Detection and partial molecular characterization of Plum pox virus on almond trees in Turkey

Almond (Prunus dulcis) is one of the well known stone fruit species grown for its unripe fruits and delicious seeds in Turkey. In the Trakya region, however, some prevailing virus infections have reduced almond yields and quality. In ten districts of Trakya, 260 leaf samples were collected from affected almond trees in June 2010. DAS–ELISA assays and RT-PCR tests were employed for the identification of viruses. As a result of these detection studies, five of the 260 leaf samples gathered from symptomatic almond trees had Plum pox virus (PPV), 81 of them had Prunus necrotic ringspot virus (PNRSV), and 11 samples contained Prune dwarf virus (PDV). Only four out of 260 samples had a mixture of these viruses. Partial nucleotide sequences of five almond isolates of PPV were determined and compared with 17 other PPV isolates in databases. Computer analysis of obtained and published nucleotide sequences showed identity ranged from 75.72% to 96.87%. Of the five PPV almond isolates obtained, however, there was a close nucleotide identity of 95.82–96.61% to Turkish isolates. Phylogenetic analysis of nucleotides and amino acids showed that five PPV isolates of almond from the Trakya Region of Turkey were clustered in the same subgroup with PPV-T Turkish isolates in GenBank. Therefore we can consider almond isolates of PPV as PPV-T strain, like the two other isolates from apricot trees in Turkey.     

Detection of Apricot latent virus and Plum bark necrosis stem pitting-associated virus by RT-PCR in Eastern Anatolia (Turkey)

Field surveys were carried out to determine presence and incidence of Apricot latent virus (ApLV) and Plum bark necrosis stem pitting-associated virus (PBNSPaV) in the main stone fruit growing areas of Eastern Anatolia. RT-PCR and nested-RT-PCR techniques were used to detect ApLV and PBNSPaV, respectively. Three apricot samples out of 224 tested positive for ApLV, although infected trees showed no apparent disease symptoms. Of 45 sweet cherry and plum trees tested for PBNSPaV, 35 tested positive. Stem pitting symptoms were observed on the trunks of PBNSPaV-infected sweet cherries. Trunk bark was spongy and thick; pits and grooves were observed on the woody cylinder. The overall incidence of ApLV was 1.3% and of PBNSPaV was 77%. This is the first report of ApLV and PBNSPaV in Eastern Anatolia, Turkey.     

Sanitary status of stone-fruit trees in East Anatolia (Turkey) with particular reference to apricot

Field surveys were carried out in the main stone-fruit-growing areas of East Anatolia (Turkey) to assess the sanitary status of varietal collections, mother blocks and commercial orchards. The presence of virus and virus-like diseases was ascertained by enzyme-linked immunosorbent assay (ELISA), sap transmission to herbaceous hosts, graft transmission to peach cv. GF305 and molecular hybridization tests. A total of 1019 samples was tested by ELISA (859 apricot, 120 cherry, 21 almond and 19 peach). The sanitary status of apricot was extremely satisfactory, as the infection level was less than 0.3%. Cherry and almond, however, showed 21% and 33% infection respectively. The viruses identified were apple chlorotic leaf spot trichovirus (ACLSV), prune dwarf ilarvirus (PDV) and prunus necrotic ringspot ilarvirus (PNRSV). The commonest virus was PDV. Plum pox potyvirus (PPV), apple mosaic ilarvirus (ApMV) and the nepoviruses tomato black ring (TBRV), raspberry ringspot (RpRSV), strawberry latent ringspot (SLRV), cherry leaf roll (CLRV), arabis mosaic (ArMV) and tomato ringspot (ToRSV) were not encountered. Peach latent mosaic viroid (PLMVd) and hop stunt viroid (HSVd) were not detected either.     

