Cacopsylla melanoneura Has No Relevance as Vector of Apple Proliferation in Germany

Long-term field surveys on the distribution and natural infection rates of Cacopsylla melanoneura were carried out in commercial and abandoned apple-proliferation-infected orchards throughout Germany, northern Switzerland, and eastern France. Although the infection rates of some orchards reached up to 80%, only 0.09% of all C. melanoneura collected on apple were infected by the pathogen ‘Candidatus Phytoplasma mali’. Despite higher population densities, no infected individual was found on wild hawthorn. Individuals of C. melanoneura were not able to transmit phytoplasmas to healthy plants, and even the acquisition of ‘Ca. P. mali’ from infected plants was very inefficient. Quantitative real-time polymerase chain reaction demonstrated that the very few infected individuals of C. melanoneura harbored phytoplasma concentrations 10,000 times lower than individuals of C. picta, the main vector species in Germany. Oviposition bioassays showed that hawthorn is the preferred reproduction host plant for C. melanoneura in Germany, not apple. Because hawthorn is not a suitable host plant for ‘Ca. P. mali’, it does not play a role in the spread of apple proliferation. In contrast to data reported from northwestern Italy, C. melanoneura developed on either apple or hawthorn has no relevance as a vector of apple proliferation in Germany. The existence of epidemiologically different populations is proposed.

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Characteristics of the Spread of Apple Proliferation by Its Vector Cacopsylla picta

Phytopathology ◽

10.1094/phyto-01-11-0012 ◽

2011 ◽

Vol 101 (12) ◽

pp. 1471-1480 ◽

Cited By ~ 11

Author(s):

Barbara Jarausch ◽

Nora Schwind ◽

Annette Fuchs ◽

Wolfgang Jarausch

Keyword(s):

Infection Rate ◽

Natural Infection ◽

Regional Scale ◽

Agricultural Practices ◽

Transmission Efficiency ◽

Apple Proliferation ◽

Female Ratio ◽

Northern Switzerland ◽

Cacopsylla Picta ◽

Candidatus Phytoplasma Mali

The distribution and natural phytoplasma infection of Cacopsylla picta were investigated during a long-term field survey between 2002 and 2009 in commercial and abandoned apple proliferation-infected orchards throughout Germany, northern Switzerland, and eastern France. Comparable population dynamics were described for the different sites whereas considerable variations in the absolute population densities were observed among the years. Individual polymerase chain reaction (PCR) testing revealed, for each year, a rather stable natural infection rate with ‘Candidatus Phytoplasma mali’ of ≈10% for overwintered adults of C. picta. Both genders were equally highly infected although more females were caught. The overall male/female ratio was 1:1.5. No direct correlation was found between the infection status of the orchard and the infection rate of overwintered C. picta. No influence of agricultural practices was seen. However, a relationship between the incidence of the disease and the vector population density became evident on a regional scale. Successful transmission of ‘Ca. P. mali’ occurred each year with overwintered individuals as well as with new adults. The transmission efficiency varied among the years within 8 to 45% for overwintered adults and 2 to 20% for individuals of the new generation. The load of single C. picta with ‘Ca. P. mali’ was determined by quantitative real-time PCR. High phytoplasma titers were measured in overwintered adults already at their first appearance in the orchards after remigration from their overwintering hosts. Thus, the data indicate the transmission of the disease on a regional scale by remigrant adults of C. picta and at a local scale within the same season by emigrant adults which developed on infected plants.

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Surveying Potential Vectors of Apple Proliferation Phytoplasma: Faunistic Analysis and Infection Status of Selected Auchenorrhyncha Species

Insects ◽

10.3390/insects12010012 ◽

2020 ◽

Vol 12 (1) ◽

pp. 12

Author(s):

Stefanie Fischnaller ◽

Martin Parth ◽

Manuel Messner ◽

Robert Stocker ◽

Christine Kerschbamer ◽

...

