scholarly journals Relationships between Hyalesthes obsoletus, Its Herbaceous Hosts and Bois Noir Epidemiology in Northern Italian Vineyards

Insects ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 606
Author(s):  
Nicola Mori ◽  
Elena Cargnus ◽  
Marta Martini ◽  
Francesco Pavan
Keyword(s):  
Host Plants ◽  
Control Strategies ◽  
Northern Italy ◽  
Adult Survival ◽  
Bois Noir ◽  
Potted Plants ◽  
Vector Population ◽  
Vector Abundance ◽  
The Relationship ◽  
Hyalesthes Obsoletus

Hyalesthes obsoletus is the vector of “Candidatus Phytoplasma (Ca. P.) solani,” the causal agent of grapevine yellows Bois noir (BN). The relationships among the planthopper, its main herbaceous hosts as phytoplasma reservoirs (Convolvolus arvensis and Urtica dioica) and BN spreading were studied in northern Italy. In two areas the relationship between host plants and the phenology and survival of planthopper adults was investigated in potted plants and in field conditions. Moreover, H. obsoletus ecology, newly symptomatic grapevine occurrence and “Ca. P. solani” tuf-types’ presence were studied in two vineyards (2014–2019). An earlier occurrence of H. obsoletus adults on C. arvensis than U. dioica and better adult survival of the originating host were observed. When U. dioica was prevalent, the vector occurred almost exclusively along the ditch outside the vineyard. Hyalesthes obsoletus amount varied widely from year to year and nymphal mortality due to late frosts was supposed. In one vineyard, the amount of newly symptomatic grapevines was significantly correlated with vector abundance in the previous year. The “Ca. P. solani” tuf-type was influenced by vector population levels on the two hosts. Since the abundance of H. obsoletus populations on the two hosts influences BN epidemiology and dynamics and the “Ca. P. solani” tuf-type, this must be considered in BN control strategies.

scholarly journals A genetic analysis reveals low prevalence of phytoplasma infection in Hyalesthes obsoletus Signoret, vector of 'bois noir', in SW-Germany

2015 ◽  
Author(s):  
Gabriele Schiro ◽  
Johannes Fahrentrapp ◽  
Florian Hartig ◽  
Bernd Panassiti
Keyword(s):  
Temporal Distribution ◽  
West Germany ◽  
Economic Losses ◽  
Type I ◽  
Wine Production ◽  
Bois Noir ◽  
Vector Population ◽  
Spatio Temporal ◽  
Low Prevalence ◽  
Hyalesthes Obsoletus

Bois Noir is a grapevine disease responsible for severe economic losses in wine production. Bois Noir is caused by Candidatus Phytoplasma solani, cell wall-less bacteria belonging to the taxonomic group 16Sr-XII-A. In Germany, they are known to be vectored from plant to plant by the cixiid Hyalesthes obsoletus, but so far the prevalence of the disease in the vector population, as well as its spatio-temporal distribution is poorly understood. We therefore analyzed infections of H. obsoletus collected in different vineyards in Baden (South-Western Germany) with quantitative real-time PCR. From 125 analyzed individuals, only five were infected with Ca. Phytoplasma solani. All infected individuals were colonized by Ca. Phytoplasma solani type I which is associated with the host plant Urtica dioica (stinging nettle). More research is needed to understand the reasons of this surprisingly low prevalence of Bois Noir in the population of H. obsoletus in South-West Germany.

scholarly journals Molecular Diversity of Phytoplasmas Associated with Grapevine Yellows Disease in North-Eastern Italy

2018 ◽  
Vol 108 (2) ◽  
pp. 206-214 ◽  
Author(s):  
Yuri Zambon ◽  
Alessandro Canel ◽  
Assunta Bertaccini ◽  
Nicoletta Contaldo
Keyword(s):  
Molecular Diversity ◽  
Direct Sequencing ◽  
Northern Italy ◽  
Bois Noir ◽  
Aster Yellows ◽  
Flavescence Dorée ◽  
Scaphoideus Titanus ◽  
North Eastern ◽  
Elm Yellows ◽  
Hyalesthes Obsoletus