Sanitary status of grapevines in south-eastern and central Anatolia (Turkey)

Surveys were carried out in commercial vineyards in the main grapevine-growing areas of south-eastern (Adiyaman, Diyarbakir, Merdin, Sanliurfa, Elazig) and central (Nevşehir) Anatolia (Turkey) to assess the presence and incidence of virus and virus-like diseases. Typical fanleaf symptoms were observed in most of the surveyed areas, but they were particularly frequent in Elazig in cvs Kirmizi, Agin, Sirfoni and Kohnu. Leafroll symptoms were present in most vineyards in Adiyaman, Sanliurfa and Elazig, primarily in the red-fruited cvs Antep Karasi, Humusi, Kohnu and Siyah Kabarcik, and in Nevşheir. Rugose wood symptoms were common in Adiyaman, where vineyards were established with grafted planting material, but not in any of the self-rooted Cappadocian cultivars. Phytoplasma-like symptoms were sometimes observed in Elazig and Nevşheir. Biological (sap inoculation to herbaceous plants and graft transmission to woody indicators) and serological (ELISA) assays were used for virus detection and identification. A total of 55.3% of ELISA-tested vines (296 out of 535) were infected by one (11.4%) or more (43.9%) viruses. GVA ¹ was the most widespread virus (42.4%), followed by GLRaV-1 (38.5%), GFLV (10.7%) and GFkV (7.1%). Surprisingly low (2.4%) was the infection rate by GLRaV-3, and even lower (<1%) that of the other viruses tested, i.e. GLRaV-2, GLRaV-6, GVB and ArMV. GLRaV-7 was not detected. The occurrence of vein mosaic and vein necrosis was ascertained by testing on woody indicators. A putative nepovirus was isolated from a single vine of cv. Kizlar Tahtasi, the identification and characterization of which is still under way.     

Viruses infecting almond trees in the region of Valencia (Spain) 1

In the last 10 years, more than a thousand almond trees have been analysed by the DAS-ELISA method in the Valencia region. The most frequent virus infecting unselected almond trees was prune dwarf ilarvirus (PDV) (62%), followed by prunus necrotic ringspot ilarvirus (PNRSV) (36%), apple mosaic ilarvirus (ApMV) (14%) and apple chlorotic leafspot trichovirus (ACLSV) (2%). Infection levels of selected trees were 26% for PDV, 15% for PRSV, 0% for ApMV and 5% for ACLSV.     

关于设置果树病虫测报观察圃的探讨

近年来,果树在农业生产中占有越来越重要的地位。病虫预测预报作为植保工作的前哨,更应该随着种植结构的变化而进行相应调整。烟台作为全国主要苹果产区,从1994年起,开始着手果树病虫的系统预报工作,先后引进金纹细蛾性诱剂、桃小食心虫性诱剂。通过近8a实践,我们体会到设置规范的果树病虫观察圃为当务之急,其将对促进果树病虫测报向规范化、标准化发展起到重要作用。1病虫观察圃浅释通俗地说,病虫观察圃是病虫测报系统调查田,一般2～3块田。田块保持相对稳定,除病虫不需要防治外,田间管理与一般大田一致。根据病虫发生特点,定时间、定方法…     

An SMS based system for surveillance of wheat rust diseases: a pilot initiative in Central Anatolia region in Turkey

Rust diseases (Puccinia spp.), namely stripe, leaf and stem rusts, are among the major diseases of wheat. Their management requires integrated approaches including timely surveillance, speedy communication and rapid response. This surveillance system was developed in order to facilitate participation of extension offices (in provinces/districts) in the survey of wheat rust diseases and sharing of information quickly. The SMS based system was tested as a pilot tool in the Central Anatolia region of Turkey connecting 25 districts in 5 provinces through an SMS network during the rust development period (April–July) in 2013. The observations from 268 fields indicated that leaf rust and stem rust development was insignificant in the districts covered, occurring in only 2.3% and 1.9% of the fields respectively. Stripe rust prevalence was higher occurring in 44.8% of the fields. Of the inspected fields 2.5% had infected plant incidences between 15% and 40% requiring control measures. Using the SMS reports received from the extension officers, the system facilitated daily monitoring of rust development and exchange of observations among the relevant institutions, also sending out alert messages to designated authorities as necessary. The study demonstrated that the system can serve as a rapid surveillance and communication tool to facilitate timely decision making and rapid response to prevent wheat rust epidemics.     

