where multiple outbreaks of M12 Map-FD3 were recorded (54 isolates). Tree of heaven is reported as a new FDp plant reservoir for the Serbian vineyards, hosting the M51 genotype, along with clematis. An outbreak of a new endemic Map-FD3 genotype M144 was documented in grapevine samples from east Serbia (5 isolates), correlating with previous findings of the same genotype in clematis. In addition, single grapevine infections with five new Map-FD3 genotypes (M150-M154) were recorded in central Serbia, thus indicating high endemic potential for new outbreaks. The vmpA typing placed all Map-FD3 isolates into the VmpA-III cluster, i.e., Vectotype III. Finally, we found direct evidence that at least two FDp endemic genotypes, M89 and M148, of the Map-FD2/VmpA-II have escaped from alders and propagated in the grapevine-S. titanus pathosystem in Serbia (Vectotype II). Our findings confirm the high complexity of the FDp ecological cycle and provide evidence of a unique, autochthonous Balkan epidemiology sourced endemically.

The russet mite, Aceria anthocoptes (Nalepa), is the only eriophyoid that has been recorded on Cirsium arvense (L.) Scop. It has been noted in several European countries and recently in the USA. In this study we explored the geographic and host-related variability of Aceria spp. inhabiting different Cirsium spp. We applied landmark-based geometric morphometric methods to study morphological variability of three body regions (ventral, coxigenital and prodorsal) of 13 Aceria spp. populations inhabiting five Cirsium spp. in Serbia (Europe) and four Cirsium spp. in Colorado (North America). Analyses of size and shape variation revealed statistically significant differences between Aceria spp. living on European native and North American native Cirsium spp., as well as between A. anthocoptes s.s. inhabiting European C. arvense and North American C. arvense. The coxigenital region was the most informative when considering inter-population shape differences. European Aceria spp. dwelling on Cirsium spp., including A. anthocoptes s.s. from C. arvense, are characterized by higher inter-population size and shape variability than their North American counterparts. This finding supports a Eurasian origin of A. anthocoptes, presumed to consist of a complex of cryptic taxa probably coevolved with host plants in the native environment. Morphological similarity among Aceria spp. inhabiting North American native Cirsium spp. may indicate that speciation of A. anthocoptes started relatively soon after the host shift to plants different from C. arvense in the invaded region.

The eriophyoid mites are tiny but ancient and very diverse-over 5000 species have been named and described so far (Chetverikov et al. 2015;Bolton et al. 2017;Xue et al. 2017). They have received tremendous attention from acarologists over the last two decades or so. Major books-such as world catalogue (Amrine & Stasny 1994), key to genera (Amrine et al. 2003) and volumes of comprehensive review articles on its taxonomy, biology and control (Lindquist et al. 1996;Ueckermann 2010)-have facilitated the discovery and study of these mites in recent years. Surveys of new mite species described during 2007 to 2015 revealed that more new species of this superfamily have been described than any other mite superfamily (

Bois noir, an economically important disease of grapevine yellows that causes significant economic losses in wine production, is associated with ‘Candidatus Phytoplasma solani’ and transmitted to grapevines by cixiids Hyalesthes obsoletus and Reptalus panzeri. Polyphagous planthopper Dictyophara europaea, commonly found in natural habitats, harbors phytoplasmas from distinct groups and is an alternative vector in the open epidemiological cycles of the Flavescence dorée phytoplasma in grapevine in European vineyards. This study addresses the role of D. europaea in the transmission cycle(s) of ‘Ca. P. solani’ among wild habitats, natural reservoir plants, and the vineyard agroecosystem using MLSA and transmission trials with naturally infected adults to grapevine and Catharanthus roseus. The infection rates of D. europaea ranged from 7% to 13% in diverse locations, while reservoir herbaceous plants were infected in the amount of 29%. A total of 13 CaPsol MLSA genotypes were detected in D. europaea (7) and plants (8). Nine of them corresponded to previously identified genotypes. Two new genotypes were found in D. europaea (tuf-b1/S1/V14/Rqg50-sv1 and tuf-b1/S18/V14/Rqg50-sv1) and one in Convolvulus arvensis (tuf-b1/S1/V2-TA/Rqg31-sv1), whereas one was shared by two hosts, Crepis foetida and Daucus carota (tuf-b1/S1/V2-TA/STOL-sv1). Naturally infected D. europaea successfully transmitted the tuf-b1/S1/V2-TA/STOL type to five grapevines and six periwinkles, tuf-b1/S1/V2-TA/Rqg31 to one grapevine, and tuf-b1/S1/V2-TA/Rqg50 to one periwinkle, indicating that D. europaea is an intermediate vector in CaPsol epidemiological cycles.