Feeding and egg distribution studies of Heringia calcarata (Diptera: Syrphidae), a specialized predator of woolly apple aphid (Homoptera: Eriosomatidae) in Virginia apple orchards

Predation by the aphidophagous syrphid fly Heringia calcarata (Loew) on woolly apple aphid, Eriosoma lanigerum (Hausmann), was studied in the laboratory and in Virginia apple orchards. Feeding studies compared the prey suitability of three temporally sympatric aphid pests of apple: spirea aphid, Aphis spiraecola Patch; rosy apple aphid, Dysaphis plantaginea (Passerini); and woolly apple aphid. Significantly more H. calcarata larvae survived and completed development on a pure diet of woolly apple aphid than on rosy apple aphid, and none survived on spirea aphid. Final larval weights were significantly greater, and the larval developmental period was significantly shorter on woolly apple aphid than on rosy apple aphid, but neither the duration of pupal development nor adult weight differed between diets. H. calcarata larvae consumed an average of 105 woolly apple aphids during their development. Na?ve, neonate larvae given access to all possible pair combinations of woolly apple aphid, rosy apple aphid, and spirea aphid consumed significantly more woolly apple aphids in all pairings that included woolly apple aphid. When given a choice of rosy apple aphid and spirea aphid, significantly more rosy apple aphids were consumed. Weekly counts of syrphid eggs found in woolly apple aphid, rosy apple aphid, and spirea aphid colonies collected from apple trees showed that two generalist hover fly predators, Eupeodes americanus (Wiedemann) and Syrphus rectus Osten Sacken, were present in colonies of all three aphid species and that E. americanus was the most abundant syrphid predator in A. spiraecola and D. plantaginea colonies. H. calcarata eggs were found only in woolly apple aphid colonies and were more abundant there than E. americanus and S. rectus. These data suggest that H. calcarata is a specialized predator of woolly apple aphid in the apple ecosystem in Virginia.     

Population dynamics of Cacopsylla melanoneura (Homoptera: Psyllidae), a vector of apple proliferation phytoplasma in northwestern Italy

Apple proliferation is a phytoplasma-associated disease transmitted by insects causing serious damage and economic losses to apple orchards. Investigations were carried out in 1999 and 2000 in northwestern Italy to identify the vector of apple proliferation and to study its population dynamics. Yellow sticky traps and beat tray samples revealed the presence of the psyllid Cacopsylla melanoneura (Forster) in eight apple orchards in the Aosta Valley. The species completes one generation per year; the overwintered psyllids colonized apple trees beginning in late January, whereas the springtime generation was observed beginning in early May. The offspring adults remained in apple orchards until the end of June, when they began to move onto other hosts. During 1999 and 2000, all apple trees present in the investigated orchards were visually checked to assess the fluctuation of disease symptoms. Polymerase chain reaction and restriction fragment-length polymorphism confirmed the presence of the apple proliferation phytoplasmas in both overwintering and offspring insects as well as in symptomatic apple plants. The ability of C. melanoneura to vector the disease was assessed by preliminary transmission trials. Overwintered psyllids, collected in the most affected orchards, caged on healthy apple test plants transmitted apple proliferation phytoplasmas.     

Cloning and characterization of a cyclic peptide synthetase gene from Alternaria alternata apple pathotype whose product is involved in AM-toxin synthesis and pathogenicity

Afternaria afternata apple pathotype causes Alternaria blotch of susceptible apple cultivars through the production of a cyclic peptide host-specific toxin, AM-toxin. PCR (polymerase chain reaction), with primers designed to conserved domains of peptide synthetase genes, amplified several products from A. alternata apple pathotype that showed high similarity to other fungal peptide synthetases and were specific to the apple pathotype. Screening of a Lambda Zap genomic library with these PCR-generated probes identified overlapping clones containing a complete cyclic peptide synthetase gene of 13.1 kb in length with no introns. Disruption of this gene, designated AM-toxin synthetase (AMT), by transformation of wild-type A. afternata apple pathotype with disruption vectors resulted in toxin-minus mutants, which were also unable to cause disease symptoms on susceptible apple cultivars. AM-toxin synthetase is therefore a primary determinant of virulence and specificity in the A. alternata apple pathotype/apple interaction.     

