Life cycle variation of Myzus persicae (Hemiptera: Aphididae) in Greece

2002 ◽  
Vol 92 (4) ◽  
pp. 309-319 ◽  
Author(s):  
J.T. Margaritopoulos ◽  
J.A. Tsitsipis ◽  
S. Goudoudaki ◽  
R.L. Blackman
Keyword(s):  
Life Cycle ◽  
Myzus Persicae ◽  
Host Plants ◽  
Primary Host ◽  
Low Frequencies ◽  
Cycle Variation ◽  
Ecological Aspects ◽  
North Eastern ◽  
Winter Crops ◽  
Almost All

AbstractDuring the years 1995–1999 the life cycle category of 2797 clones of Myzus persicae (Sulzer) was examined. The clones originated from primary and secondary hosts from different localities of North and Central Greece and the island of Crete in the south. Four different overwintering life cycle strategies were found that have also been described for M. persicae and other heteroecious species previously. A geographical variation was found in the proportion of holocyclic clones from tobacco and other secondary hosts associated with the abundance of the primary host in the sampling regions. In Central Macedonia, around the main peach-growing regions, the proportion of holocyclic clones was mostly above 50% and in some cases reached 100%. In localities of East Macedonia, holocyclic clones were also frequent. On the other hand, further south or in north-eastern Greece, where peach is not common, the proportion of holocyclic clones varied between 0 and 33%. Fifty seven percent of examined anholocyclic clones produced males under short day conditions, suggesting that androcyclic clones in Greece represent an important factor of genetic variability. Intermediate clones were sampled from all host-plants but at low frequencies (3.6% of total examined clones and 6.9% of non-holocyclic ones). Moreover, a regional variation was found in different colour forms feeding on tobacco plants. Red clones were predominant in regions where aphids overwinter parthenogenetically on weeds or winter crops. However, almost all clones from the primary host were green. The ecological aspects of life cycle variation are discussed.

Variation in the life cycle and morphology of the tobacco host-race of Myzus persicae (Hemiptera: Aphididae) in relation to its geographical distribution

2002 ◽  
Vol 92 (4) ◽  
pp. 301-307 ◽  
Author(s):  
T.E. Kephalogianni ◽  
J.A. Tsitsipis ◽  
J.T. Margaritopoulos ◽  
E. Zintzaras ◽  
R. Delon ◽  
...  
Keyword(s):  
Life Cycle ◽  
Morphological Variation ◽  
Myzus Persicae ◽  
Western Europe ◽  
Classification Tree ◽  
Primary Host ◽  
Canonical Variates Analysis ◽  
Parametric Classification ◽  
Canonical Variates ◽  
Tree Method

AbstractMorphological variation and life cycle category were examined in 121 clones of Myzus persicae (Sulzer). The clones were collected from tobacco from three localities in Greece (Xanthi, Nea Efessos and Naphplion), one in Germany (Rheinstetten), one in France (Bergerac) and one in Spain (Madrid). Before morphometrics, all aphids were laboratory-reared on potato. The morphological variation was investigated using both canonical variates analysis and a novel non-parametric classification tree method. The life cycle category was examined by rearing the clones for three generations under short day conditions. In Nea Efessos a relative high proportion of clones was found to overwinter as eggs on the primary host. In the other regions all collected clones were non-holocyclic. Intermediate genotypes were found in all regions at percentages ranging from 4.0 to 24.0%. Androcyclic clones were found only in Xanthi, Greece (4.0%) and Rheinstetten, Germany (16.7%). The canonical variates analysis and the tree classification method revealed important intrapopulation polymorphisms in clones from Bergerac, Nea Efessos and Madrid. Both methods separated the populations originating from Greece from those collected elsewhere in western Europe. The observed morphological variation was probably due to genetic differences, since all clones were reared in a common environment. The results are discussed in relation to factors responsible for genetic divergence in M. persicae populations.

scholarly journals Pear rust in the conditions of north-eastern Forest-Steppe of Ukraine