湖北甘薯病毒病的检测与鉴定

2013—2015年采集了湖北黄冈、鄂州、武汉、荆州以及宜昌等5个地区的甘薯病毒病样品,通过双生病毒通用引物PCR扩增、ds RNA技术和序列分析等方法,鉴定了这5个地区甘薯病毒病的病原。结果显示,甘薯羽状斑驳病毒(Sweet potato feathery mottle virus,SPFMV)、甘薯褪绿矮化病毒(Sweet potato chlorotic stunt virus,SPCSV)、黄瓜花叶病毒(Cucumber mosaic virus,CMV)和甘薯卷叶病毒(Sweet potato leaf curl Georgia virus,SPLCGV)等4种病毒被检出。其中,SPFMV SPLCGV这两种病毒在湖北皆为首次报道。     

Serious fungal and bacterial diseases of almond in Greece 1

The main fungal and bacterial diseases of almond in Greece are reviewed, with particular attention to phytophthora collar rot and verticillium wilt.     

Toxicity of systemic neonicotinoid insecticides to avocado thrips in nursery avocado trees

The efficacies of four systemic neonicotinoid insecticides applied to potted avocado trees at manufacturer-recommended rates were assessed against the avocado thrips, Scirtothrips perseae Nakahara. At the time of treatment, fully expanded first-flush young leaves were tagged for identification, and a proportion of these leaves was used in bioassays with second-instar thrips. At 7 weeks post-treatment, a second flush of leaves had fully expanded on the trees, and these leaves were included in additional bioassays comparing avocado thrips mortality on both first- and second-flush leaves. In bioassays with first-flush leaves, imidacloprid (273 mg AI pot(-1)) was the most effective insecticide, providing at least 70% mortality of thrips for 14 weeks. Thiamethoxam (137 mg AI pot(-1)), clothianidin (109 mg AI pot(-1)) and dinotefuran (241 mg AI pot(-1)) provided good control in bioassays that were conducted within 4 weeks of treatment, but thereafter their efficacies were inconsistent. In bioassays with second-flush leaves, imidacloprid provided at least 70% mortality up to 9 weeks after the insecticide application. Thereafter, mortality declined to 30% or lower. Bioassays with second-flush leaves collected from trees treated with thiamethoxam, clothianidin and dinotefuran resulted in unacceptably low thrips mortality. Monitoring of imidacloprid and thiamethoxam residues by ELISA showed that the greater persistence of imidacloprid in both first and second leaf flushes was due to a steadier uptake of this material. Although thiamethoxam residues rose quickly within the first leaf flush, levels had already begun to dissipate by the time the second leaf flush had started to develop.     

Spatial distribution of wind-driven sediment transport rate in a fallow plot in Central Anatolia,Turkey

Wind erosion is a serious land degradation phenomenon in semi-arid parts of Turkey. It is even becoming more critical problem considering the current effects of global warming and climate change in the region. The objectives of this study are to model spatial variation of aeolian sediment transport and to map Sediment Transport Rate (STR) by geostatistics in a fallow plot in the Central Anatolia. STRs for four consecutive wind cases with different vegetation cover rates were determined using the cyclone BEST sediment traps. Plant cover ratio and height changed between 8 and 25% and 3–12?cm throughout the research period, respectively, and soil moistures ranged between 10.9 and 12.7%. The windstorms lasted for 400, 835, 1240, and 50 minutes with the mean wind velocities of 8.6, 7.7, 7.7, and 6.3?m?s^?1, respectively, for cases 1, 2, 3, and 4. The calculated STRs varied between 0.0248?±?0.0170?kg?m^?1?h^?1 and 0.190?±?0.084?kg?m^?1?h^?1. Spatial analysis revealed that the spatial correlations were between 19 and 48?m and different spatial patterns occurred from one case to another. The study results indicated that the amount of transported sediment and its spatial variation were mostly related to velocity and duration of erosive wind in the fallow area of the arid region.     