苹果对硒的吸收及其积聚特征研究

对秦冠苹果采用不同浓度的硒溶液进行了花期喷施、对干注射和土壤施加３种处理,研究了苹果树对硒的吸收,找到了生产富硒苹果的有效方法。研究表明,硒并不是苹果必需的微显元素;首次提出了苹果树属非积聚硒植物的新概念;同时也对食用富硒苹果的有效性与安全性进行了分析     

Dimers of beta 2-glycoprotein I mimic the in vitro effects of beta 2-glycoprotein I-anti-beta 2-glycoprotein I antibody complexes

Anti-beta(2)-glycoprotein I antibodies are thought to cause lupus anticoagulant activity by forming bivalent complexes with beta(2)-glycoprotein I (beta(2)GPI). To test this hypothesis, chimeric fusion proteins were constructed of the dimerization domain (apple 4) of factor XI and beta(2)GPI. Both a covalent (apple 4-beta(2)GPI) and a noncovalent (apple 4-C321S-beta(2)GPI) chimer were constructed. As controls, apple 2-beta(2)GPI and apple 4-C321S-beta(2)GPI-W316S, in which beta(2)GPI-W316S is not able to bind to phospholipids, were made. In a phospholipid binding assay, apple 4-beta(2)GPI and apple 4-C321S-beta(2)GPI were able to bind to phospholipids with an affinity 35 times higher than that of plasma-derived beta(2)GPI and apple 2-beta(2)GPI. Apple 4-C321S-beta(2)GPI-W316S did not bind at all. Only apple 4-beta(2)GPI and apple 4-C321S-beta(2)GPI were able to bind to adhered platelets as shown by immunofluorescence. Using the prothrombin time, which was the most responsive coagulation assay, the clotting time was approximately doubled when 200 microg/ml apple 4-beta(2)GPI or apple 4-C321S-beta(2)GPI was added. Addition of 200 microg/ml plasma-derived beta(2)GPI, apple 2-beta(2)GPI, or apple 4-C321S-beta(2)GPI-W316S did not affect clotting time. Clotting time could be corrected with the addition of extra phospholipids, which is indicative for lupus anticoagulant activity. An additional increase in clotting times for apple 4-beta(2)GPI or apple 4-C321S-beta(2)GPI was achieved by the addition of monoclonal antibodies against beta(2)GPI. In conclusion, dimerization of beta(2)GPI explains the in vitro observed effects of beta(2)GPI-anti-beta(2)GPI antibody complexes.     

苹果炭疽叶枯病菌致病力分析及苹果种质抗病性鉴定

苹果炭疽叶枯病是由胶孢炭疽菌(Colletotrichum gloeosporioides)引起的一种真菌病害,现已上升为世界苹果生产中的主要病害之一。了解不同来源的苹果炭疽叶枯病菌致病力差异及明确苹果种质资源对苹果炭疽叶枯病的抗性,对品种选育、品种合理布局以及控制病害的流行具有重要的参考价值。本研究对不同来源的79株病原菌进行了室内致病力测定,获知该菌致病力差异明显,其中强致病力菌株所占比例大。同时,本研究也对327份苹果种质资源进行了室内抗病性鉴定,其中高抗资源160份,中抗资源6份,中感资源22份,高感资源139份。表明我国现保存的苹果种质资源中存在丰富抗病种质。进一步按苹果分类系统分析发现,抗病资源在当前栽培的主要品种群中均有分布,特别是红玉品种群、富士品种群抗病资源最为丰富。     

Lipid profile of cultured cells of apple (Malus sylvestris) and apple tissue

The potentiality of apple cell cultures to synthesize not only higher quantities of lipids than apple fruit but also different classes of lipids is noted. Total lipid was 15-fold higher in apple callus than in the original tissue. On callusing, linoleic acid decreased from 66% to 14%, while linolenic acid showed a very large increase from 0.9% to 44%. Stearic and oleic acids also increased in callus. The relative amounts of sterol/hydrocarbon and diglyceride fractions were higher in callus cultures, while apple tissue showed higher levels of triglycerides and sterol. Phosphatidylethanolamine and phosphatidylglycerol seemed to be newly synthesized during callusing while other phospholipids such as lysophosphatidylcholine, lysophosphatidylethanolamine, phosphatidylinositol and phosphatidic acid decreased. There was much higher glycolipid in apple callus than in the original tissue. The ratio of neutral lipid to polar lipid was higher in apple than in apple callus.     