2019 ◽  
pp. 53-58
Author(s):  
V.I. Tatarynova ◽  
O.G. Zhatov ◽  
V.I. Trotsenko ◽  
A.O. Burdulanyuk ◽  
T.O. Rozhkova ◽  
...  
Keyword(s):  
Life Cycle ◽  
Weather Conditions ◽  
Forest Steppe ◽  
The North ◽  
North Eastern ◽  
Different Types ◽  
Pear Trees ◽  
Fruit Orchards ◽  
Almost All ◽  
Gymnosporangium Sabinae

Studies were conducted during 2017‒2019 based on the training laboratory of horticulture and viticulture of the Sumy National Agrarian University in the conditions of the North-Eastern Forest-Steppe of Ukraine. It was found that the pear was massively affected by rust. This is a fungal disease that was rarely found in fruit orchards of the North-Eastern Forest-Steppe of Ukraine. Rust infected pear trees very rarely in previous years. Only single spots were found on the leaves of the pear. Since 2015, the development of the disease has noticeably accelerated from year to year. There was a massive rust damage of the pear in the region in 2019. The prevalence of the disease reached 100 % in almost all varieties. Mostly the leaves were affected, not to a large extent the shoots of the pear. On the fruits of the external signs of the disease were not detected. During the years of research, weather conditions were optimal for the spread of fungal diseases. Only the aecial stage of the fungus was observed on the pear.  The aecial stage of the pathogen is the most harmful. Affected pear leaves fall prematurely. Studies were conducted on pear varieties Lymonka, Petrovska, Medova, Osinnia Yakovlieva, Chyzhovska, Noiabrska, Bere Desiatova, Uliublenytsia Klappa, which showed different degrees of rust damage. The disease manifested itself most significantly (5 points) on the varieties, Uliublenytsia Klappa and Bere Desiatova. Not one of the varieties did not show high resistance to the pathogen. The pear of the Chyzhovska variety was less affected, with a defeat score of 3 (18.8 %) in 2017 and 4 (32.3 % and 44.1 %) in 2018‒2019. It is known that the life cycle of the rust pathogen Gymnosporangium sabinae (Dicks.) G. Winter occurs on two plants: pear and juniper. The pathogen from juniper goes on the pear and vice versa. Pear trees do not become infected from each other. On the territory adjacent to the fruit garden of Sumy National Agrarian University, a survey of plantings of different types of juniper was conducted. There were no visible signs of the disease on the juniper. At the same time, pear trees were highly infected with the pathogen. Perhaps the spores of the fungus can spread far through air currents. But at the same time, possible changes in the life cycle of the pathogen in the conditions of this region. Clarification of this circumstance requires deeper further research.

Life-cycle variation of Myzus persicae (Sulz.) (Hom., Aphididae) in different parts of the world, in relation to genotype and environment

1974 ◽  
Vol 63 (4) ◽  
pp. 595-607 ◽  
Author(s):  
R. L. Blackman
Keyword(s):  
Life Cycle ◽  
Sexual Reproduction ◽  
Myzus Persicae ◽  
Alternative Methods ◽  
Global Pattern ◽  
Sexual Morph ◽  
Cycle Variation ◽  
Genotype Frequencies ◽  
The World ◽  
Different Parts

AbstractLife-cycle variation, involving alternative methods of overwintering (holocycly and anholocycly), is found in many important pest aphids, and may have considerable ecological, genetic and economic significance. The occurrence of life-cycle variation in Myzus persicae (Sulz.) in different parts of the world is reviewed. The holocycle of M. persicae, with sexual reproduction and overwintering of eggs on Prunus, occurs in the temperate regions of every continent, and although anholocycly is widespread in warm climates there are indications that the potential for sexual reproduction may be retained throughout the whole range of the species. The environmental factors involved in the determination of sexual morphs are considered. Photoperiodism provides the timing mechanism for sexual morph production, and the photoperiodic response is probably tuned to different regional conditions and buffered against other environmental variables within certain limits. The only other environmental factor clearly implicated in sexual morph production is temperature, and an attempt is made to correlate the global pattern of life-cycle variation in M. persicae with temperature differences between regions, by dividing the world into six zones delimited by selected isotherms. The overall pattern of life-cycle variation can be explained largely on the basis of climatic differences between zones, and the effects of these differences on gene and genotype frequencies within the species. Clones of androcyclic character seem to be widespread and, although genetically isolated anholocyclic biotypes undoubtedly exist, androcyclic clones could be the principal source of parthenogenetic overwinterers in all parts of the world where life-cycle differences exist within populations.

