实时荧光定量PCR(SYBR Green I)检测不同抗枣疯病枣树品种嫁接接穗中的植原体浓度

在枣疯植原体16S r DNA片段内设计并合成引物对DZ16SF-2/DZ16SR-2(扩增190 bp片段),用重组质粒p MD18-DZ16S为模板建立标准曲线,并建立枣疯植原体实时荧光定量PCR(SYBR Green I)检测体系。溶解曲线分析显示:该引物特异性好,该体系对质粒模板的检测灵敏度达102copies/μL。利用该体系对不同月份、不同发病级别的嫁接接种枣树接穗样品进行植原体含量测定。通过对高抗品种‘星光’,中抗品种‘黑腰子枣’、‘嘎嘎枣’和‘葫芦枣’,感病品种‘月光枣’、‘马牙枣’、‘莲蓬子’、‘北流西冬枣’和高感品种‘大红袍枣’嫁接到发病‘冬枣’砧木上所表现出的不同病级、病情指数和病原浓度比较结果发现,表现无症状的样品中植原体的含量在每克鲜重105~106个,发病Ⅰ~Ⅱ级枝条中植原体浓度在106~107个/g,Ⅲ~Ⅳ级发病枝条含量在107~108个/g鲜重,而V级发病枝条达到每克鲜重109个,表明接种发病的接穗症状严重度与其体内植原体浓度积累密切相关。高抗枣疯病‘星光’品种嫁接接穗体内病原浓度明显低于感病品种,而且有较多‘星光’接穗嫁接的发病砧木症状有所减轻,植原体浓度也有所降低。本研究可为探索枣树品种的抗病机制、抗病性鉴定及枣疯病植原体的防治提供参考。     

7个烤烟新品种(系)的抗病性比较

在重庆巫山和彭水,以云烟87和K326为对照品种,对7个烤烟新品种(系)的抗病性进行比较鉴定。结果表明,XD02抗黑胫病,轻微感赤星病,感气候斑点病;XD03轻微感黑胫病和气候斑点病,感赤星病;XD04感黑胫病、气候斑点病和赤星病;CF227轻微感黑胫病、赤星病,易感气候斑点病;CF228轻微感黑胫病和气候斑点病,易感赤星病;CF233轻微感黑胫病,易感气候斑点病、赤星病;CF234抗黑胫病,轻微感气候斑点病,感赤星病。     

不同施药时期对烟草黑胫病的控制效果研究

为寻找有效控制烟草黑胫病发生的最佳用药时期,避免重复多次用药,在烟草生长的3个关键时期,即移栽期、黑胫病发病初期和团棵期,用72%精甲霜·锰锌可湿性粉剂800倍液灌根处理,比较各处理的发病率、病情指数和防效。结果表明,移栽期和发病初期用72%精甲霜·锰锌可湿性粉剂800倍液处理,对黑胫病的防治效果分别为96.34%和96.58%;团棵初期用72%精甲霜·锰锌可湿性粉剂800倍液处理,对黑胫病的防治效果为0。     

4种诱抗剂对烟草病害的诱抗效果及对烟草生长的影响

比较了诱抗剂赤·吲乙·芸薹、壳聚糖、芸薹素内酯、香菇多糖对烟草青枯病、花叶病毒病、黑胫病的诱抗效果及对烟草生长的影响。发现对云烟87喷施上述诱抗剂,均可有效降低3种病害的发生率和病情指数,并促进烟株生长。其中,0.136%赤·吲乙·芸薹可湿性粉剂10 000倍液处理的应用效果较好,对烟草青枯病、花叶病毒病、黑胫病的诱抗效果分别达78.02%、53.48%、61.63%。     

土壤改良剂对烟草成熟期根茎病害发生和农艺性状的影响

在常规施肥条件下,分别以牡蛎粉、蚯蚓粪、碳基肥、缓控肥为土壤改良剂,以不施用土壤改良剂为对照,在重庆黔江区开展小区试验,研究土壤改良剂对烤烟品种云烟87成熟期烟草青枯病、黑胫病、空茎病和花叶病4种病害的防控作用及其烟草农艺性状的影响.结果表明:土壤施用碳基肥对青枯病的相对防效最高,为54.92%,施用牡蛎粉对黑胫病和花叶病的相对防效最高,分别为62.01%和51.28%,施用缓控肥对空茎病的相对防效最高,为74.68%.土壤改良剂处理后大多数的农艺性状与对照无显著性差异.     