A 3-year survey was conducted in Northern Italy to verify the presence and diversity of phytoplasmas in selected vineyards showing symptoms of severe yellows. Symptomatic and asymptomatic grapevines were sampled, and insects were collected using yellow sticky traps. The phytoplasmas detected in grapevine samples were different according to the years: “flavescence dorée” (16SrV-C/D) was detected together with other phytoplasmas such as 16SrXII-A (‘Candidatus Phytoplasma solani’-related, bois noir), 16SrI-B (‘Ca. P. asteris’-related, aster yellows), 16SrX-B (‘Ca. P. prunorum’-related, European stone fruit yellows), and 16SrV-A (‘Ca. P. ulmi’-related, elm yellows). Moreover, phytoplasmas belonging to 16SrVII-A (‘Ca. P. fraxini’-related) and 16SrVI (‘Ca. P. trifolii’-related) subgroups were also identified. Identification of phytoplasmas was also carried out from insects and showed the presence of some of these phytoplasmas in Scaphoideus titanus and Orientus ishidae: 16SrXII-A, 16SrVII, and 16SrVI phytoplasmas were detected in specimens of both species, while 16SrXII-A and 16SrI-B phytoplasma strains were identified in Orientus ishidae and Hyalesthes obsoletus, and 16SrX-B in S. titanus. Direct sequencing of selected amplicons obtained from 16S rRNA, rp, and tuf genes from grapevine and insect samples confirmed the phytoplasma identification. The 16SrVII-A and 16SrVI phytoplasmas were never detected before in grapevine, S. titanus and Orientus ishidae in Europe and their epidemiological importance is being monitored.

scholarly journals Entomopathogenic nematodes and fungi to control Hyalesthes obsoletus (Hemiptera: Auchenorrhyncha: Cixiidae)

BioControl ◽  
2021 ◽  
Author(s):  
Abdelhameed Moussa ◽  
Michael Maixner ◽  
Dietrich Stephan ◽  
Giacomo Santoiemma ◽  
Alessandro Passera ◽  
...  
Keyword(s):  
Life Cycle ◽  
Weed Management ◽  
Host Plants ◽  
Entomopathogenic Nematodes ◽  
Management Strategies ◽  
Biocontrol Agents ◽  
Herbicide Application ◽  
Isaria Fumosorosea ◽  
Bois Noir ◽  
Hyalesthes Obsoletus

AbstractHyalesthes obsoletus Signoret (Hemiptera: Auchenorrhyncha: Cixiidae) is a univoltine, polyphagous planthopper that completes its life cycle, including the subterranean nymph cryptic stage, on herbaceous weeds. In vineyards, it can transmit ‘Candidatus Phytoplasma solani’, an obligate parasitic bacterium associated with bois noir (BN) disease of grapevine, from its host plants to grapevine when occasionally feeding on the latter. The main disease management strategies are based on vector(s) control. Insecticide treatments on grapevine canopy are completely inefficient on H. obsoletus, due to its life cycle. Consequently, control of this planthopper focuses on the nymphs living on the roots of their host plants. Such practices, based on herbicide application and/or weed management, can reduce vector density in the vineyard but can impact the environment or may not be applicable, highlighting the necessity for alternative strategies. In this study, the efficacy of entomopathogenic nematodes (EPNs; Steinernema carpocapsae, S. feltiae, Heterorhabditis bacteriophora) and fungi (EPFs; Beauveria bassiana, Metarhizium anisopliae, Isaria fumosorosea, Lecanicillium muscarium) against H. obsoletus nymphs (EPNs) and adults (EPNs and EPFs) was assessed under laboratory and greenhouse conditions. The majority of examined EPNs and EPFs were able to kill H. obsoletus exhibiting a range of effectiveness. S. carpocapsae (among EPNs) and I. fumosorosea (among EPFs) were found to be the most effective biocontrol agents in all trials carried out. Advantages and limitations of such promising biocontrol agents were discussed. Ecological competency and conditions that can impede or enhance the EPNs and EPFs performance should be investigated to optimize their performance under field conditions.