Inferring the population structure of Myzus persicae in diverse agroecosystems using microsatellite markers

2013 ◽  
Vol 103 (4) ◽  
pp. 473-484 ◽  
Author(s):  
Juan Antonio Sanchez ◽  
Michelangelo La-Spina ◽  
Pedro Guirao ◽  
Fernando Cánovas
Keyword(s):  
Population Structure ◽  
Myzus Persicae ◽  
Host Plants ◽  
Climatic Conditions ◽  
Genetic Population Structure ◽  
The South ◽  
Primary Host ◽  
Genetic Population ◽  
The North ◽  
Plant Families

AbstractDiverse agroecosystems offer phytophagous insects a wide choice of host plants. Myzus persicae is a polyphagous aphid common in moderate climates. During its life cycle it alternates between primary and secondary hosts. A spatial genetic population structure may arise due to environmental factors and reproduction modes. The aim of this work was to determine the spatial and temporal genetic population structure of M. persicae in relation to host plants and climatic conditions. For this, 923 individuals of M. persicae collected from six plant families between 2005 and 2008 in south-eastern Spain were genotyped for eight microsatellite loci. The population structure was inferred by neighbour-joining, analysis of molecular variance (AMOVA) and Bayesian analyses. Moderate polymorphism was observed for the eight loci in almost all the samples. No differences in the number of alleles were observed between primary and secondary hosts or between geographical areas. The proportion of unique genotypes found in the primary host was similar in the north (0.961 ± 0.036) and the south (0.987 ± 0.013), while in the secondary host it was higher in the north (0.801 ± 0.159) than in the south (0.318 ± 0.063). Heterozygosity excess and linkage disequilibrium suggest a high representation of obligate parthenogens in areas with warmer climate and in the secondary hosts. The FST-values pointed to no genetic differentiation of M. persicae on the different plant families. FST-values, AMOVA and Bayesian model-based cluster analyses pointed to a significant population structure that was related to primary and secondary hosts. Differences between primary and secondary hosts could be due to the overrepresentation of parthenogens on herbaceous plants.

TUNGAU PADA DAUN MANGGA (Mangifera Indica)

2014 ◽  
Vol 13 (3) ◽  
Author(s):  
Rawati Panjaitan
Keyword(s):  
Life Cycle ◽  
Direct Observation ◽  
Host Plants ◽  
Body Shape ◽  
Leaf Surface ◽  
Mangifera Indica ◽  
Posterior Part ◽  
Mango Leaves

Mites have hostplant specifications or host plants. Mites can be destructive and deadly of which is the host plants a mango crop. Mites on mango crops will cause the leaves yellow and fall off prematurely. This is will lead to the disruption of the productivity of mango. It is necessary for research to identify the mites that infect the mango crop. The method is carried out by direct observation. Mites were taken from the surface of mango leaves later in preservation with several levels of concentration of alcohol, and polyvinyl laktofenol. Then, observed under a microscope and documented for identification purposes. Mites on the leaf surface of manalagi mango (<em>Mangifera indica</em>) found two species, it is <em>Oligonychus</em> sp. and <em>Oligonychus ilicis</em> (Family: Tetranychidae, Superfamily: Tetranychoidea). <em>Oligonychus</em> sp. hallmark is rounded body shape like a spider, with a body is transparent and there are two long seta on posterior part. While <em>Oligonychus ilicis</em> has a characteristic elongated rounded body shape, red, and there is a short posterior seta. <em>Oligonychus</em> sp. and <em>Oligonychus ilicis</em> live as parasites on the surface of mango leaves that can lead to wrinkled leaves, yellow and to fall. <em>Oligonychus</em> life cycle starts from the eggs develop into Nympha and then adult.

