北京地区西洋参根腐病病原鉴定及其致病性

根腐病是北京地区栽培西洋参的主要病害之一,为了明确引起该类病害的病原菌,对北京怀柔区罹病西洋参参根进行了病原菌的分离及鉴定。结合形态学以及rDNA ITS区、转录延伸因子TEF 1α区的分子序列特征,对分离菌株的鉴定结果显示,分离频率较高的11个菌株分属于茄镰孢（Fusarium solani）、尖镰孢（F.oxysporum）、三线镰孢（F. tricinctum）、多育镰孢（F. proliferatum）、毁灭柱孢（Cylindrocarpon destructans）。通过柯赫氏法则验证,F. solani和F. oxysporum是引起北京地区栽培西洋参根腐病的主要病原菌;致病性测定结果发现F. solani不同菌株的致病性及致病力表现出明显差异。     

Prevalence and pathogenicity of spinach root pathogens of the genus Pythium in Sweden

Several pathogenic Pythium spp. were isolated from spinach roots in a 4-year disease survey in commercial spinach fields in southern Sweden. Heterothallic and zoospore-producing isolates belonging to the filamentous, non-inflated zoosporangia (F) group of van der Plaats-Niterink were most abundant, followed by P. sylvaticum, P. ultimum var. ultimum and P. heterothallicum. The heterothallic hyphal swelling (HS) group and P. tracheiphilum were found in a few plants. Two types of pathogenicity tests were performed, to measure the effects of seedling infection and of root infection of older plants. These tests showed P. ultimum var. ultimum to be the most severe spinach pathogen inducing pre- and post-emergence damping off as well as root rot of older plants. Also P. heterothallicum and P. tracheiphilum damaged both seedlings and older plants, Pythium sylvaticum, Pythium 'group HS' and Pythium 'group F'were pathogenic only to seedlings, P. ultimum var. ultimum and Pythium group F were isolated in significantly higher frequencies from spinach grown in the autumn season than in the spring. No clear relationships were found between Pythium prevalence and disease severity index of surveyed field plants, between Pythium prevalence and plant developmental stage, or between prevalence of Pythium and other pathogens isolated. This is the first report of P. heterothallicum and P. sylvaticum being pathogenic on spinach.     

Pathogenicity of fungi associated with winter loss and injury in white lupin

Fungi isolated from diseased white lupin plants were tested for pathogenicity in standardized glasshouse tests to assess their potential as causes of plant death in winter in autumn-sown crops. Pleiochaeta setosa and, to a slightly lesser extent, Fusarium avenaceum caused lesions or plant death when inoculated onto hypocotyls of lupin seedlings. Disease was more severe when the hypocotyls were wounded before inoculation. F. avenaceum also caused injury when inoculated onto roots; wounding the roots had no effect. Some isolates of F. solani also caused injury, especially after root inoculation, but isolates of F. oxysporum and Cylindrocarpon destructans were only slightly or non-pathogenic. Isolates of Fusarium and C. destructans , but not of P. setosa , differed in pathogenicity. There were differences in susceptibility to disease among three lupin cultivars.     

Fusarium spp. as a cause of crown and root rot of asparagus in Greece

Specimens of diseased asparagus (108) were selected from 17 fields in northern Greece. The asparagus crowns showed limited or widespread brown discoloration or extensive internal rot with fibrous tissues. A red-brown discoloration was also observed on the roots and, in a serious infection, most of the roots were totally destroyed and only their epidermis and ribbon-like central axis remained. 68 strains of Fusarium proliferatum , 25 of F. oxysporum , 19 of F. solani , and 1 strain of Rhizoctonia solani were isolated from crowns and roots. Single-spore isolates were subcultured from 50 strains of F. proliferatum , 21 of F. oxysporum and 7 of F. solani. These isolates were evaluated for pathogenicity by inoculating cultivar UC157F₁ of asparagus in an in vitro agar test-tube assay for 21 days at 29–32°C, with a light period of 16 h. Isolates of F. proliferatum and F. oxysporum were found to be the most pathogenic. The pathogenic F. oxysporum isolates were characterized as f.sp. asparagi.     