Development of multiplex RT-PCR assay for simultaneous detection of four viruses infecting apple (Malus domestica)

The major viruses infecting apple cultivars throughout the world including India are apple mosaic virus (ApMV), apple stem pitting virus (ASPV), apple stem grooving virus (ASGV), apple chlorotic leaf spot virus (ACLSV), and recently, a new virus, apple necrotic mosaic virus (ApNMV), was reported from mosaic-infected apple cultivars in India. The aim of this study was to detect the ApNMV virus along with the other three viruses (ApMV, ASPV and ASGV) simultaneously by multiplex RT-PCR. Four primer-pair-produced amplicons of 670, 550, 350 and 210 bp corresponding to ApNMV, ApMV, ASPV and ASGV, respectively, were found to be specific for these viruses when tested individually. The annealing temperature (55°C), primer concentration (0·8 µl) and other components of the master mix were standardized for the development of one-step m-RT-PCR assay. The m-RT-PCR protocol developed was further validated with 30 samples from seven symptomatic or asymptomatic apple cultivars, which revealed the presence of more than one virus in these cultivars. Most of the viruses were found to be present either alone or in mixed infection; however, ASPV was more common in tested cultivars. An easy, cost-effective and rapid multiplex RT-RCR protocol was developed to detect the four viruses, which infect apple plants either in individually or together in the field. This assay will help in the surveying and indexing of apple germplasm and the distribution of all four viruses in the apple growing regions of India.     

Beobachtungen über das Befalls-“decline„-Phänomen beim Auftreten von Fußkrankheiten in Monokulturen

In comparative experiments for detecting apple chlorotic leaf spot virus (ApCLSV) in apple cultivars and wild apple varieties using graft indexing the procedure of applying the woody indicator clone Malus pumila MILL. Comparing R 12740 7A and the DAS‐ELISA technique, the reliability of the ELISA in ApCLSV detection in fruit‐bearing cultivars proved to be slightly better than that of R 12740 7A. In certain taxa of wild apple varieties, however, the reliability of the graft indexing procedure in detecting ApCLSV proved to be much better than that of ELISA. The investigation was carried out with 864 trees belonging to 16 apple cultivars and 24 wild apple varieties, respectively.     

黄土高原苹果园土壤水分及水分生产力模拟

以长武地区为例,采用WinEPIC模型模拟1980—2018年间黄土高原旱作苹果园地深剖面土壤水分和水分生产力变化动态,以期为该区苹果产业的可持续发展提供科学依据。结果表明: 长武地区苹果园年均产量为26.37 t·hm^-2,年均蒸散量为673.66 mm,年均水分生产力为4.07 kg·m^-3,成龄果树水分胁迫天数主要受降雨量影响,果树生长后期年均胁迫天数为46.46 d,深层土壤含水量最早于9龄果树开始接近凋萎湿度。长武地区苹果整个生长周期内供水量是对果园产量影响最大的因素,深层土壤有效水含量降低是制约果树生长中后期产量提高的最主要因素,在降水不足的年份果树会利用更深层土壤水分。当深层土壤可利用水分较少时,过多的降水并未被果树利用,而是转化为浅层土壤水分蒸发。对于成龄果树在年供水量低于500 mm或高于700 mm时都会造成产量的下降。针对不同生长时期的果园,在不同的降雨年份应该调整果园水分管理策略,可以通过补充灌溉、拦蓄集聚雨水、覆盖、修剪枝条等管理措施,降低果树非生产性耗水及自身奢侈性耗水,延缓深层土壤干层的出现时间,在保证果树生长的同时避免水资源的浪费。     

安徽苹果生态区划的模糊聚类分析

本文根据苹果对生态条件的要求,选择了影响苹果生长发育的四个重要气象因子,采用模糊聚类方法,对安徽省栽培苹果的生态气候条件进行研究,初步划出了安徽苹果经济栽培的南线．作者认为,宿县、泗县以北地区是乔化苹果栽培的次适宜区,阜阳、寿县和定远一线为矮化苹果栽培的南线．     

壳聚糖涂膜对机械伤苹果抗性生理特征的影响

为了提高苹果采后抗机械损伤能力,减少贮藏损失,以红富士苹果为材料,通过人工模拟机械伤试验,研究壳聚糖涂膜对损伤红富士苹果常温贮藏条件下果肉褐变、相关酶活性及抗性相关物质的影响,探索壳聚糖涂膜在果蔬防腐保鲜上的应用。结果显示:壳聚糖涂膜处理科显著减少红富士苹果果实机械伤口的扩张,提高机械伤果实的总酚含量,降低PPO活性,从而有效抑制机械伤苹果贮藏期间的果肉褐变的发生。同时,壳聚糖涂膜处理可提高机械伤苹果的POD和PAL活性,延缓酚类物质含量的下降,促进体内木质素的合成。研究表明,壳聚糖涂膜处理能够有效防止机械伤苹果贮藏期间的酶促褐变,减少果肉组织中有害物质的积累,促进愈伤组织的形成,从而增强了机械伤苹果的抗性,有效延缓了果实衰老。     