scholarly journals CAD integrated automatic recognition of weld paths

2021 ◽  
Author(s):  
Tuan Anh Tran ◽  
Andrei Lobov ◽  
Tord Hansen Kaasa ◽  
Morten Bjelland ◽  
Ole Terje Midling
Keyword(s):  
Life Cycle ◽  
Spatial Analysis ◽  
Product Life Cycle ◽  
Real Life ◽  
Automatic Recognition ◽  
Integrated Method ◽  
Weld Joints ◽  
Related Information ◽  
Almost All ◽  
Sequential Assembly

AbstractIn this paper, a CAD integrated method is proposed for automatic recognition of potential weld locations in large assembly structures predominantly comprised of weld joints. The intention is to reduce the total man-hours spent on manually locating, assigning, and maintaining weld-related information throughout the product life cycle. The method utilizes spatial analysis of extracted stereolithographic data in combination with available CAD functions to determine whether the accessibility surrounding a given intersection edge is sufficient for welding. To demonstrate the method, a system is developed in Siemens NX using their NXOpen Python API. The paper presents the application of the method to real-life use cases in varying complexity in cooperation with industrial partners. The system is able to correctly recognize almost all weld lines for the parts considered within a few minutes. Some exceptions are known for particular intersection lines located deep within notched joints and geometries weldable through sequential assembly, which are left as a subject to further works.

Variation in Myzus persicae (Sulz.) (Hemiptera, Aphididae) reared on different host-plants

1973 ◽  
Vol 62 (4) ◽  
pp. 549-556 ◽  
Author(s):  
H. J. B. Lowe
Keyword(s):  
Young Adults ◽  
Sugar Beet ◽  
Chinese Cabbage ◽  
Lactuca Sativa ◽  
Myzus Persicae ◽  
Host Species ◽  
Host Plants ◽  
Broad Bean ◽  
Senecio Vulgaris ◽  
Brassica Pekinensis

Apterous adult Myzus persicae (Sulz.) of a glasshouse strain differed greatly in their ability to colonise sugar-beet according to the plant on which they and their forebears were cultured. Those from Chinese cabbage (Brassica pekinensis) settled least readily on beet, whilst aphids from broad beans (Vicia faba) produced larger populations than those cultured on sugar-beet. When reared wholly on groundsel (Senecio vulgaris) young adults differed in their ability to colonise Chinese cabbage, sugar-beet and broad bean according to their parents' culture host species, and these differences were detected in a second generation reared wholly on groundsel. The responses of clones isolated from cultures maintained continuously on Chinese cabbage and broad bean were similar, showing that the effect was caused by the aphids' host-plant experience, and was not due to fixed, heritable characters of the sub-cultures. Some, but not all clones of M. persicae collected from the field showed enhanced colonising ability after culture on broad bean as compared with Chinese cabbage. This was apparent on sugar-beet and lettuce (Lactuca sativa). These effects of former hosts on the ability of M. persicae to colonise plants may be important both in work on resistance to aphids and in the epidemiology of aphid-borne diseases.

Descriptive and illustrated diagnosis of Ophiuroidea fauna (Echinodermata) in the shallow waters of North-eastern Brazil

2015 ◽  
Vol 8 ◽  
Author(s):  
Fabilene Gomes Paim ◽  
Maria Cecília Guerrazzi ◽  
Michela Borges
Keyword(s):  
Brittle Star ◽  
Shallow Waters ◽  
Bottom Substrate ◽  
Eastern Brazil ◽  
North Eastern ◽  
Amphipholis Squamata ◽  
Biological Substrates ◽  
Almost All ◽  
First Time ◽  
Ophiocoma Echinata