RT-PCR检测李坏死环斑病毒的研究

为了从植物组织中快速检测李坏死环斑病毒９ＰＮＲＳＶ）,根据该病毒ＲＮＡ３序列设计引物,对感病和健康组织总ＲＮＡ进行ＲＴ－ＰＣＲ,结果从感病组织中扩增出了大约４５０ｂｐ的目的片段,而健康组织中无此扩增带。将此ＰＣＲ产物连接到ｐＧＥＭ－Ｔ－ｅａｓｙ载体也能转化大肠杆菌ＤＨ５５α菌株,得到了含有目的片段的重组子。并采用双脱氧终止法进行序列配美国报道的李坏死环斑病毒ＲＮＡ３序列对应部分核苷酸基本一致,这表     

Evaluation of seedborne bacterial pathogens on common bean cultivars grown in central Anatolia region,Turkey

Bacterial diseases of bean cause economically important losses worldwide. The most important method for managing bacterial diseases on bean is the use of pathogen-free seed. In this study, 198 different dry bean seed samples of six different cultivars including Dermason, Cali, Sira, Battal, Bombay and Seker, were collected from 12 provinces of Central Anatolia Region of Turkey. All were tested to investigate the seedlots as primary inoculum sources of the major bacterial diseases. The data revealed that 22,72 %, 13,63 %, 11,11 %, 1,51 % and 0.5 % of seed samples tested were contaminated with five seedborne bacterial pathogens, Pseudomonas savastanoi pv. phaseolicola (Psp), Pseudomonas syringae pv. syringae (Pss), Xanthomonas axonopodis pv. phaseoli (Xap), X. axonopodis pv. phaseoli var. fuscans (Xapf) and Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff), respectively. All bacterial strains isolated were identified based on morphological, physiological, biochemical, molecular and pathogenicity tests. The results showed that Psp and Pss were found together on cv. Cali; Psp and Xap on cv. Dermason and cv. Sira; and Pss and Xap on cv. Seker, cv. Dermason, and cv. Cali. Therefore, the results in the present study suggested that evaluation and selection of pathogen-free seeds are very important for preventing the spread of pathogens and effective management of seed borne bacterial diseases prevalent in bean growing regions; in addition to implementation of integrated crop production strategies such as crop rotation, sanitation, seed treatment, tolerant/resistant cultivar selection and proper bactericide application.     

Occurrence of yellowing viruses (Beet pseudo-yellows virus, Cucurbit yellow stunting disorder virus and Cucurbit aphid-borne yellows virus) affecting cucurbits in Greece

A survey of the incidence of yellowing viruses in Greek glasshouse (and occasional field) cucumber and melon crops was carried out during 2000–03. In most cases disease incidence ranged from 50 to 80%. Simplex RT-PCR was used for the detection of Beet pseudo-yellows virus (BPYV) and Cucurbit yellow stunting disorder virus (CYSDV), and DAS-ELISA for the detection of Cucurbit aphid-borne yellows virus (CABYV). The results showed that BPYV was the predominant virus in cucumber and melon crops, whereas CYSDV, reported for first time in Greece, was isolated only in three regions of southern Greece: Rhodes, Crete and Arkadia. CABYV was detected only in three cucumber glasshouses in Pella (Macedonia). A simplified triplex RT-PCR method using a simple sample-preparation protocol was developed to allow rapid, sensitive and simultaneous detection of the three viruses. Sequence comparisons of the PCR products of BPYV and CYSDV revealed 98·7 and 100% amino acid identity, respectively, with previously reported sequences. The arable weed species Amaranthus retroflexus , Selosia cristata , Sonchus oleraceus and Sonchus sp. were identified as potential BPYV reservoirs.     

西花蓟马传播病毒病的研究进展

西花蓟马［Frankliniella occidentalis (Pergande)］是一种世界性的重要农业害虫,目前在69个国家和地区已有报道。西花蓟马能以持久性的方式传播番茄斑萎病毒属(Tospovirus)的病毒,所传播病毒造成的经济损失远远大于其本身所造成的损失。因此,许多学者对西花蓟马及其传播的番茄斑萎病毒属病毒进行了大量研究。本文主要综述了近年来西花蓟马传播病毒的种类、番茄斑萎病毒属病毒的结构以及西花蓟马的传毒机制等方面的研究进展。