The Betula aphids of Turkey

To date, about 400 aphid species have been recorded in Turkey (see References). However, this is the first paper which 3 aphid species determined in 3 genera on Betula spp. in Turkey. These species, namely Calaphis flava Mordvilko, Callipterinella calliptera (Hartig) and Euceraphis punctipennis (Zetterstedt) all belong to the family: Aphididae, subfamily: Myzocallinae, tribe: Calaphini and none of the species has previously been recorded in aphid fauna lists on Betula spp. in Turkey. Their synonyms, morphological characteristics and biological data, supported by literature, were also considered.     

The Betula aphids of Turkey

To date, about 400 aphid species have been recorded in Turkey (see References). However, this is the first paper which 3 aphid species determined in 3 genera on Betula spp. in Turkey. These species, namely Calaphis flava Mordvilko, Callipterinella calliptera (Hartig) and Euceraphis punctipennis (Zetterstedt) all belong to the family: Aphididae, subfamily: Myzocallinae, tribe: Calaphini and none of the species has previously been recorded in aphid fauna lists on Betula spp. in Turkey. Their synonyms, morphological characteristics and biological data, supported by literature, were also considered.     

Biological features and life table parameters of the mealy plum aphidHyalopterus pruni on different apricot cultivars

Development, survival, reproduction rate, and population growth parameters of the mealy plum aphidHyalopterus pruni (Geoffroy) (Hom.: Aphididae) were evaluated on four different apricot cultivars (Tyrinte, Sakıt, Colomer, and Bebeco) under field conditions in the Van region of Turkey. Experiments were carried out on exterior leaves of trees, 1.5–2 m above the ground. Plexiglas clip-cells (25×6 mm) with the upper side covered by muslin were used in the experiments. The mealy plum aphid performed better on Tyrinte than on the other cultivars tested. The fastest development time (first instar to adult; 9.4 days), highest daily reproduction rate (2.6 offspring/aphid/day), and highest total fecundity (48.1 offspring/aphid) were obtained on Tyrinte. The intrinsic rate of increase — a good indicator of the growth potential of a population — of individuals fed on Tyrinte was significantly greater than that of individuals fed on cvs. Colomer and Bebeco. While mean generation times (T _o ) of populations on different cultivars were close to each other, the net reproductive rate was the highest (29.45 offspring/aphid/generation) on Tyrinte and the population doubling time on Tyrinte was 18.7%, 25.2% and 26.3% faster than those of individuals on other cultivars tested. The results obtained in this study indicated that Tyrinte appeared to be the most susceptible to the mealy plum aphid among the cultivars tested. http://www.phytoparasitica.org. posting Nov. 23, 2004.     

Bacteria from four phylogroups of the Pseudomonas syringae complex can cause bacterial canker of apricot

Pseudomonas syringae is described as a species complex, containing P. syringae-related species classified into 13 phylogroups and 23 clades. Pseudomonas syringae is one of the main pathogens of fruit trees, affecting nut trees, hazelnut and kiwi, pome and stone fruits. Bacterial canker of apricots is an important disease in regions of production with cold winters and conducive soils. This work characterizes the bacteria able to induce canker in apricots isolated in different French orchards. Bacteria from four phylogroups were able to induce canker. The pathogenicity to apricot was not linked to the pathogenicity to the three herbaceous species and cherry fruits tested, and was not always related to hypersensitive reaction on tobacco and ice nucleation activity. Bacteria pathogenic to apricot belong to phylogroups 01, 02, 03 and 07. The bacteria of phylogroups 01a and 07a (Pseudomonas viridiflava) characterized in this work have not previously been described as pathogenic to apricot.     

Epidemiology of sharka disease in Spain

PPV was first detected in Spain in 1984 in Japanese plum ( Prunus salicina Lindl) cv. Red Beaut and spread very quickly to other Japanese and European plums and apricot cultivars but left peach cultivars unaffected. In the years following the detection of PPV, the predominant aphid species visiting Prunus orchards in Mediterranean areas were Aphis gossypii followed by Aphis spiraecola , the latter being the main aphid species found at present. Both species are considered to be the main vectors of PPV in Spanish early Prunus growing areas. Spatial analysis of the spread of PPV-D in Japanese plum and apricot trees confirmed the lack of significant association between immediately adjacent trees. The observed spatial pattern of sharka suggests a lack of movement of PPV-viruliferous aphid vectors to immediately adjacent trees and indicates their preferential movement to trees several tree spaces away. PPV-D is the only type currently present in Spain, with the exception of a PPV-M outbreak that was detected in and successfully eradicated from Aragón in 2002. The short-distance spread of PPV-M infection occurred as far as 12 m along the rows of peach trees. However, PPV-D has not been observed to spread through peach cultivars, despite being grown in the vicinity of heavily infected plots of apricot or Japanese plum trees.     

