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

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1168 ◽  
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.

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

Insects ◽  
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.

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.

scholarly journals A Novel Effector Protein of Apple Proliferation Phytoplasma Disrupts Cell Integrity of Nicotiana spp. Protoplasts

2019 ◽  
Vol 20 (18) ◽  
pp. 4613 ◽  
Author(s):  
Cecilia Mittelberger ◽  
Hagen Stellmach ◽  
Bettina Hause ◽  
Christine Kerschbamer ◽  
Katja Schlink ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Effector Proteins ◽  
Plant Diseases ◽  
Effector Protein ◽  
Insect Vector ◽  
Cell Integrity ◽  
Apple Proliferation ◽  
Disease Manifestation ◽  
Candidatus Phytoplasma Mali ◽  
Exact Function

Effector proteins play an important role in the virulence of plant pathogens such as phytoplasma, which are the causative agents of hundreds of different plant diseases. The plant hosts comprise economically relevant crops such as apples (Malus × domestica), which can be infected by ‘Candidatus Phytoplasma mali’ (P. mali), a highly genetically dynamic plant pathogen. As the result of the genetic and functional analyses in this study, a new putative P. mali effector protein was revealed. The so-called “Protein in Malus Expressed 2” (PME2), which is expressed in apples during P. mali infection but not in the insect vector, shows regional genetic differences. In a heterologous expression assay using Nicotiana benthamiana and Nicotiana occidentalis mesophyll protoplasts, translocation of both PME2 variants in the cell nucleus was observed. Overexpression of the effector protein affected cell integrity in Nicotiana spp. protoplasts, indicating a potential role of this protein in pathogenic virulence. Interestingly, the two genetic variants of PME2 differ regarding their potential to manipulate cell integrity. However, the exact function of PME2 during disease manifestation and symptom development remains to be further elucidated. Aside from the first description of the function of a novel effector of P. mali, the results of this study underline the necessity for a more comprehensive description and understanding of the genetic diversity of P. mali as an indispensable basis for a functional understanding of apple proliferation disease.

scholarly journals Phytoplasma diseases on fruits in Hungary

2014 ◽  
pp. 24-29
Author(s):  
Sándor Süle
Keyword(s):  
Host Plants ◽  
Apple Proliferation ◽  
Japanese Plum ◽  
Candidatus Phytoplasma Mali ◽  
Cacopsylla Pruni ◽  
Almost All ◽  
Insecticide Control ◽  
Important Disease ◽  
Candidatus Phytoplasma Prunorum ◽  
Organic Orchards

In the last twenty years, three phytoplasma diseases were identified in Hungary, viz. European Stone Fruit Yellows (ESFY) (caused by Candidatus Phytoplasma prunorum), pear decline (caused by Candidatus Phytoplasma pyri), and apple proliferation (caused by Candidatus Phytoplasma mali). Candidatus Phytoplasma prunorum was isolated from apricot, peach, plum and japanese plum. Cacopsylla pruni the vector of ESFY was also isolated and identified. Infection of Candidatus Phytoplasma pyri was diagnosed from pear and Candidatus Phytoplasma mali was found on apple and pear. The three phytoplasmas cause different damages on their host plants. The most economically important phytoplasma disease is the ESFY. It seriously impairs apricot and japanase plum trees. After infection of apricots and japanese plums show yellowing and defoliation, and within a few years die in apoplexy-like symptoms. The disease on japanese plum is so severe that this fruit practically can not be cultivated in Hungary. Pear decline is the most serious problem especially in intensive pear plantations. The vector Cacopsylla pyri, C. pyrisuga and C. pyricola can be found in almost all pear orchards. Because of the regular presence of psyllids in intensive pear orchards the insecticide control is necessary. Apple proliferation is not an important disease in Hungary. All of our isolations of ’Candidatus Phytoplasma mali’ occured in organic orchards and record was not available in Hungary lately.

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

2009 ◽  
Vol 99 (6) ◽  
pp. 729-738 ◽  
Author(s):  
Christoph J. Mayer ◽  
Barbara Jarausch ◽  
Wolfgang Jarausch ◽  
Wilhelm Jelkmann ◽  
Andreas Vilcinskas ◽  
...  
Keyword(s):  
Host Plant ◽  
Natural Infection ◽  
Infected Individual ◽  
Apple Proliferation ◽  
Infection Rates ◽  
Northern Switzerland ◽  
Candidatus Phytoplasma Mali ◽  
Cacopsylla Melanoneura ◽  
Different Populations

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.

Hyperspectral Evaluation of SPAD Value of Apple Tree Canopy Based on Continuum-Removed Method

2016 ◽  
Vol 53 (2) ◽  
pp. 023001 ◽  
Author(s):  
韩兆迎 Han Zhaoying ◽  
朱西存 Zhu Xicun ◽  
王凌 Wang Ling ◽  
赵庚星 Zhao Gengxing
Keyword(s):  
Apple Tree ◽  
Tree Canopy ◽  
Spad Value

Apple tree canopy development and photosynthesis as affected by rootstock

1991 ◽  
Vol 69 (2) ◽  
pp. 295-300 ◽  
Author(s):  
Ido Schechter ◽  
D. C. Elfving ◽  
J. T. A. Proctor
Keyword(s):  
Malus Domestica ◽  
Apple Tree ◽  
Net Photosynthesis ◽  
Light Interception ◽  
Tree Canopy ◽  
Seasonal Development ◽  
Hemispherical Photography ◽  
Canopy Development ◽  
Leaf Type ◽  
Malus Domestica Borkh

Trees of apple (Malus domestica Borkh.) with 'Starkspur Supreme Delicious' as the scion grafted on nine different rootstocks (Ottawa 3, M.7 EMLA, M.9 EMLA, M.26 EMLA, M.27 EMLA, M.9, MAC-9, MAC-24, OAR 1) were studied in their 8th and 9th years. Canopy seasonal development and its light interception followed by fisheye (hemispherical) photography showed that rootstock affected the amount of structural wood, the rate of canopy development, and final leaf area. However, rootstock did not affect the sigmoidal pattern of canopy development. Light interception was linearly correlated with tree dimensions and yield. Leaf net photosynthesis (Pn) of trees on dwarfing rootstocks tended to be lower than Pn rates of trees on more vigorous rootstocks. Rootstock did not affect the scion Pn response to different illumination levels. Shoot leaves, spur leaves on spurs without fruit (S − F), and spur leaves on spurs with fruit (S + F) from trees on M.26 EMLA and OAR 1 showed no differences in Pn rates. However, for both rootstocks, shoot leaves had the highest Pn rate, S + F the lowest, and S − F leaves had intermediate values. Key words: light interception, fisheye photography, leaf type.

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