Rainfastness of a microencapsulated sex pheromone formulation for codling moth (Lepidoptera: Tortricidae)

The rainfastness of a microencapsulated sex pheromone formulation for codling moth, Cydia pomonella (L.), was evaluated in a series of laboratory experiments with detached apple, pear, and walnut leaves. Increasing the intensity and duration of simulated rainfall significantly increased the removal of microcapsules from both the top and bottom of apple leaves. The removal of microcapsules was significantly higher from the top versus the bottom of leaves at all rates tested. Leaf angle was a significant factor affecting the removal of microcapsules from the top surface of apple leaves with fewer microcapsules removed, because leaves were oriented with a steeper downward angle. Both leaf surfaces of apple and pear retained a higher proportion of microcapsules than walnut leaves, and the bottom surface of apple leaves retained significantly more than pear leaves. Three spray adjuvants were evaluated as stickers for microcapsules. No difference was found in the number of microcapsules deposited on apple leaves among three stickers tested at rates from 0.06 to 0.25%. However, in a second test a latex sticker significantly increased the deposition of microcapsules on apple leaves compared with a polyvinyl polymer and a pine resin sticker at a rate of 0.06%. Significantly more microcapsules were retained on the bottom versus the top of apple leaves with all stickers. The latex and polyvinyl stickers significantly increased the retention of microcapsules versus the pine resin sticker and the control on apple leaves. In another test, the addition of 0.06% latex sticker did not increase the deposition of microcapsules on any of the three leaf types. However, the addition of the latex sticker significantly increased the retention of microcapsules on the top of apple and pear leaves and the bottom of apple leaves. The addition of a latex sticker did not affect the retention of microcapsules on walnut leaves.     

The effect of carbamide and thiocarbamide on the resistance of apple to apple scab

Carbamide and thiocarbamide decreased the resistance of apple to apple scab when infiltrated into apple leaves prior to infection with the disease. In three apple varieties these two substances strikingly stimulated infection with two monosporic isolates of the fungusVenturia inaequalis (Cke.) Wint. It was established that both carbamide and thiocarbamide inhibited polyphenol oxidase activity in apple leavesin vivo, butin vitro only thiocarbamide was inhibitory. It can be concluded that the effect on apple resistance to apple scab is based on an inhibition of polyphenol oxidase.     

环渤海湾苹果产区老果园与连作果园土壤线虫群落特征

应用类群多样性、类群丰富度、个体密度和功能类群指数等群落参数,于2009年5-10月分3次对环渤海湾苹果栽植区老果园不同位置和连作果园取样研究了土壤线虫群落特征。结果表明:苹果连作对果园土壤生物环境具有明显的恶化作用,连作果园土壤环境条件恶劣;对功能类群指数的统计表明,苹果连作明显改变了果园土壤中植物寄生性线虫r-选择和k-选择的比例,与自由生活线虫比较,连作对植物寄生线虫影响更明显;连作提高了果园的土壤线虫PPI/MI,说明连作对果园土壤健康的扰动最大;土壤不同食性线虫数量统计结果显示,环渤海湾苹果栽植区植食性线虫数量未达线虫伤害阈值,线虫不是引起环渤海湾地区苹果连作障碍的主要原因。     