Aphid and host plant species in the Arava Valley of Israel: Epidemiological aspects

A survey of aphid species which colonize or reproduce on wild and cultivated plants in the Arava Valley of Israel was carried out at the end of winter 1986. Thirty-three aphid species were collected on wild plants and 23 in green tile or yellow traps exposed in cultivated plots. Aphids were recorded from 77 plant species in 22 botanical families.Myzus persicae, Aphis craccivora, Brachyunguis harmalae, Acyrthosiphon gossypii andAphis gossypii were present on plants in 19 botanical families. M. persicae was the most frequently trapped aphid species in both green tile and yellow traps. The possible origin of the aphid species found in the desert was considered in view of the ecology and geography of the region. The role of aphid species trapped in the Arava Valley, in the epidemiology of potato virus Y (PVY) and zucchini yellow mosaic virus (ZYMV), is discussed. Publication of the Agricultural Research Organization. No. 2305-E, 1988 series.     

Note on <Emphasis Type="Italic">Wahlgreniella nervata</Emphasis> (Gillette, 1908) (Hemiptera: Aphididae): a new pest of Damask rose in Turkey

Alate viviparous females of Wahlgreniella nervata (Gillette) were found on a Damask rose (Rosa damascena Mill.) plantation in Isparta Province, Turkey. The aphid is recorded for the first time from Turkey. Besides, Damask rose is a new host for this species. Brief information about this aphid including a key to the alate females of aphid species known to infest Damask rose in Turkey is provided.     

New aphid vectors and efficiency of transmission of Potato virus A and strains of Potato virus Y in the UK

The aphid‐transmitted viruses Potato virus Y (PVY) and Potato virus A (PVA) commonly affect seed potatoes in the UK. The transmission efficiency for aphid species is used to calculate a potential transmission risk and is expressed as a relative efficiency factor (REF). These REFs have not previously been calculated for UK strains of viruses or aphid clones. Using a previously published method, REFs have been calculated for the aphid species and viruses commonly occurring in UK potatoes. The efficiency of transmission of Myzus persicae is nominally set to a REF of 1 and REFs for other species are calculated relative to this. These data represent the first set of REFs calculated for PVA transmission. Macrosiphum euphorbiae (REF 0.91) was almost as efficient as M. persicae at PVA transmission. The data were further analysed to compare transmission rates of PVY and PVA using a binomial (logit) generalized mixed model to take into account the potential influence of variation in virus titre between leaves. This approach found that there is little variation between the efficiency of transmission between clones of each aphid species or between strains within a virus species. This is a first report that Aphis fabae, Metopolophium dirhodum, Sitobion avenae, Acyrthosiphon pisum and Cavariella aegopodii have the ability to vector PVA. This study also represents a first report that C. aegopodii has the ability to vector PVY and confirms the potential of S. avenae, A. fabae, M. euphorbiae and Rhopalosiphum padi as important PVY vectors.     

The yellow rose aphid <Emphasis Type="Italic">Rhodobium porosum</Emphasis>: a new pest of Damask rose in Turkey

Apterous and alate viviparous females of the yellow rose aphid, Rhodobium porosum (Sanderson) (Hemiptera: Aphididae), were collected on Damask rose, Rosa damascena Mill., in Isparta Province, Turkey. The aphid is recorded for the first time from Turkey. Brief information about the invasive yellow rose aphid, including its distribution in Isparta Province and a key to the apterous females of aphid species known to infest Damask rose in Turkey, is provided.     

Entomophthoralean fungi associated with the common nettle aphid (Microlophium carnosum Buckton) and the potential role of nettle patches as reservoirs for the pathogens in landscape

Populations of the common nettle aphid, Microlophium carnosum Buckton, inhabiting nettle patches in an agricultural landscape were surveyed for entomophthoralean infection during 1998, 1999 and 2001. Five pathogenic species were identified from the aphid in the course of the survey. Erynia neoaphidis Remaudière & Hennebert, Neozygites fresenii (Nowakowski) Remaudière & Keller, and Neozygites microlophii Keller affected aphid colonies every year. Two minor pathogens, Entomophthora planchoniana Cornu and Conidiobolus obscurus (Hall & Dunn) Remaudière & Keller, were observed only in 2001.An artificial transmission of the three main fungi was carried out to prove horizontal transmission of infection between the common nettle aphid and different aphid species co-occurring in landscape. N. microlophii, probably monophagous pathogen, did not infect any of the six recipient aphid species in the experiment. Transmissions of E. neoaphidis and N. fresenii conidia were successful with five and four aphid species, respectively. The average mortality of tested aphids after transmission ranged from 0 to 33.33% for E.neoaphidis and from 0 to 15% for N. fresenii.     