烟草黑胫病和根黑腐病生防假单胞杆菌的筛选与鉴定

为获得对烟草黑胫病和根黑腐病具有双重防病效果且能够促进烟草生长的假单胞杆菌，采用稀释涂布法从40份土壤样品中分离出201株细菌，通过平板对峙和含毒介质法，筛选出对烟草黑胫病和烟草根黑腐病病原菌均具有良好拮抗作用的菌株PA2101和PG3402。盆栽促生试验表明，菌株PA2101和PG3402能协调地改善烟草地上部分的生长和烟草根系发育，均在一定程度上增加了烟草的株高、叶面积、株鲜重、根鲜重、叶片数和根长，提高了烟草的根冠比和根活力。盆栽试验结果表明，菌株PA2101对烟草黑胫病和根黑腐病的防效分别为70.11%和62.67%，均高于其对照药剂；菌株PG3402对两种病害的防效分别为60.92%和60.00%，与对照药剂相当。抗性标记菌株的定殖试验结果表明，菌株PA2101和PG3402在接种后第29 d能定殖于烟草根际土壤和根内，在烟草茎和叶内也能长时间存在，表明两菌株能够良好定殖。16S rDNA序列、菌落形态和生理生化性状分析表明，菌株PA2101为铜绿假单胞杆菌Pseudomonasaeruginosa，菌株PG3402为格拉纳达假单胞杆菌Pseudomonas granadensis。综上所述，菌株PA2101和PG3402对烟草具有良好的促生作用，并对烟草黑胫病和根黑腐病有较好的防病效果，是具有生防潜力的菌株。     

荧光假单胞菌拮抗菌株对烟草疫霉的抑菌机制及控病效果

为探讨烟草根际生防细菌对烟草疫霉Phytophthora nicotianae的抑菌机制,从重庆地区连作烟田健康烟株根际土壤分离获得5株荧光假单胞菌Pseudomonas fluorescens拮抗菌株。通过平板对峙及代谢产物抑菌试验筛选对烟草疫霉具有高效拮抗作用的菌株,其中,P-72-10菌株抑菌效果最强,抑菌带半径达13.0 mm,相对抑制率为68.57%,且该菌株代谢产物对烟草疫霉菌丝生长有明显的抑制作用,相对抑制率达25.39%～46.03%;显微观察发现该菌株可引起烟草疫霉菌丝的分支增多,菌丝顶端膨大呈畸形,多数菌丝中间或顶端细胞的细胞壁加厚、原生质浓缩和产生类似厚壁孢子的细胞。在温室盆栽条件下P-72-10菌株对烟草黑胫病也表现出良好的控病效果,对抗病和感病品种的相对防效分别为53.57%和66.37%。     

重大入侵害虫番茄潜叶蛾在4个烟草品种上的适合度评估

本文以新发重大恶性外来入侵物种番茄潜叶蛾Tuta absoluta (Meyrick)为研究对象,明确了其在云南地区4个主栽烟草品种(‘云烟87’‘云烟99’‘K326’和‘红大’)上的适合度,评估了危害风险。研究结果显示,番茄潜叶蛾在4个烟草品种上均能够完成生活史,并且成虫生殖力、后代羽化量、羽化率及雌雄成虫寿命在不同烟草品种间无显著性差异,但后代孵化量和孵化率均差异显著。番茄潜叶蛾在‘云烟99’上孵化量和孵化率(38%)最大,在‘云烟87’上最小(孵化率为15%)。雌雄性番茄潜叶蛾幼虫在不同烟草品种上的幼虫期和成虫前期的发育时间存在显著差异,且性别和品种对幼虫期和成虫前期的影响存在交互效应。此外,本研究还发现番茄潜叶蛾在‘云烟99’上的发育速率最快,雌雄虫完成从卵到成虫的发育分别需要约39 d和35 d;在‘红大’上的发育速率最慢,雌雄虫完成发育分别需要约44 d和38 d。本研究结果明确了番茄潜叶蛾对云南地区4个主栽烟草品种的为害潜力,同时为当地监测和防控该害虫为害提供了数据支持。     

