Morphological and molecular characterization of the Colomerus vitis erineum strain (Trombidiformes: Eriophyidae) from grapevine erinea and buds

Grapevine Pinot gris virus spreads in infected vineyards: latent infections have no direct impact on grape production

BACKGROUND

Grapevine Pinot gris virus (GPGV) infects grapevines worldwide and causes symptoms such as chlorotic mottling and deformations on leaves, stunted shoots and short panicles, or none of these symptoms if it appears as latent infection. So far, the consequences of GPGV infections for winegrowers are difficult to assess since important information such as plant performance at different GPGV infection levels and symptom expression are not fully clarified.

METHODS

In order to investigate the course of GPGV spread, annual visual evaluations and ELISA tests were conducted over 3-4 consecutive years in four GPGV-infected vineyards in southern Germany: GEM, HEC, NIM, and REI. The program PATCHY was used to analyze spatial disease patterns. Sanger sequencing was used to determine virus isolates in vines at different GPGV infection levels, to test their respective influence on symptom expression. Yield and GrapeScan (FTIR) analyses were conducted to test the impact of different GPGV infection levels and isolates on fruit quantity and quality.

RESULTS

GPGV infections significantly increased in all four vineyards (GEM 22-32%, HEC 50-99%, NIM 83-90%, REI 56-76%) with significant spreading patterns across and along rows. Specific symptom progression patterns were not observed. According to our results, the virus isolate has an influence on whether symptoms develop during a GPGV infection. While yield analyses revealed that yield losses only occur in symptomatic vines and range from 13 to 96% depending on the severity of symptoms, latent infections have no impact on grape production. No relevant effects of GPGV infections on must quality were observed.

CONCLUSIONS

Secondary spread of GPGV was observed in all vineyards monitored, indicating vector-borne transmission that is likely to be accelerated by human viticultural management. GPGV should be further monitored to prevent the accumulation of detrimental symptomatic isolates. The results of this study can be used to assess the risk of GPGV to viticulture and should be considered when developing management strategies against the virus.

Geometric Morphometric Analysis and Molecular Identification of Coconut Mite, Aceria guerreronis Keifer (Acari: Eriophyidae) Collected from Thailand

One of the most impactful pests in several coconut production regions across the world is the coconut mite, Aceria guerreronis Keifer. Scholars can obtain some necessary biogeographic information about coconut mites from studies that explore the geographic patterns of morphological variations and molecular properties among coconut mite populations from various locales. To investigate the geographical origin, ancestral host associations, and colonization history of the mite in Thailand, we obtained DNA sequence data from two mitochondrial (16s and COI) and one nuclear region (ITS) from coconut mite samples originating from 25 populations; additionally, we analyzed the morphological variations in the prodorsal shield and the coxigenital and ventral regions of the mite idiosoma. From the results of experiments using both identification methods, we identified the mite as the coconut mite, A. guerreronis (Acari: Eriophyidae). According to the phylogenetic analysis results of the 25 mite samples, we classified the mites as being closely related to mites found by the authors of a previous report in India. We are the first to report the results of a geometric morphometric analysis and molecular identification of A. guerreronis in Thailand, and our findings support the idea that the mites' origin and invasion history are not well documented, which makes it difficult to apply quarantine procedures and search for biological pest control agents.

Integrative Taxonomy and Synonymization of Aculus mosoniensis (Acari: Eriophyidae), a Potential Biological Control Agent for Tree of Heaven (Ailanthus altissima)

Simple Summary

Tree of heaven, Ailanthus altissima, is a deciduous tree indigenous to China and introduced for ornamental purposes into North America and Europe. It shows a highly invasive profile in field, urban, and suburban areas, posing a serious threat to ecosystems in the introduced ranges. The current management of this noxious infesting plant by mechanical and chemical measures remains ephemeral and incomplete. A multi-tactic approach emphasizing classical biological control appears highly relevant. Eriophyid mites are well known for their high specificity and for the impact caused to the associated hosts, resulting in relevant potential biological control agents of infesting plants. The partially unresolved taxonomy of the eriophyid mite species reported on the tree of heaven is currently seen as an impediment to their further concern as biocontrol agents. This paper investigated morphological and molecular characters of Aculus mosoniensis in order to better clarify its taxonomic status. A paratype specimen of Aculops taihangensis was also studied, and this mite species was reassigned to the genus Aculus. The strong congruence between morphological and molecular analyses for all mites collected on tree of heaven in Europe led to the conclusion that A. mosoniensis is a junior synonym of Ac. taihangensis.