Entomophthoralean fungi associated with the common nettle aphid (Microlophium carnosum Buckton) and the potential role of nettle patches as reservoirs for the pathogens in landscape

Populations of the common nettle aphid, Microlophium carnosum Buckton, inhabiting nettle patches in an agricultural landscape were surveyed for entomophthoralean infection during 1998, 1999 and 2001. Five pathogenic species were identified from the aphid in the course of the survey. Erynia neoaphidis Remaudière & Hennebert, Neozygites fresenii (Nowakowski) Remaudière & Keller, and Neozygites microlophii Keller affected aphid colonies every year. Two minor pathogens, Entomophthora planchoniana Cornu and Conidiobolus obscurus (Hall & Dunn) Remaudière & Keller, were observed only in 2001.An artificial transmission of the three main fungi was carried out to prove horizontal transmission of infection between the common nettle aphid and different aphid species co-occurring in landscape. N. microlophii, probably monophagous pathogen, did not infect any of the six recipient aphid species in the experiment. Transmissions of E. neoaphidis and N. fresenii conidia were successful with five and four aphid species, respectively. The average mortality of tested aphids after transmission ranged from 0 to 33.33% for E.neoaphidis and from 0 to 15% for N. fresenii.The potential of nettle patches as natural reservoirs for pathogens in the agroecosystem is discussed.     

Aphidius colemani Vier. (Hymenoptera, Braconidae, Aphidiinae) detected in cereal fields in Germany

Studies conducted in the 2000 cropping season at two different localities, Flaeming and Magdeburger Boerde in Germany, have provided new information on cereal aphid (Sitobion avenae (F.), Metopolophium dirhodum (Walker), and Rhopalosiphum padi (L.)) parasitoids in winter wheat; their species composition, relative abundance, hosts, and location effects. The average aphid population density was higher at Magdeburger Boerde and lower at Flaeming. Among the aphid species, Sitobion avenae was more abundant at Flaeming and Metopolophium dirhodum at Magdeburger Boerde. In total, eight species of primary parasitoids were recorded: Aphidius colemani Viereck, Aphidius rhopalosiphi DeStefani Perez, Aphidius uzbekistanicus Luzhetzki, Aphidius ervi Haliday, Aphidius picipes (Nees), Ephedrus plagiator (Nees), Praon gallicumStarý, and Praon volucre (Haliday). The predominant parasitoid species were Aphidius colemani and Aphidius rhopalosiphi on Metopolophium dirhodum and Aphidius uzbekistanicus on Sitobion avenae. A low number of hyperparasitoids were also recorded. Aphidius colemani was recorded for the first time in the open winter wheat fields in Germany, although it has been used as a biocontrol agent in glasshouses in many European countries and overseas. An analysis of the aforementioned information shows that Aphidius colemani detected as a parasitoid of cereal aphids in Germany is likely a result of an accidental escape of parasitoids from a glasshouse, as well as their successful overwintering and establishment in the area. This study provides baseline information essential for assessing future changes in aphid parasitoid species guild and dynamics in cereal fields in Germany.     

Adaptation of native syrphid flies to new exotic plant (Impatiens spp.)-aphidant associations in Central Europe (Dipt., Syrphidae; Hom., Aphididae; Hym., Formicidae)

Impatiens parviflora andI. glandulifera, two invasive touchme-not species of exotic origin were found to be associated with two aphid groups in Central Europe: a) Exotic species subsequently following their invasive plant hosts (Impatientinum asiaticum Nevsky), b) native species secondarily adapted to the new exotic hosts (Aphis fabae cirsiiacanthoidis Scop.). The species number (listed) of associated syrphid flies in the newly developed guilds was rather high, consisting of broadly oligophagous species. The plant phenology and adaptation of the aphids have resulted in associations which apparently represent seasonally significant sources of prey, their importance apparently increasing with the decreasing season. Antattendance was determined in both aphid species, and no adverse interference with the preying syrphid larvae was observed. In spite of an overall classification of the target plants as expansive weeds, they are classified positively as contributing to the enhancement of syrphid fly populations in the biocorridors in the cultivated landscape.     