河北省主推番茄品种抗黄化曲叶病鉴定与筛选初报

采用田间自然鉴定方法对河北省42个番茄生产主推品种进行抗番茄黄化曲叶病鉴定。结果表明,‘迪芬尼’、‘74 589’、‘佳西娜’、‘格利’、‘74 587’、‘荷兰6号’、‘Ty204’等7个品种田间表现明显抗番茄黄化曲叶病,发病率分别为0、0、0、1.35%、1.32%、0、1.76%。其余35个品种田间均表现明显感病,发病率最高的品种为‘鲁寿巨粉’,发病率达到99.22%,各品种发病率差异显著。     

烟草品种对烟草花叶病毒病和黄瓜花叶病毒病的抗性鉴定

由烟草普通花叶病毒(TMV)和烟草黄瓜花叶病毒(CMV)引致的烟草病毒病是世界烟草主产区普遍发生且危害严重的侵染性病害,每年给烟叶生产造成了重大的经济损失。本文采用温室苗期接种鉴定的方法,对16份烟草种质进行了TMV和CMV的抗病性鉴定。结果表明:不同的烟草品种对TMV和CMV的抗病性存在较大差异。在供试种质中,对TMV表现免疫的有‘牛耳烟’、‘8301’、‘台烟7号’、‘三生-NN’共4份材料;表现抗病的有‘吉烟5号’、‘双抗70’、‘大护脖香’、‘秦烟95’共4份材料;表现中抗的有‘铁把子’、‘中烟15’、‘秦烟98’、‘中烟98’共4份材料;表现中感的有‘NC89’、‘翠碧1号’、‘云烟97’共3份材料;表现感病的只有‘秦烟97’。对CMV表现中抗的材料有1份,是‘铁把子’;表现中感的有‘秦烟95’、‘三生-NN’、‘8301’、‘牛耳烟’、‘翠碧1号’共5份材料;表现感病的有‘秦烟98’、‘云烟97’、‘中烟98’、‘NC89’、‘大护脖香’、‘双抗70’、‘秦烟97’、‘中烟15’、‘台烟7号’、‘吉烟5号’共10份材料。研究发现,‘铁把子’是兼抗这两种病毒病的材料。本研究明确了我国16个烟草品种资源的抗病性水平,为抗耐病品种的利用与品种合理布局提供科学依据,同时为烟草抗病毒病育种的亲本选择提供抗源信息。     

Hymenopteran Parasitoids on Fruit-infesting Tephritidae (Diptera) in Latin America and the Southern United States: Diversity, Distribution, Taxonomic Status and their use in Fruit Fly Biological Control

We first discuss the diversity of fruit fly (Diptera: Tephritidae) parasitoids (Hymenoptera) of the Neotropics. Even though the emphasis is on Anastrepha parasitoids, we also review all the information available on parasitoids attacking flies in the genera Ceratitis, Rhagoletis, Rhagoletotrypeta, Toxotrypana and Zonosemata. We center our analysis in parasitoid guilds, parasitoid assemblage size and fly host profiles. We also discuss distribution patterns and the taxonomic status of all known Anastrepha parasitoids. We follow by providing a historical overview of biological control of pestiferous tephritids in Latin American and Florida (U.S.A.) and by analyzing the success or failure of classical and augmentative biological control programs implemented to date in these regions. We also discuss the lack of success of introductions of exotic fruit fly parasitoids in various Latin American countries. We finish by discussing the most pressing needs related to fruit fly biological control (classical, augmentative, and conservation modalities) in areas of the Neotropics where fruit fly populations severely restrict the development of commercial fruit growing. We also address the need for much more intensive research on the bioecology of native fruit fly parasitoids.     