In this study, we present descriptions, illustrations, comments, and bathymetric and geographic distributions of the brittle star species related to the estuary region of Camamu Bay, located in the State of Bahia, Brazil. The brittle star fauna lives on biological substrates, sand bottoms, mud and rubble in the Camamu Bay and comprises 12 species divided into five families. Almost all of them are common in the tropical and subtropical fauna of the regions of shallow water.Ophiophragmus filograneusis reported for the first time in Bahia, and nine other species are recorded for the first time in Camamu Bay:Amphipholis januarii, Amphipholis squamata, Ophiophragmus filograneus, Ophiostigma isocanthum,Ophioderma cinerea, Ophioderma januarii, Ophiactis lymani, Ophiactis savignyi andOphiocoma echinata.The results suggest that the ophiuroid assemblages are strongly affected by marine currents as well as by different kinds of bottom substrate.

The inheritance of life-cycle differences in Myzus persicae (Sulz.) (Hem., Aphididae)

1972 ◽  
Vol 62 (2) ◽  
pp. 281-294 ◽  
Author(s):  
R. L. Blackman
Keyword(s):  
Life Cycle ◽  
Myzus Persicae ◽  
Imperial College ◽  
Short Photoperiod ◽  
Male Production ◽  
Field Station ◽  
Heterozygous Condition ◽  
Segregation Ratios ◽  
Genetically Determined

The response to short photoperiod (10 h) of the F1 and F2 sexual generations of Myzus persicae (Sulz.) resulting from a cross between oviparae from a holocyclic clone and males from an androcyclic clone were examined and compared in experiments done at Imperial College Field Station, England. F1 and F2 progeny segregated into three distinct phenotypes; holocyclic, androcyclic and intermediate. Intermediate clones reared at 10 h photoperiod produced alatae which were physiologically intermediate between gynoparae and virginoparae, because their progeny consisted of oviparae, apterous virginoparae and intermorphs. Intermediacy was not affected by temperature and seems to be genetically determined. Segregation ratios in the F1 and F2 indicate that the androcyclic condition is induced by a recessive ‘ switch-gene ’ which completely suppresses the production of sexual females, and partially suppresses male production. This gene could be present in the heterozygous condition in a large proportion of parthenogenetic lines of the aphid, and thus confer a latent potentiality for anholocycly on populations even where conditions will not regularly permit this method of overwintering. Conversely where anholocycly is strongly favoured many aphids would be homozygous for the recessive, androcyclic character, but the potential for gamic reproduction could remain widespread.

Ireland: Coalition Politics in a Fragmenting Party System

2021 ◽  
pp. 357-395
Author(s):  
Paul Mitchell
Keyword(s):  
Life Cycle ◽  
Party System ◽  
Coalition Government ◽  
Limited Government ◽  
Coalition Governments ◽  
Coalition Politics ◽  
System P ◽  
Fianna Fail ◽  
The Government ◽  
Almost All

Ireland is a parliamentary democracy created as a result of a revolutionary secession from the United Kingdom. While Ireland has many institutional and administrative features that are quite similar to the Westminster model, there are also some important departures, most notably the adoption of limited government via a written constitution, and the adoption of PR-STV which has facilitated the formation of coalition governments. For most of the twentieth century (up until 1989 at least) a Fianna Fáil single-party government was the default outcome of the government-formation process, though many of these cabinets were ‘large’ minority administrations. The only method of ejecting Fianna Fáil was for the second- and third-largest parties (Fine Gael and Labour) to form a coalition government, which they did on a number of occasions. The bargaining environment permanently changed in 1989 when Fianna Fáil broke the habit of a lifetime and entered its first coalition with the Progressive Democrats. Since then almost all governments have been coalitions. This chapter examines the life cycle of coalition government in Ireland: formation, governance, and dissolution. Coalition agreements have evolved over the decades and have become much more important, detailed, and hence more lengthy. The coalition programme plays a key role in the work of the cabinet and the relations between the parties. The increasingly detailed coalition agreements are a very important commitment device during the life cycle of coalition governments. The increasing fragmentation of the party system has meant that coalition formation bargaining has become more challenging.

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