Correlation of bois noir disease with nettle and vector abundance in northern Italy vineyards

2011 ◽  
Vol 85 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Nicola Mori ◽  
Francesco Pavan ◽  
Nazareno Reggiani ◽  
Mirko Bacchiavini ◽  
Luca Mazzon ◽  
...  
Keyword(s):  
Northern Italy ◽  
Bois Noir ◽  
Vector Abundance

Identification and phenology of Hyalesthes obsoletus (Hemiptera: Auchenorrhyncha: Cixiidae) nymphal instars

2012 ◽  
Vol 102 (5) ◽  
pp. 504-514 ◽  
Author(s):  
E. Cargnus ◽  
F. Pavan ◽  
N. Mori ◽  
M. Martini
Keyword(s):  
Host Plants ◽  
Morphological Characteristics ◽  
Flight Period ◽  
Correct Identification ◽  
Convolvulus Arvensis ◽  
Bois Noir ◽  
Morphological Studies ◽  
First Instar ◽  
Main Host ◽  
Hyalesthes Obsoletus

AbstractUrtica dioica and Convolvulus arvensis are the main host plants of Hyalesthes obsoletus and play an important role in the epidemiology of Bois noir of grapevines. The earliest survey, which was carried out to compare the phenology of nymphal instars on U. dioica and C. arvensis, had highlighted some problems in the identification of the instars. Therefore, the correct identification of nymphs to species and instar level became a preliminary aim of this research. Adults and nymphs attributable to H. obsoletus were collected during 2008–2010 in three flatland vineyard habitats of northern Italy on U. dioica, C. arvensis and Artemisia verlotorum. Nymphs and morphologically identified adults of H. obsoletus were submitted to molecular identification. Morphometric and morphological studies were carried out on nymphs collected in the field or obtained in laboratory rearings. Molecular methods not only confirmed the identity of adults, but also allowed the assignment of the nymphs to this species. Morphometric and morphological characteristics (e.g. body and head-thoracic lengths, number of thoracic pits) showed the existence of five nymphal instars. Morphometric differences between newly hatched and older first-instar nymphs were observed. A key to distinguish the five instars was proposed. Evident differences between H. obsoletus nymphs studied here and elsewhere were identified. According to differences in adult-flight period, an earlier phenology of nymphs on C. arvensis than on U. dioica was observed. In particular, the typical overwintering instar was the second on U. dioica and the third on C. arvensis.

scholarly journals A genetic analysis reveals low prevalence of phytoplasma infection in Hyalesthes obsoletus Signoret, vector of 'bois noir', in SW-Germany

2015 ◽  
Author(s):  
Gabriele Schiro ◽  
Johannes Fahrentrapp ◽  
Florian Hartig ◽  
Bernd Panassiti
Keyword(s):  
Temporal Distribution ◽  
West Germany ◽  
Economic Losses ◽  
Type I ◽  
Wine Production ◽  
Bois Noir ◽  
Vector Population ◽  
Spatio Temporal ◽  
Low Prevalence ◽  
Hyalesthes Obsoletus

Bois Noir is a grapevine disease responsible for severe economic losses in wine production. Bois Noir is caused by Candidatus Phytoplasma solani, cell wall-less bacteria belonging to the taxonomic group 16Sr-XII-A. In Germany, they are known to be vectored from plant to plant by the cixiid Hyalesthes obsoletus, but so far the prevalence of the disease in the vector population, as well as its spatio-temporal distribution is poorly understood. We therefore analyzed infections of H. obsoletus collected in different vineyards in Baden (South-Western Germany) with quantitative real-time PCR. From 125 analyzed individuals, only five were infected with Ca. Phytoplasma solani. All infected individuals were colonized by Ca. Phytoplasma solani type I which is associated with the host plant Urtica dioica (stinging nettle). More research is needed to understand the reasons of this surprisingly low prevalence of Bois Noir in the population of H. obsoletus in South-West Germany.

scholarly journals Proposal of A New Bois Noir Epidemiological Pattern Related to ‘Candidatus Phytoplasma Solani’ Strains Characterized by A Possible Moderate Virulence in Tuscany

Pathogens ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 268 ◽  
Author(s):  
Roberto Pierro ◽  
Alessandra Panattoni ◽  
Alessandro Passera ◽  
Alberto Materazzi ◽  
Andrea Luvisi ◽  
...  
Keyword(s):  
Host Plants ◽  
Molecular Detection ◽  
Relative Concentration ◽  
Statistical Analyses ◽  
Sequence Variant ◽  
Bois Noir ◽  
Epidemiological Pattern ◽  
Strain Type ◽  
Hyalesthes Obsoletus