Brief Guide for Authors

正Journal of Arid Land(JAL)is an international journal(ISSN 1674-6767;CN 65-1278/K)for the natural sciences,sponsored by the Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences and Science Press.It is published by Science Press and Springer-Verlag Berlin Heidelberg bimonthly.JAL publishes original,innovative,and integrative research from arid and semiarid regions,ad     

The parasitoid complex ofLiriomyza cicerina on chickpea (Cicer arietinum)

Liriomyza cicerina (Diptera: Agromyzidae) is an important pest on chickpea in Turkey. The objective of this study was to determine the parasitoids and rates of parasitism ofL. cicerina on chickpea (Cicer arietinum L.) during the 2005 and 2006 seasons in ?anl?urfa province, Turkey. Leaves with mines were sampled weekly and kept in the laboratory to observe and count emerging leafminer and parasitoid adults. Eight parasitoid species were collected: the braconidsOpius monilicornis Fischer andOpius tersus Foerster and the eulophidsDiaulinopsis arenaria (Erdös) andNeochrysocharis formosa (Westwood), which occurred in both the winter and summer seasons;Diglyphus crassinervis Erdös,Neochrysocharis ambitiosa Hansson,Neochrysocharis sericea (Erdös) andPediobius metallicus (Nees), which occurred only in the summer growing areas.Diaulinopsis arenaria was the predominant parasitoid with 4–7.7% parasitism rate whileN. ambitiosa andO. monilicornis were the second and third most predominant species. The results of these trials show that sinceDia. arenaria occurred throughout every season, it could potentially be used for control of the leafminerL. cicerina.     

Plant–herbivore asynchrony necessitates augmentative releases of the exotic beetle,Zygogramma bicolorata,to enhance the biological control of P arthenium hysterophorus

Systematic information on the quantitative impact of Z ygogramma bicolorata on the biology of P arthenium hysterophorus is crucial as the seeds of this weed continue to germinate from the accumulated soil seed bank throughout the year in the form of different germinating flushes, while the activity of the beetle ceases during winter as it enters diapause. Therefore, plant–herbivore interactions need to be explored to develop predictions of the overall impact of the introduced beetle on the weed. The findings revealed that defoliation by Z . bicolorata had a significant impact on the plant height, density and flower production in flushes F ₃, F ₄ and F ₅, but not in F ₁ and F ₂ that exhibited longer periodicity, profuse branching, a longer flowering period and maximum flower production and contributed mostly to the existing seed soil bank. Therefore, total depletion of the existing soil seed bank was not possible. Consequently, the effect of augmentative field releases of laboratory‐reared beetles was explored on F ₁ and F ₂ in February for three consecutive years (2011–2013). Before initiating the trial, random soil samples were taken from the plots that were assigned to the paired treatments (i.e. with the beetle and without the beetle [insecticide‐treated]) and it was found that the seed bank in those samples did not differ. The single release of Z . bicolorata adults at five per plant at the six‐leaf stage significantly reduced the soil seed bank, compared to without the biocontrol agent, irrespective of the flushes at the end of the season.     

Richtlinien der Verbände des ökologischen Landbaus zum Vorratsschutz

Zusammenfassung Verbände des ökologischen Landbaus wie z. B. Bioland, Gäa, Demeter; Naturland, Ernte für das Leben oder Bio Suisse beschränken ihre Mitglieder bei der Wahl von Vorratsschutzmaßnahmen. Vorrang besitzen Maßnahmen zur Vermeidung von Schädlingen gegenüber Bekämpfungsmaßnahmen. Fallen müssen zur Befallsüberwachung eingesetzt werden, um einen Befall durch Vorratsschädlinge frühzeitig zu erkennen. Diese Maßnahmen sollen den weitgehenden Verzicht auf chemisch-synthetische Mittel ermöglichen. In diesem Beitrag werden die Empfehlungen der Verbände mit den derzeit verfügbaren chemischen Mitteln für den Vorratsschutz abgeglichen. Erfahrung in der praktischen Umsetzung von physikalischen und biologischen Verfahren werden diskutiert und Defizite bei der Befallsüberwachung und Bekämpfung beschrieben.     