马铃薯干腐病菌和黑痣病菌拮抗芽胞杆菌的筛选及鉴定

从甘肃国营条山农场马铃薯连作试验田的96个小区以五点取样法采集根际土样,稀释平板法在LB培养基上分离得到625株芽胞杆菌菌株。统计分析表明,土壤中总芽胞杆菌的数量正茬〉连作2年〉连作4年,但连作6年的土壤中总芽胞杆菌的数量又有上升的趋势。以马铃薯干腐病菌接骨木镰刀菌FusariumsambucinumFSM、茄病镰刀菌FsolaniFSI、黑痣病菌立枯丝核菌RhizoctoniasolaniRSl和RS2为靶标病原菌,平板对峙培养法筛选有抑菌效果的拮抗芽胞杆菌,发现抑菌带宽度大于2mm的拮抗芽胞杆菌的数量随连作年限的增加而减少。以形态学特征、生理生化特性为基础,结合gyrB基因序列分析,将筛选出的2株拮抗效果较好且不引起马铃薯块茎腐烂的芽胞杆菌Bacillusspp．D1—0—1和D1—0—2鉴定为萎缩芽胞杆菌B．atrophaeus。     

黑龙江省马铃薯干腐病菌种类鉴定及致病性

本研究将采自黑龙江省不同地区的马铃薯干腐病病样进行分离和病原菌纯化,得到27个镰刀菌菌株,通过致病性鉴定,其中的18个菌株具有致病性。运用培养性状和形态特征综合分析的方法,对上述18个菌株进行鉴定,结果显示为6种镰刀菌,分别为拟枝孢镰孢(Fusarium sporotrioides)、茄镰孢(F.solani)、接骨木镰孢(F.sam-bucinum)、拟丝孢镰孢(F.trichothecioides)、燕麦镰孢(F.avenaceum)和茄病镰孢蓝色变种(F.solanivar.coerule-um)。同时对上述6种镰刀菌进行致病性测定,结果表明不同种类镰刀菌致病性不同,以接骨木镰孢、燕麦镰孢和拟丝孢镰孢致病力最强,拟枝孢镰孢致病力最弱。     

Detection and recovery of Rhizoctonia solani in naturally infested glasshouse soils using a combined baiting, double monoclonal antibody ELISA

A combined baiting, double monoclonal antibody immunoassay was developed that allows specific and sensitive detection of the economically important soil-borne plant pathogen Rhizoctonia solani in naturally infested soils. The assay is quick, taking only three days to complete from receipt of soil samples and the immunoassay format allows recovery of Rhizoctonia isolates from colonized baits for determination of anastomosis group (AG) affiliation and pathogenicity. The assay was tested on naturally infested soils from commercial glasshouses used to grow lettuce. Using the immunoassay, conventional anastomosis tests against known AG isolates, and pathogenicity tests, it was shown that R. solani isolates recovered from soil samples were pathogenic towards lettuce and belonged to AG4. Furthermore, those isolates that exhibited strong pathogenicity towards lettuce were recovered from sites that had experienced severe Rhizoctonia damage in previous lettuce crops. The possibility of developing a preplanting test to predict damage to specific crop plants due to the presence of particular AGs in the soil is discussed.     

甘肃枸杞镰孢菌根腐病病原鉴定及优势病原菌生物学特性

为了明确甘肃省枸杞根腐病病原种类、生态分布和优势病原菌的生物学特性,于2013年和2014年采集甘肃省各枸杞主产区根腐病患病植株样品,分离纯化后进行形态和分子鉴定,统计分离到的各主产区的病原种类,并对优势病原菌的适宜生长温度、光照条件、pH和碳氮源进行了研究。结果共分离到260株镰孢菌菌株,其中GSJT7-2和GSJY8-1分离频率分别为66.15%和26.92%,属优势种;将2株镰孢菌进行EF-1α基因序列分析及对比,菌株GSJT7-2(登录号:KM457089)与腐皮镰孢菌(Fusarium solani),GSJY8-1(登录号:KM457093)与尖镰孢菌(F.oxysporium)同源性达99%,在系统发育树中聚在一起,分别将它们的分类地位初步确定为腐皮镰孢菌和尖镰孢菌。甘肃各产区病原菌分离种类和频率有较大差异,靖远县以尖镰孢菌为主,占82.89%;其余采集地均以腐皮镰孢菌为主,均占80%以上。腐皮镰孢菌GSJT7-2和尖镰孢菌GSJY8-1在10~40℃内均能生长,最适温度分别为35℃和25℃,最适pH为8~9和8,均在12 h光暗交替条件下生长最快,供试碳氮源中GSJT7-2和GSJY8-1对蔗糖和Na NO3利用效果最好。     