Aphidius colemani Vier. (Hymenoptera, Braconidae, Aphidiinae) detected in cereal fields in Germany

Studies conducted in the 2000 cropping season at two different localities, Flaeming and Magdeburger Boerde in Germany, have provided new information on cereal aphid (Sitobion avenae (F.), Metopolophium dirhodum (Walker), and Rhopalosiphum padi (L.)) parasitoids in winter wheat; their species composition, relative abundance, hosts, and location effects. The average aphid population density was higher at Magdeburger Boerde and lower at Flaeming. Among the aphid species, Sitobion avenae was more abundant at Flaeming and Metopolophium dirhodum at Magdeburger Boerde. In total, eight species of primary parasitoids were recorded: Aphidius colemani Viereck, Aphidius rhopalosiphi DeStefani Perez, Aphidius uzbekistanicus Luzhetzki, Aphidius ervi Haliday, Aphidius picipes (Nees), Ephedrus plagiator (Nees), Praon gallicumStarý, and Praon volucre (Haliday). The predominant parasitoid species were Aphidius colemani and Aphidius rhopalosiphi on Metopolophium dirhodum and Aphidius uzbekistanicus on Sitobion avenae. A low number of hyperparasitoids were also recorded. Aphidius colemani was recorded for the first time in the open winter wheat fields in Germany, although it has been used as a biocontrol agent in glasshouses in many European countries and overseas. An analysis of the aforementioned information shows that Aphidius colemani detected as a parasitoid of cereal aphids in Germany is likely a result of an accidental escape of parasitoids from a glasshouse, as well as their successful overwintering and establishment in the area. This study provides baseline information essential for assessing future changes in aphid parasitoid species guild and dynamics in cereal fields in Germany.     

Report on the palm aphid, <Emphasis Type="Italic">Cerataphis brasiliensis</Emphasis> on ‘Kalparaksha’ coconut cultivar

Aggregations of palm aphid Cerataphis brasiliensis (Hempel) (Aphididae: Hemiptera) on the unfurled spindle leaf of ‘Kalparaksha’ variety of coconut, a selection from Malayan Green Dwarf, is reported for the first time. C. brasiliensis has not yet been observed from other coconut varieties, viz., West Coast Tall, Chowghat Orange Dwarf, Chowghat Green Dwarf, and Dwarf x Tall hybrids planted in the research farm of Central Plantation Crops Research Institute, Kayangulam, Kerala, India. Only the apterous form of the palm aphid was noticed in the semi-tall variety and a variety-induced emergence of C. brasiliensis is indicated under natural conditions. Due to the presence of two phoretic ant species, no natural predator was observed in the aphid colonies. Two sprays of dimethoate (0.05%) at an interval of 15–20 days were effective in suppression of the pest on Kalparaksha.     

Spring aphid-parasitoid (Hom., Aphididae, Hym., Braconidae) associations and interactions in a Mediterranean arable crop ecosystem, including Bt maize

Conspecific and heterospecific associations of aphid parasitoids (Hymenoptera, Braconidae, Aphidiinae) were used to determine the interactions between crops forming the main arable crop ecosystem (wheat, alfalfa, isogenic and [Bt Bacillus thuringiensis] transgenic maize) in an irrigated area in Catalonia, Spain. Species composition and instars of parasitized aphids (mummies) were used to detect the parasitoid population movements between the crops and proved interactions (alternation) between the crops, including transgenic maize. Parasitoid interactions were species-dependent, appearing in the movements between alfalfa-wheat-maize in the individual species. Aphidius ervi Hal., A. rhopalosiphi DeSt.-Perez, A. uzbekistanicus Luzh., Lysiphlebus testaceipes (Cress.) and Praon volucre (Hal.) were classified as key-stone species in the target agroecosystems in the area. No differences were found in aphid-parasitoid associations on Bt transgenic maize and isogenic maize for aphid species composition and associated parasitoid guild.     

宁夏中宁县麦蚜寄生蜂群落多样性及优势种种群动态

为了解西北干旱区麦田蚜虫寄生蜂的多样性及优势种的种群动态,采用棋盘式五点取样法对宁夏中宁县麦蚜寄生蜂群落组成进行调查与研究,分析其多样性、丰富度、均匀度及优势度指数等指标的变化,应用Gaussian函数对各指标进行拟合,并对寄生蜂优势种的个体发生量进行时间动态描述。结果显示,该地区共调查获得麦蚜寄生蜂标本919份,隶属4总科7科12属21种,其中初寄生蜂11种,重寄生蜂10种。燕麦蚜茧蜂Aphidius avenae为初寄生蜂优势种,6月2日个体数达到顶峰,6月8日骤降,6月23日趋于平缓;重寄生蜂优势种为蚜虫宽缘金小蜂Pachyneuron aphidis、宽肩阿莎金小蜂Asaphes suspensus和蚜茧蜂长背瘿蜂Alloxysta sp.,前二者个体数均在6月18日达到最大值,6月23日呈下降趋势,后者5月28日上升,6月2日达到顶峰,6月23日缓慢降至最低值。该地区5月初麦蚜初寄生蜂的多样性指数较大,重寄生蜂的多样性指数则在5月中旬开始上升,总群落多样性指数在6月上旬最高;Gaussian函数对寄生蜂群落多样性指数时间动态变化的模型拟合参数表明,复杂农业景观下的寄生蜂物种多样性发生期明显长于简单农业景观。     