Keyword(s):

New Records ◽

Regional Scale ◽

Insect Vectors ◽

Infection Status ◽

Apple Proliferation ◽

Population Densities ◽

South Tyrol ◽

Candidatus Phytoplasma Mali ◽

Cacopsylla Melanoneura

Apple proliferation (AP) is one of the economically most important diseases in European apple cultivation. The disease is caused by the cell-wall-less bacterium ’ Candidatus Phytoplasma mali’, which is transmitted by Cacopsylla picta (Foerster) and Cacopsylla melanoneura (Foerster) (Hemiptera: Psylloidea). In South Tyrol (Italy), severe outbreaks were documented since the 1990s. Infestation rates of AP do not always correlate with the population densities of the confirmed vectors, implying the presence of other, so far unknown, hemipterian vectors. By elucidating the species community of Auchenorrhyncha (Insecta: Hemiptera) at a regional scale, more than 31,000 specimens were captured in South Tyrolean apple orchards. The occurrence of 95 species was confirmed, whereas fourteen species are new records for this territory. Based on the faunistical data, more than 3600 individuals out of 25 species were analyzed using quantitative PCR to assess the presence of AP phytoplasma. The pathogen was sporadically detected in some individuals of different species, for example in Stictocephala bisonia Kopp and Yonk (Hemiptera: Membracidae). However, the concentration of phytoplasma was much lower than in infected C. picta and C. melanoneura captured in the same region, confirming the role of the latter mentioned psyllids as the main insect vectors of AP- phytoplasma in South Tyrol.

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Long‐term maintenance of nonculturable apple‐proliferation phytoplasmas in their micropropagated natural host plant

Plant Pathology ◽

10.1046/j.1365-3059.1996.d01-171.x ◽

1996 ◽

Vol 45 (4) ◽

pp. 778-786 ◽

Cited By ~ 24

Author(s):

W. JARAUSCH ◽

M. LANSAC ◽

F. DOSBA

Keyword(s):

Host Plant ◽

Natural Host ◽

Apple Proliferation ◽

Term Maintenance

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Effect of Daytime and Tree Canopy Height on Sampling of Cacopsylla melanoneura, a ‘Candidatus Phytoplasma mali’ Vector

Plants ◽

10.3390/plants9091168 ◽

2020 ◽

Vol 9 (9) ◽

pp. 1168 ◽

Cited By ~ 2

Author(s):

Dana Barthel ◽

Christine Kerschbamer ◽

Bernd Panassiti ◽

Igor Malenovský ◽

Katrin Janik

Keyword(s):

Apple Tree ◽

Tree Canopy ◽

Temperature Threshold ◽

Insect Vector ◽

Apple Proliferation ◽

Candidatus Phytoplasma Mali ◽

Cacopsylla Melanoneura ◽

Cacopsylla Pruni ◽

Vector Behavior ◽

Practical Impact

The psyllids Cacopsylla melanoneura and Cacopsylla picta reproduce on apple (Malus × domestica) and transmit the bacterium ‘Candidatus Phytoplasma mali’, the causative agent of apple proliferation. Adult psyllids were collected by the beating-tray method from lower and upper parts of the apple tree canopy in the morning and in the afternoon. There was a trend of catching more emigrant adults of C.melanoneura in the morning and in the lower part of the canopy. For C.melanoneura remigrants, no differences were observed. The findings regarding the distribution of adults were reflected by the number of nymphs collected by wash-down sampling. The density of C.picta was too low for a statistical analysis. The vector monitoring and how it is commonly performed, is suitable for estimating densities of C.melanoneura. Nevertheless, above a certain temperature threshold, prediction of C.melanoneura density might be skewed. No evidence was found that other relatively abundant psyllid species in the orchard, viz. Baeopelma colorata, Cacopsylla breviantennata, Cacopsylla brunneipennis, Cacopsylla pruni and Trioza urticae, were involved in ‘Candidatus Phytoplasma mali’ transmission. The results of our study contribute to an advanced understanding of insect vector behavior and thus have a practical impact for an improved field monitoring.

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Apple Proliferation Resistance in Apomictic Rootstocks and Its Relationship to Phytoplasma Concentration and Simple Sequence Repeat Genotypes

Phytopathology ◽

10.1094/phyto-98-2-0153 ◽

2008 ◽

Vol 98 (2) ◽

pp. 153-158 ◽

Cited By ~ 28

Author(s):

C. Bisognin ◽

B. Schneider ◽

H. Salm ◽

M. S. Grando ◽

W. Jarausch ◽

...