Resistance Reaction of Conifer Species (European Larch, Norway Spruce, Scots Pine) to Infection by Selected Necrotrophic Damping-off Pathogens

Three conifer species (European larch, Norway spruce, Scots pine) were investigated for their resistance to five damping-off pathogens (Rhizoctonia solani, Fusarium solani, F. oxysporum, F. culmorum, F. avenaceum). Inoculation of the primary roots of seedlings with these pathogens caused host cell death which did not prevent the invasive growth of these fungi; seedlings that had formed secondary and tertiary roots could overcome the infection to a significant degree. Infections with R. solani caused significant mortality to all the conifer species. In contrast, the tree species expressed different levels of resistance when challenged with the Fusarium isolates, with Norway spruce being the most resistant compared to uninoculated controls. Some of the Fusarium isolates were more pathogenic to certain hosts than others; F. oxysporum for European larch, F. avenaceum for Scots pine, F. solani for European larch; only F. culmorum was significantly pathogenic to Norway spruce. No significant differences in disease severity were observed at different soil pH (4.3–7.5). Disease progression was delayed at lower (10–15°C) rather than higher temperatures (20–25°C).     

Biological Control of Pathogens Causing Root Rot Complex in Field Pea Using Clonostachys rosea Strain ACM941

ABSTRACT Pea root rot complex (PRRC), caused by Alternaria alternata, Aphanomyces euteiches, Fusarium oxysporum f. sp. pisi, F. solani f. sp. pisi, Mycosphaerella pinodes, Pythium spp., Rhizoctonia solani, and Sclerotinia sclerotiorum, is a major yield-limiting factor for field pea production in Canada. A strain of Clonostachys rosea (syn. Gliocladium roseum), ACM941 (ATCC 74447), was identified as a mycoparasite against these pathogens. When grown near the pathogen, ACM941 often was stimulated to produce lateral branches that grew directly toward the pathogen mycelium, typically entwining around the pathogen mycelium. When applied to the seed, ACM941 propagated in the rhizosphere and colonized the seed coat, hypocotyl, and roots as the plant developed and grew. ACM941 significantly reduced the recovery of all fungal pathogens from infected seed, increased in vitro seed germination by 44% and seedling emergence by 22%, and reduced root rot severity by 76%. The effects were similar to those of thiram fungicide, which increased germination and emergence by 33 and 29%, respectively, and reduced root rot severity by 65%. When soil was inoculated with selected PRRC pathogens in a controlled environment, seed treatment with ACM941 significantly increased emergence by 26, 38, 28, 13, and 21% for F. oxysporum f. sp. pisi, F. solani f. sp. pisi, M. pinodes, R. solani, and S. sclerotiorum, respectively. Under field conditions from 1995 to 1997, ACM941 increased emergence by 17, 23, 22, 13, and 18% and yield by 15, 6, 28, 6, and 19% for the five respective pathogens. The seed treatment effects of ACM941 on these PRRC pathogens were greater or statistically equivalent to those achieved with thiram. Results of this study suggest that ACM941 is an effective bioagent in controlling PRRC and is an alternative to existing chemical products.     

Incidence of soil-borne plant pathogens isolated from barley and winter wheat, and other crops in the rotation, on Prince Edward Island

Barley and winter wheat were sampled over 3 years to characterize soil-borne organisms involved with cereal crown and root disease complexes. Winter wheat crowns were infected more often by Fusarium avenaceum and F. sambucinum than barley crowns. Bipolaris sorokiniana and F. graminearum were more common in crown tissue of barley underseeded with clover than in winter wheat crowns. In roots, the incidence of F. avenaceum was highest in winter wheat. In soil, populations of Rhizoctonia solani and F. sambucinum were higher in winter wheat than barley underseeded with ryegrass. Stunt nematodes (Tylenchorhynchus spp.) were greatest in winter wheat and barley underseeded with ryegrass. The incidence of F. avenaceum in roots of winter wheat correlated positively with the severity of crown and root rot symptoms. The severity of barley crown and root rot correlated positively with the incidence of R. solani in crowns, F. avenaceum in crowns and roots, B. sorokiniana in roots, and numbers of stunt nematodes in the soil. The incidence of soil-borne organisms was also recorded in annual ryegrass. soybean, potato, pea, and clover which were grown in rotation with barley and winter wheat. The incidence of R. solani and F. avenaceum was highest in clover crown tissue, and F. sambucinum was prevalent in soybean hypocotyls. Soil population levels of R. solani, F. avenaceum , and stunt nematodes were greatest in ryegrass and pea soil just prior to ploughing down or harvesting these crops, respectively.     