Abstract

The taxonomy of Aculus mosoniensis appears to be an unresolved question and its clarification is required, owing to the potential relevance of this mite species as a biological control agent of the tree of heaven. This paper is aimed at giving accurate details on a previously and shortly announced synonymization with Aculops taihangensis, using a morphological and molecular approach. A fusiform morph of A. mosoniensis was distinguished from a vermiform morph and this latter was recognized as deutogyne, which was herein documented. Phylogenetic relationships between Chinese Ac. taihangensis and all A. mosoniensis mites collected in twenty localities in Europe were examined through the analysis of the mitochondrial cytochrome c subunit I (CO1) protein and the nuclear ribosomal internal transcribed spacer 1 region (ITS1). CO1 sequences of Ac. taihangensis from the Shandong province in China and those from mites collected in Austria and Slovenia were 100% identical; the ITS1 sequence of an Ac. taihangensis paratype matched for 99.8% with those obtained from protogynes and deutogynes of A. mosoniensis collected in Italy. All these data supported the announced synonymization of A. mosoniensis with Ac. taihangensis. Aculusmosoniensis was found genetically variable, with five CO1 haplotypes in Europe (becoming eight along with those of Ac. taihangensis) clustering in two highly supported maternal lineages and eight ITS1 haplotypes (becoming nine along with those of Ac. taihangensis) distributed in four supported clades. No overlap between intra- and interspecies distances was observed for both markers and all studied A. mosoniensis populations clustered in one monophyletic mitochondrial clade, suggesting that only one single species might occur in Europe. However, more mite clades may be related to more tree of heaven biotypes with potential ecological differences, which might have potential effects on the biological control and should be investigated.

Molecular phylogeny of Phyllocoptes associated with roses discloses the presence of a new species

There are few plant maladies as devastating as rose rosette, a disease caused by an eriophyoid -transmitted virus. Rosette annihilates roses across North America, and to date, there is a single verified vector of the virus, Phyllocoptes fructiphilus Keifer. In direct contrast to the importance of rose for the ornamental industry there is limited knowledge on the eriophyoids that inhabit roses in North America and even less information on their vectoring capacities. This study dissects the genetic diversity of the eriophyoid fauna in rosette-affected hotspots and provides evidence of the existence of an undescribed species named Phyllocoptes arcani sp. nov., that could potentially be a second vector of the rosette virus.

Eriophyoid mites (Acari: Prostigmata) from Brazil: an annotated checklist

The superfamily Eriophyoidea constitute a group of phytophagous mites of particular economic and evolutionary interest due to their intimate association with host plants and their agricultural importance as harmful or beneficial organisms. Studies on the Eriophyoidea fauna in Brazil started in the early 1900s with botanical works on cecidias and were continued with researchers looking for and reporting on eriophyid mites causing damage to agricultural crops. Therefore, in this annotated checklist, we compile information from just over a century on eriophyid mites reported or described from Brazil. Its purpose is to facilitate plant protection strategies and guide future work on this important group of phytophagous mites. In addition to taxonomy, we present information on host plants and general aspects of cecidia attributed to eriophyoid mites but without genus/species identification. Compilation was based on: i) literature, including papers, books, theses and congress/symposium publications; ii) specimens deposited in mite collections in Brazil. On each species we present: i) suprageneric/generic classification, synonyms and previous genus/era assignments, including references on original and/or additional descriptions; ii) type host plant and other host(s) plant(s) found in the country; iii) host relationships and remarks on symptoms; iv) localities of occurrences at States/Federal District and municipal levels; and v) host plant status in Brazil as well as biomes where they occur or are cultivated. A total of 234 valid eriophyoid mite species are recorded: 196 Eriophyidae, 20 Diptilomiopidae and 18 Phytoptidae, distributed in 92 genera. Host plants comprised 233 species, belonging to 141 genera and 56 plant families. Four new reports of eriophyoid mites in Brazil are presented based on specimens deposited in reference collections. A new combination is presented for Propeaciota secundum (Flechtmann, Amrine Stasny) in the genus Khanthongella. In addition, data on observations and descriptions of 67 cecidias attributed to eriophyoid mites in five states and on 21 plant families are presented. Geographically, the distribution of species reports of eriophyoids around Brazil is highly uneven, with more than 64% of species (151 spp.) in the Southeast region, which surely reflects a lack of research elsewhere. Regarding host plant specificity, 77.7% are reported on only one host species, 88.9% on one host genus and 98.3% on one host family. Regarding host status 64.1% of species are exclusively associated with native host plants, 27% with naturalized or exotic cultivated host plants, and 6.4% from both native and naturalized or exotic host plants.

Molecular and phenotypic variations in Eutetranychus orientalis (Klein) populations from Saudi Arabia

The oriental red spider mite, Eutetranychus orientalis (Klein) is a major pest of citrus in many countries including Saudi Arabia (SA). The morphological variations among the different populations of E. orientalis were reported. In the present study, phenotypic variations based on 40 different morphological characteristics were evaluated in 10 E. orientalis populations collected from different hosts and regions of SA. Further, ITS2-rDNA sequences were used to confirm the identity of these phenotypically varying populations. Phenotypic variations in all populations were found in the shape and length of dorsal setae, striation pattern between setae d1 and e1, and leg chaetotaxy. The rDNA sequence analysis of these morphologically varying populations resulted in 10 different ITS2 Saudi haplotypes. The phenotypic and genetic variations were more related to the host plants rather than their geographic distribution. The E. orientalis population collected from Phoenix dactylifera was phenotypically distinct and genetically divergent. The populations collected from citrus species were also more phenotypically and genetically related to each other than to populations collected from non-citrus host plants. The haplotypes recovered from Ziziphus sp., Morus sp., and Azadirecta indica from different regions were grouped in the same sub-clade. Further, the ITS2 haplotypes of Saudi E. orientalis recovered from Citrus reticulata from Riyadh and Al Ula were 100% identical to the ITS2 haplotypes recovered from Citrus sp. from Israel. It is concluded that phenotypic variations exist among different populations of E. orientalis inhabiting different host plants. This species should be identified carefully by considering phenotypic intraspecific variations.