Keyword(s):

Simple Sequence Repeat ◽

Natural Infection ◽

Dna Typing ◽

Type I ◽

Type Ii ◽

Apple Proliferation ◽

Sequence Repeat ◽

Candidatus Phytoplasma Mali ◽

High Level ◽

Simple Sequence

In an effort to select and characterize apple rootstock resistant to apple proliferation (AP), progenies from seven apomictic rootstock selections and their parental apomictic species, Malus sieboldii and M. sargentii, were compared to standard stocks M 9 and M 11. Seedlings derived from open pollinated mother plants were grafted with cv. Golden Delicious and grown under natural infection conditions. The progenies differed greatly in resistance to the AP agent ‘Candidatus Phytoplasma mali’. Progenies of M. sieboldii and its descendent rootstock selections D2212, 4608, 4551, and D1131 showed a high level of resistance, whereas progenies of M. sargentii and its descendent selections D1111 and C1828 proved susceptible. M 9 and M 11 showed an intermediate level of resistance. Phytoplasma titer in roots of the M. sieboldii and M. sargentii progeny groups was similarly low, whereas the concentration in the standard stocks was 100 to 5,000 times higher. In trees on most of the resistant stocks, only a minority was colonized in the scion, while in trees on susceptible and standard stocks, infection rate was often higher. Also, the titer in the top of trees on resistant stocks was usually lower than in trees on susceptible and standard stocks. Four progenies derived from open pollinated M. sieboldii and M. sieboldii descendents were subjected to DNA typing using simple sequence repeat (SSR) markers. This study revealed that the selected groups consisted mainly of mother-like plants (apomicts) and type I hybrids (unreduced mother genotype plus one male allele at each locus). Type II hybrids (full recombinants) and autopollinated offspring were rare. In the 4608 progeny, trees grown on type I hybrid rootstocks were significantly less affected than trees on mother-like stocks. In other progenies with fewer or no type I hybrids, trees on type II hybrids and autopollinated offspring suffered considerably more from disease than trees on mother-like stocks.

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Morphometric studies of artemia males from different populations of the Altai region

Rybovodstvo i rybnoe hozjajstvo (Fish Breeding and Fisheries) ◽

10.33920/sel-09-2007-03 ◽

2020 ◽

pp. 28-38

Author(s):

L. Vesnina ◽

G. Lukerina ◽

T. Ronzhina ◽

A. Savos’kin ◽

D. Surkov

Keyword(s):

Sexual Dimorphism ◽

Hydrogen Index ◽

Morphometric Parameters ◽

Altai Region ◽

Sexual Structure ◽

Different Populations ◽

Artemia Population ◽

Term Data ◽

Brine Salinity

The long-term data from morphometric studies of Artemia males from bisexual and parthenogenetic populations from hyperhaline reservoirs of the Altai region (Bolshoe Yarovoe Lake, Maloe Shklo Lake, and the Tanatar Lakes system) is analyzed in this paper. The description of signs of sexual dimorphism and sexual structure in different populations is given. The influence of brine salinity and hydrogen index on morphometric parameters of males was analyzed. There are differences in the sexual structure of the Artemia population: in the lakes Maloe Shklo and the thanatar system, the populations are bisexual (the share of males is 28.5 — 75.0 %), in the lake Bolshoe yarovoe — parthenogenetic (the share of males on average does not exceed 3 %). At the same time, sexual dimorphism is typical for both types of populations: females are larger than males, males have a larger head (the distance between the eyes is greater by 15.5 %, the diameter of the eye is 26.1 %, the length of the antenna is 22.3 %) and a larger number of bristles (36.1 %). The greatest variability is observed in the parameters of the Furka structure associated with the salinity of water by feedback and the pH — line indicator. Significant differences between the samples of males were revealed. The largest number of significant differences in morphometric indicators was found between samples of males from bisexual populations (lake thanatar and lake Maloe Shklo), the smallest — between males from the parthenogenetic population of lake Bolshoe yarovoe and males from lake Maloe Shklo.

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Effectiveness of a Comprehensive Hand Hygiene Program for Reduction of Infection Rates in a Long-Term Care Facility: Lessons Learned

American Journal of Infection Control ◽

10.1016/j.ajic.2012.04.265 ◽

2012 ◽

Vol 40 (5) ◽

pp. e149 ◽

Cited By ~ 2

Author(s):

Steven Schweon ◽

Sarah Edmonds ◽

Jane M. Kirk ◽

Douglas Y. Rowland

Keyword(s):

Hand Hygiene ◽

Long Term Care ◽

Care Facility ◽

Lessons Learned ◽

Infection Rates ◽

Term Care ◽

Term Care Facility ◽

Long Term Care Facility

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

Insects ◽

10.3390/insects11090592 ◽

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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