浙江省荸荠上镰刀菌种类及其致病性

作者从浙江省11个县市采集病、健株及球茎标样共669个,经分离、纯化、鉴定,获以下7个镰刀菌种;尖孢镰刀菌(Fusarium oxysporum)、锐顶镰刀菌(F.acuminatum)、半裸镰刀菌(F.semitectum)、层出镰刀菌(F.proliferatum)、茄病镰刀菌(F.solani)、禾谷镰刀菌(F.graminearum)和木贼镰刀菌(F.equiseti)。田间观察和接种试验证明:F.oxysporum是引起荸荠茎秆枯萎的主要病原,这是一种新的危险性病害。病株矮小、黄化、基腐、后期倒伏。1986～1990年少数县市发病率达40％～50％。人工接种证明:F.acuminatum也属强致病性的种类。而F.proliferatum和F.solani则是引起贮藏期球茎腐烂的主要病原。其余种类仅具微弱或无致病性。     

非洲菊根腐病病原的鉴定与ITS序列分析

 从南京花卉苗圃的非洲菊腐烂病植株的根部分离到46株真菌菌株,将所有菌株回接到健康的植株上,结果发现只有11个疫霉菌菌株可以引起非洲菊典型的根腐病症状。对上述疫霉菌的形态特征、致病性及核糖体DNA-ITS序列进行分析,结果为所有菌株在LBA平板上菌落圆形、呈放射状、菌丝致密、气生菌丝较丰富、菌丝无隔,能形成大量菌丝膨大体,水培后产生大量椭圆形孢子囊,孢子囊无乳突,游动孢子在孢子囊内形成。进一步克隆并分析供试菌株核糖体DNA-ITS区域的序列,结果是分离菌株与GenBank中隐地疫霉的ITS序列的同源性均为99.87%,仅有1个碱基的差异,进一步明确了本研究中从非洲菊腐烂病植株根部分离的病原菌为隐地疫霉(Phytophthora cryptogea)。     

Fungi on roots and stem bases of asparagus in the Netherlands: species and pathogenicity

A survey was made to identify the most important soilborne fungal pathogens of asparagus crops in the Netherlands. Ten plants were selected from each of five fields with a young (1–4 y) first planting, five fields with an old (6–13 y) first planting and five fields with a young replanting. The analysis included fungi present in the stem base and the roots of plants with symptoms of foot and root rot or showing growth decline without specific disease symptoms. Isolates of each species were tested for pathogenicity to asparagus on aseptically grown plantlets on Knop's agar. Symptoms were caused byFusarium oxysporum, F. culmorum, Botrytis cinerea, Penicillium verrucosum var.cyclopium, Cylindrocarpon didymum, Phialophora malorum, Phoma terrestris andAcremonium strictum. F. oxysporum was by far the most common species and was isolated from 80% of the plants. Not all of its isolates were pathogenic to asparagus. Symptoms were caused by 67%, 78% and 93% of the isolates obtained from young first plantings, old first plantings and replantings, respectively.F. culmorum was isolated from 31% of the plants. Two other notorious pathogens of asparagus,F. moniliforme andF. proliferatum, did not occur in our samples.Species causing symptoms in the vitro test that were found on more than 5% of the plants were additionally tested for their pathogenicity in pot experiments.F. oxysporum f.sp.asparagi caused severe foot and root rot, significantly reduced root weights and killed most of the plants.F. culmorum caused lesions on the stem base often resulting in death of the plant.P. terrestris, a fungus only once reported as a pathogen of asparagus, caused an extensive root rot, mainly of secondary roots that became reddish. The fungus was isolated in only a few samples and is not to be regarded as an important pathogen in Dutch asparagus crops.P. malorum caused many small brown lesions on the stem base and incidentally also on the upper part of small main roots. This is the first report of its pathogenicity to asparagus. The fungus is one of the organisms inciting spear rust and it reduced crop quality rather than crop yield.P. verrucosum var.cyclopium andC. didymum did not cause symptoms in pot experiments.Because of its predominance on plants with foot and root rot and its high virulence,F. oxysporum f.sp.asparagi was considered to be the main soilborne pathogen of asparagus in the Netherlands.     