Rhizosphere micro-organisms in relation to the apple replant problem

Summary One of the factors giving rise to soil sickness in apple orchards is the rhizosphere microflora. The composition of the microbial coenosis in the rhizosphere changes with increasing age of the apple trees. An increase in the counts of micromycetes and actinomycetes and a decrease in bacterial counts was found in agreement with the decreasing pH of the rhizosphere soil. The presence of fluorescent pseudomonads in the rhizosphere of old apple trees was rare, but the planting of apple seedling into sick soil induced their proliferation. The relative proportion of individual genera of micromycetes changed according to the tree age; fungi of the genus Mucor were more often found in the rhizosphere of younger trees than in that of older ones while fungi of the genus Penicillium had an opposite trend. Biological tests showed that Penicillium fungi form the majority of the phytotoxic microflora. The amount of phytotoxic micromycetes was higher in ‘sick’ soil as compared with control soil in which apple trees had not been grown for at least 15 years. Higher numbers of phytotoxic micromycetes were isolated also from the rhizosphere of apple seedlings grown in ‘sick’ soil as compared with those growing in control soil. An increase in the amount of phytotoxic micromycetes in apple tree rhizosphere could be induced by mere addition of 5% (w/w) ‘sick’ soil to the soil in which apple trees were grown for the first time. By adding sterilized ‘sick’ soil, the amount of phytotoxic micromycetes in the apple seedling rhizosphere was not affected. Increased numbers of phytotoxic micromycetes affected negatively the growth of apple trees and the morphology of apple tree roots. This demonstrated the possibility of transfer of a factor participating in the etiology of soil sickness in apple orchards.     

渭北旱塬苹果园地产量和深层土壤水分效应模拟

为了研究实时气象条件下渭北旱塬不同生长年限苹果园地产量变化趋势和深层土壤水分变化规律,在模型适用性与模拟精度验证基础上,应用WinEPIC模型模拟研究了1962—2001年期间洛川旱塬苹果园地产量演变动态和深层土壤水分效应。结果表明：(1) 在模拟研究期间,洛川旱塬4—40年生苹果园产量整体上呈波动性下降趋势,初期产量逐渐增加,11—23年生达到最大值(平均为28.8 t/hm2),之后随降水量年际波动呈现出明显的波动性降低趋势。(2) 40年间苹果园地遭受的干旱胁迫日数呈波动性上升趋势,与年降水量波动趋势相反。(3) 1—15年生期间苹果园地平均年耗水量高于同期年降水量,导致苹果园地0—10 m土层土壤强烈干燥化,逐月土壤有效含水量波动性降低,1—10年生、11—20年生和21—40年生期间发生土壤干燥化并且程度逐渐加剧,但干燥化速率逐渐减缓,土壤干燥化速率分别为95.4 mm/a、12 mm/a和1.5 mm/a。(4) 随生长年限的延长,苹果园地0—10 m土层土壤湿度逐渐降低、土壤干层分布深度逐渐加大,在14年生时超过了10 m,20年生以后2—10 m 土层形成稳定的土壤干层。因此,基于土壤水分利用的苹果生长与果园利用的合理年限为20 a,最长不宜超过23 a。     

中国苹果病害病原菌物名录

苹果为我国主要栽培水果,苹果产业在我国农业生产中占有重要地位.病原菌物是苹果病害的主要病原物,对我国苹果产量和品质造成严重损害.国际上病原菌物为苹果主要病原类型,其数量占苹果病原物的93.4％.我国植物病理学家和菌物学家对苹果病害的病原学进行了长期研究,描述与记载了大量国外已报道的病原真菌和病原卵菌,也描述了一些国外尚...     

Microsatellite markers spanning the apple (Malus x domestica Borkh.) genome

A new set of 148 apple microsatellite markers has been developed and mapped on the apple reference linkage map Fiesta x Discovery. One-hundred and seventeen markers were developed from genomic libraries enriched with the repeats GA, GT, AAG, AAC and ATC; 31 were developed from EST sequences. Markers derived from sequences containing dinucleotide repeats were generally more polymorphic than sequences containing trinucleotide repeats. Additional eight SSRs from published apple, pear, and Sorbus torminalis SSRs, whose position on the apple genome was unknown, have also been mapped. The transferability of SSRs across Maloideae species resulted in being efficient with 41% of the markers successfully transferred. For all 156 SSRs, the primer sequences, repeat type, map position, and quality of the amplification products are reported. Also presented are allele sizes, ranges, and number of SSRs found in a set of nine cultivars. All this information and those of the previous CH-SSR series can be searched at the apple SSR database () to which updates and comments can be added. A large number of apple ESTs containing SSR repeats are available and should be used for the development of new apple SSRs. The apple SSR database is also meant to become an international platform for coordinating this effort. The increased coverage of the apple genome with SSRs allowed the selection of a set of 86 reliable, highly polymorphic, and overall the apple genome well-scattered SSRs. These SSRs cover about 85% of the genome with an average distance of one marker per 15 cM.E. Silfverberg-Dilworth and C. L. Matasci contributed equally to this work.