Aphid transmissibility of different European beet polerovirus isolates

Different field isolates of the ‘beet poleroviruses’ Beet mild yellowing virus (BMYV) and Beet chlorosis virus (BChV) (genus Polerovirus, family Luteoviridae) collected in France and Poland were evaluated for transmissibility from and to sugar beet plants by different aphid species. In general, both BMYV and BChV were efficiently transmitted by Myzus persicae and by a French clone of Macrosiphum euphorbiae. In contrast, transmissibility of the two poleroviruses by an English clone of M. euphorbiae was evidently weaker, although the aphid samples contained the virus as demonstrated by RT-PCR. None of the BMYV or BChV isolates was transmitted by Aphis fabae or Myzus ascalonicus. In attempting to correlate biological properties with molecular variations, the RT proteins were sequenced. Some amino acid point variations, presumably affecting aphid transmissibility, were identified.     

Detection and Indentification of European Stone Fruit Yellows and Other Phytoplasmas in Wild Plants in the Surroundings of Apricot Chlorotic Leaf Roll-affected Orchards in Southern France

Between 1994 and 1998 a field study was conducted to identify plant hosts of the European stone fruit yellows (ESFY) phytoplasma in two apricot growing regions in southern and southwestern France where the incidence of apricot chlorotic leaf roll was high. A total of 431 samples from 51 different plant species were tested for the presence of phytoplasmas by PCR using universal and ESFY-specific primers. ESFY phytoplasma was detected in six different wild growing Prunus species exhibiting typical ESFY symptoms as well as in symptomless dog rose bushes (Rosa canina), ash trees (Fraxinus excelsior) and a declining hackberry (Celtis australis). The possible role of these plant species in the spread of ESFY phytoplasma is discussed. PCR-RFLP analysis of ribosomal DNA amplified with the universal primers was carried out to characterize the other phytoplasmas found. Thus, elm yellows phytoplasma, alder yellows phytoplasma and rubus stunt phytoplasma were detected in declining European field elm trees (Ulmus carpinifolia Gled), in declining European alder trees (Alnus glutinosa) and in proliferating Rubus spp. respectively. The presence of rubus stunt phytoplasma in great mallow (Malva sylvestris) and dog rose was demonstrated for the first time. Furthermore, the stolbur phytoplasma was detected in proliferating field bindweed (Convolvulus arvensis) and a previously undescribed phytoplasma type was detected in red dogwood (Cornus sanguinea). According to the 16S rDNA-RFLP pattern this new phytoplasma belongs to the stolbur phytoplasmas group.     

Comparison ofPotato Virus Y andPlum Pox Virus transmission by two aphid species in relation to their probing behavior

Two different aphid species,Myzus persicae (Sulzer) andHyalopterus pruni (Geoffroy) (Homoptera: Aphididae), were used to analyze their ability to transmit two different potyviruses,Potato virus Y (PVY) andPlum pox virus (PPV), to pepper (Capsicum annuum) andNicotiana benthamiana plants, respectively. In parallel experiments,M. persicae consistently transmitted both viruses with high efficiency, whereasH. pruni always failed to transmit either virus. This is in contrast to previous reports describingH. pruni as a vector of these potyviruses. Different aphid probing behavior among individual aphids of each species was obtained in electrical penetration graph (EPG) experiments performed on pepper plants. This suggested thatH. pruni did not transmit these potyviruses due to behavioral differences during probing that impeded virus acquisition and/or inoculation. It was found thatM. persicae usually makes its first probe within the first 2 min, whereasH. pruni individuals remained for more than 10 min on the plant before starting to probe. Furthermore,M. persicae individuals displayed their first intracellular puncture during the first minute of probing whereasH. pruni needed ∼ 15 min to penetrate the cell plasmalemma with their stylets. In addition, intracellular stylet punctures occurred very frequently forM. persicae but was a rare event, never exceeding a single one, forH. pruni. The relevance of these findings for the epidemiological spread of potyviruses by different aphid species is discussed. http://www.phytoparasitica.org posting May 14, 2006.