载银无机抗菌制剂对大豆根腐病的防治效果

 测定了广泛用于工业和日用品的载银无机抗菌制剂Zeomic和AM₁对大豆根腐病重要病原菌Fusarium oxysporum、Fusarium solani和Rhizoctonia solani孢子萌发和菌落扩展的抑制作用。结果表明,Zeomic在浓度为500 mg/L时可以完全抑制F. oxysporum和F. solani的孢子萌发,但对F. oxysporum、F. solani和R. solani菌落扩展的抑制作用较弱,分别为7.4%、0.0%和3.7%。AM₁对病菌孢子萌发的抑制作用随浓度的升高而增强,在浓度为250 mg/L时对F. solani孢子萌发的抑制率为18.8%,到1 000 mg/L时可完全抑制。但AM₁在浓度为1 000 mg/L时对F. oxysporum的孢子萌发抑制率只有29.7%,表明不同菌类对AM₁的敏感性不同。同一浓度下的AM₁对F. oxysporum菌落扩展的抑制率大于对F. solani和R. solani菌落扩展的抑制作用,在500 mg/L时对病菌的抑制率分别为51.4%、14.6%和11.0%。温室内对大豆生长的调查结果表明,用种子重量0.05%和0.10%的AM₁拌种对出苗和生长有促进作用,Zeomic用量在0.05%时不影响出苗、株高和根系干物质积累,但当用量增加至0.10%时,则表现对出苗和干物质累积的抑制作用。田间试验结果表明,500m g/L的AM₁拌种对大豆根腐病防效为32.6%,与化学农药35%多克福包衣处理无显著差异,但比后者增产10.1%。由此说明,载银无机抗菌制剂具有用于农作物病害防治的潜力。     

Characterization of Fusarium spp. responsible for causing dry rot of potato in Great Britain

A 3-year survey was undertaken to establish the relative frequency of different Fusarium spp. present as inoculum on potato tubers collected from four regions of Great Britain. A total of 219 samples (comprising 10 950 tubers) were collected from the 2000, 2001 and 2002 crops and processed to recover dry rot-producing isolates. In total, 228 isolates of Fusarium spp. were recovered. Most (94·7%) of these isolates were attributed to one of four Fusarium species: F. coeruleum, F. avenaceum, F. culmorum and F. sambucinum (formerly F. sulphureum) . The incidence of the combined Fusarium spp. increased the further south the crops had been grown. Fusarium coeruleum was the most commonly isolated species in each survey year, comprising 37 to 52% of the total Fusarium species. Selected isolates of each species were evaluated for their ability to produce rots in potato tubers. Fusarium sambucinum was a more aggressive pathogen than the other Fusarium species in eight out of 10 cultivars. Fusarium avenaceum and F. culmorum were relatively weaker pathogens. However, these species were aggressive on some cultivars, notably Hermes. The selected isolates were also assessed for their sensitivity to the fungicides thiabendazole and imazalil. Using in vitro tests, 65% of F. sambucinum isolates were resistant to thiabendazole and 7% of F. avenaceum isolates were resistant to imazalil. Tubers treated with imazalil yielded a higher proportion of isolates of F. avenaceum than those that were untreated. Similarly, a higher proportion of F. sambucinum isolates were recovered from tubers treated with thiabendazole than from those that were not treated.     