Bois noir (BN), associated with ‘Candidatus Phytoplasma solani’ (CaPsol), is the most widespread disease of the grapevine yellows complex worldwide. In this work, BN epidemiology was investigated in a case study vineyard where an unusual CaPsol strain, previously detected only in other host plants, was found to be prevalent in grapevine. Experimental activities included: symptom observation; sampling of symptomatic vines, Auchenorrhyncha specimens, and weeds; molecular detection and typing of CaPsol strains; statistical analyses for determining possible relationships between CaPsol relative concentration, strain type, and symptom severity. Among insects, Reptalus quinquecostatus was the most abundant and was found to be highly infected by CaPsol, while Hyalesthes obsoletus, the main CaPsol vector, was not caught. Moreover, R. quinquecostatus harbored CaPsol strains carrying uniquely the stamp sequence variant St10, also identified as prevalent in vines and in the majority of weeds, and all the secY variants identified in the vineyard. Statistical analyses revealed that CaPsol strains carrying the St10 variant are not associated with severe symptoms, suggesting their possible moderate virulence. Based on such evidence, a new BN epidemiological pattern related to these CaPsol strains and involving grapevine, R. quinquecostatus, and/or weeds is proposed. Furthermore, the possible presence of other players (vectors and weeds) involved in CaPsol transmission to grapevines was highlighted.

scholarly journals A genetic analysis reveals low prevalence of phytoplasma infection in Hyalesthes obsoletus Signoret, vector of 'bois noir', in SW-Germany

2014 ◽  
Author(s):  
Gabriele Schiro ◽  
Johannes Fahrentrapp ◽  
Florian Hartig ◽  
Bernd Panassiti
Keyword(s):  
Temporal Distribution ◽  
West Germany ◽  
Economic Losses ◽  
Type I ◽  
Wine Production ◽  
Bois Noir ◽  
Vector Population ◽  
Spatio Temporal ◽  
Low Prevalence ◽  
Hyalesthes Obsoletus

Bois Noir is a grapevine disease responsible for severe economic losses in wine production. Bois Noir is caused by Candidatus Phytoplasma solani, cell wall-less bacteria belonging to the taxonomic group 16Sr-XII-A. In Germany, they are known to be vectored from plant to plant by the cixiid Hyalesthes obsoletus, but so far the prevalence of the disease in the vector population, as well as its spatio-temporal distribution is poorly understood. We therefore analyzed infections of H. obsoletus collected in different vineyards in Baden (South-Western Germany) with quantitative real-time PCR. From 125 analyzed individuals, only five were infected with Ca. Phytoplasma solani. All infected individuals were colonized by Ca. Phytoplasma solani type I which is associated with the host plant Urtica dioica (stinging nettle). More research is needed to understand the reasons of this surprisingly low prevalence of Bois Noir in the population of H. obsoletus in South-West Germany.

scholarly journals Temporal Dynamics of ‘Ca. Phytoplasma mali’ Load in the Insect Vector Cacopsylla melanoneura

Insects ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 592
Author(s):  
Valentina Candian ◽  
Monia Monti ◽  
Rosemarie Tedeschi
Keyword(s):  
Host Plants ◽  
Developmental Stages ◽  
Temporal Dynamics ◽  
Control Strategies ◽  
Vector Competence ◽  
Insect Vector ◽  
Life Stages ◽  
Candidatus Phytoplasma Mali ◽  
High Infection ◽  
Cacopsylla Melanoneura

The transmission of phytoplasmas is the result of an intricate interplay involving pathogens, insect vectors and host plants. Knowledge of the vector’s competence during its lifespan allows us to define more sustainable well-timed control strategies targeted towards the most worrisome life stages. We investigated the temporal dynamics of ‘Candidatus Phytoplasma mali’ load in Cacopsylla melanoneura in the different developmental stages in Northwest Italy. The phytoplasma load in the vector was evaluated in overwintering adults, nymphs and newly emerged adults after different acquisition access periods. Moreover, we followed the multiplication of the phytoplasma during the aestivation and the overwintering period on conifers. Our results confirmed the ability of remigrants to retain the phytoplasma until the end of winter. We also highlighted the high acquisition efficiency and vector competence, based on phytoplasma load, of nymphs and newly emerged adults. Therefore, particular attention should be paid to the management of overwintered C. melanoneura as soon as they return to the orchards, but also to newly emerged adults, particularly in orchards with a high infection rate and when the migration to conifers is delayed.

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