Development of protocols for detection of Colletotrichum acutatum and monitoring of strawberry anthracnose using real-time PCR

Real-time PCR (TaqMan®) assays were developed for the specific detection and discrimination of Colletotrichum spp., C. acutatum and C. gloeosporioides causing anthracnose in strawberry using the most divergent area of the internal transcribed spacers (ITS1 and ITS2) and 5·8S ribosomal RNA (rRNA) gene region. The specificity of the new assays was tested using DNA from six species of Colletotrichum and nine fungal species commonly found associated with strawberry material, and additionally by comparing the sequences with those from databases using a blast search. The sequences only showed identity with homologous sequences from the desired target organisms. The new assays were 10–100 times more sensitive than conventional PCR methods previously published for the diagnosis of strawberry anthracnose. When real-time PCR was compared with ELISA methods, PCR improved the sensitivity of the identification by obtaining positive results for samples of strawberry plant material that tested negative with ELISA. The development of C. acutatum was monitored using artificially infected strawberry crowns from two strawberry cultivars (Camarosa and Ventana) and a real-time PCR assay specific for this species between January and June 2006. The amount of C. acutatum detected using real-time PCR varied significantly by month ( P  < 0·001), but not by cultivar ( P  = 0·394). The new assays were shown to be useful tools for rapid detection and identification of these pathogens and to allow rapid and accurate assessment of the casual agents of anthracnose in strawberry.     

Effects of the saprophytic leaf mycoflora on growth and productivity of winter wheat

The effects of the saprophytic mycoflora and its interference with cereal aphids on growth and yield of winter and spring wheat was studied in field experiments in 1980, 1981 and 1982.Yields varied between 5000 and 8000 kg dry matter of kernels per ha. The effect of the saprophytic mycoflora on yield was determined in different treatments: A) no control measures against cereal aphids and saprophytic and necrotrophic fungi, B) no control of cereal aphids, control of saprophytic and necrotrophic fungi, C) control of cereal aphids and control of saprophytic and necrotrophic fungi, D) control of cereal aphids and stimulation of saprophytic mycoflora and E) control of cereal aphids, no control of saprophytic and necrotrophic fungi nor stimulation of saprophytic mycoflora.Considerable differences in top densities of saprophytic mycoflora (10 times as large in A and D as in B and C) were determined. The consequences of these differences for the growth and productivity of wheat were minor. A negative effect of saprophytic mycoflora on the yield could not be detected in 1981 and 1982, whereas a small positive significant effect was found in 1980. This stimulation may have been due to competition between necrotrophic fungal pathogens and saprophytic mycoflora. As a result of favourable weather conditions necrotrophic fungal pathogens were very numerous in 1980 and could form an important yield reducing factor. Yield levels may effect the importance of the necrotrophic and saprophytic mycoflora as yield reducing factors. Additionally, in the presence of aphid honeydew captafol was found to be relatively ineffective against saprophytic fungi.     

Relationship Between Production of the Phytotoxin Prehelminthosporol and Virulence in Isolates of the Plant Pathogenic Fungus Bipolaris sorokiniana

A gas chromatographic method was developed to quantify the phytotoxin prehelminthosporol, which is a sesquiterpene metabolite of the plant pathogen Bipolaris sorokiniana. The toxin was extracted from mycelium or culture filtrates, pre-cleaned using solid phase extraction, and analyzed by gas chromatography as a trimethylsilyl-derivative. The detection limit of the method was 5ngl^–1 (signal to noise ratio 4:1) which corresponds to ca. 15ng prehelminthosporol per mg dry weight of mycelium or 15ng prehelminthosporol per ml culture filtrate. The total amount of prehelminthosporol (mycelium plus culture filtrate) increased with cultivation time when examined in six isolates of B. sorokiniana after 6, 9, 12 and 15 days of incubation. The screening experiment of 17 isolates for prehelminthosporol production after 8 days of incubation revealed significant differences in the toxin production between the isolates. The isolates with low toxin production had lower virulence towards barley roots compared to those with higher production of the toxin. However, the virulence did not increase with prehelminthosporol level among the high producing isolates. Prehelminthosporol was also analyzed in a number of related Bipolaris and Drechslera species. In addition to B. sorokiniana, three out of six Bipolaris species (B. setariae, B. zeicola, B. victoriae) produced prehelminthosporol, which indicates that ability to produce prehelminthosporol is conserved among closely-related Bipolaris species.