Effect of inoculum source on root and tuber infection by potato blemish disease fungi

The incidence of potato pathogens on healthy roots of micropropagated (MP) and seed tuber (ST) plants was examined on successive dates during the growing season in two field experiments. Microplants were grown in a glasshouse for 4–5 weeks in perlite or peal-based substrates, and exposed or not to natural inoculum before planting in the field. The seed tubers originated from stocks of visually clean or moderately blemished tubers and were surface-sterilized or not before planting. Polyscytalum pustulans and Helminthosporium solani only infected roots of ST plants and inoculated MP plants. The incidence of P. pustulans was affected by seed tuber-borne inoculum and, in I year, by the substrate. H. solani was detected infrequently on roots. Rhizoctonia solani was present at low frequencies in most root samples, and more ST than MP plant roots were colonized; there were no substrate effects. In 1 year, increased inoculum levels increased root infection, but only in MP roots. Colletotrichum coccodes occurred at high frequencies and was most common in roots of ST plants. Progeny tubers showed some treatment effects when tested in September and after storage for 6 months, but there were no consistent relationships between root and progeny tuber infection.     

枸杞根腐病的发生及防治研究

宁夏枸杞根腐病普遍发生。作者对其病原进行了分离鉴定,有4种病原菌:尖孢镰刀菌(Fusarium oxysporum Schlecht)、腐皮镰刀菌[F.solani(Mart,)Sacc]、同色镰刀菌(F.concolor Reinking)和串珠镰刀菌(F.moniliforme Sheldon)。其中尖孢镰刀菌致病力最强。对上述病原的生长温度、pH值作了室内测定。此病病原菌能随病株、病残体和病果种子越冬。枸杞不同品种对此病抗性有明显差异。田间积水和根部损伤利于发病。45％代森铵药液灌根对此病有良好的防治效果;培土垄作和中耕时不伤根的防治效果达74.4％。     

Identification and Pathogenicity of Rhizoctonia spp. Isolated from Apple Roots and Orchard Soils

ABSTRACT Rhizoctonia spp. were isolated from the roots of apple trees and associated soil collected in orchards located near Moxee, Quincy, East Wenatchee, and Wenatchee, WA. The anastomosis groups (AGs) of Rhizoctonia spp. isolated from apple were determined by hyphal anastomosis with tester strains on 2% water agar and, where warranted, sequence analysis of the rDNA internal transcribed spacer region and restriction analysis of an amplified fragment from the 28S ribosomal RNA gene were used to corroborate these identifications. The dominant AG of R. solani isolated from the Moxee and East Wenatchee orchards were AG 5 and AG 6, respectively. Binucleate Rhizoctonia spp. were recovered from apple roots at three of four orchards surveyed and included isolates of AG-A, -G, -I, -J, and -Q. In artificial inoculations, isolates of R. solani AG 5 and AG 6 caused extensive root rot and death of 2- to 20-week-old apple transplants, providing evidence that isolates of R. solani AG 6 can be highly virulent and do not merely exist as saprophytes. The effect of binucleate Rhizoctonia spp. on growth of apple seedlings was isolate-dependent and ranged from growth enhancement to severe root rot. R. solani AG 5 and AG 6 were isolated from stunted trees, but not healthy trees, in an orchard near Moxee, WA, that exhibited severe symptoms of apple replant disease, suggesting that R. solani may have a role in this disease complex.     

云南灯盏花根腐病的2种新病原鉴定及防治药剂的室内筛选

引起云南省灯盏花根腐病的病原为茄病镰刀菌(Fusarium solani)、尖孢镰刀菌(F.oxysporum)和半裸镰刀菌(F.semitectum)3种真菌,茄病镰刀菌和尖孢镰刀菌为灯盏花根腐病的2种新病原,其中茄病镰刀菌为主要致病菌,其分离率为42.86%,茄病镰刀菌有伤接种发病率为70%,无伤接种发病率为56.7%。采用室内生长速率法测定了50%多菌灵可湿性粉剂、70%甲基硫菌灵可湿性粉剂、64%恶霜·锰锌可湿性粉剂、10%苯醚甲环唑水分散粒剂、10亿活芽胞/g 枯草芽胞杆菌·荧光假单胞杆菌可湿性粉剂5种供试杀菌剂对灯盏花根腐病主要病原茄病镰刀菌的毒力。结果表明：5种供试药剂对茄病镰刀菌都有抑制作用。对茄病镰刀菌的有效中浓度（EC50）分别为0.000 4、0.050 7、0.053 5、0.081 3和8.624 0 mg/mL,其中50%多菌灵可湿性粉剂有效中浓度最低,相对抑制效果最好。5种药剂的毒力相关系数均在0.89以上,表明药剂质量浓度与抑制作用呈较高相关性。