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1.
火龙果溃疡病病原菌鉴定及生物学特性   总被引:1,自引:0,他引:1  
为确定火龙果溃疡病病原菌,应用柯赫氏法则测定了从病样中分离的纯培养物的致病性,根据形态学特性和ITS序列分析对病原菌进行鉴定,并采用菌落生长法和玻片法研究了其生物学特性.结果表明,火龙果溃疡病的病原菌为新暗色柱节孢Neoscytalidium dimidiatum (Penz.) Crous & Slippers.碳氮源对病原菌菌丝生长和产孢量的影响差异明显,菌丝生长和产孢的最佳碳源为蔗糖,菌丝生长最佳氮源为酵母膏,产孢最佳氮源为甘氨酸.温度、pH对病原菌菌丝生长、产孢和孢子萌发的影响差异显著,菌丝生长、产孢、孢子萌发的最佳温度均为30℃;菌丝生长最佳pH为8,产孢和孢子萌发最佳pH为7.光照对病原菌菌丝生长和产孢有抑制作用,对孢子萌发没有明显影响.相对湿度高有利于孢子萌发,高于98%时,萌发率达100%.  相似文献   

2.
云南省荞麦叶枯病病原菌鉴定及其生物学特性   总被引:1,自引:0,他引:1  
为明确云南省荞麦叶枯病病原菌种类,采用常规组织分离法获得病原菌菌株LW2015.3,通过形态学特征及分子生物学技术对菌株LW2015.3进行鉴定,并研究其生物学特性。结果表明,荞麦叶枯病病原菌的分生孢子呈倒棍棒状或倒梨状,褐色,具3~8个横隔膜,0~4个纵斜隔膜,大小为16.5~45.0μm×5.0~13.5μm,厚垣孢子呈球形,直径为6.0~12.0μm;该菌株ITS序列系统发育进化分析结果表明,菌株LW2015.3与链格孢Alternaria alternata(登录号:MG195995.1)的同源性为100%,结合形态学特征与分子鉴定结果确定云南省荞麦叶枯病病原菌为链格孢A. alternata(登录号:KT362732.1)。该病原菌菌丝生长适宜温度为20~30℃,25℃为最适温度;当p H为6~9时菌丝生长速率加快,pH 7最适菌丝生长;PDA培养基和PSA培养基最适菌丝生长;该病原菌对以麦芽糖为碳源和以硝酸钠为氮源时的利用率最高;菌丝的致死温度为50℃,10 min;不同光照条件对菌丝生长的影响有显著差异,连续光照最有利于菌丝生长。  相似文献   

3.
本研究采用PSA培养基对上海地区的番茄棒孢叶斑病的病原菌进行分离、培养及致病性测定,通过形态学和分子生物学方法鉴定病原菌,并对该病菌的生物学特性进行研究。结果表明:番茄棒孢叶斑病病原菌菌落呈灰褐色,菌丝质地致密、绒毛状;分生孢子单生或串生,圆柱形或倒棍棒形、顶端钝圆,基部平截,呈半透明至浅褐色,假隔膜4~10个,直或稍弯曲,基脐加厚,深褐色。结合病原菌rDNA ITS序列测定、比对后,确定该病原为多主棒孢Corynespora cassiicola。该病菌的菌丝生长最适温度为25~30℃,最适pH范围为4~8,产孢的最适温度约为25℃,最适pH范围为5~9,麦芽糖和乳糖为碳源的培养基适宜菌丝生长,可溶性淀粉和乳糖溶液中孢子萌发率最高,光暗交替条件适宜菌丝生长,孢子在水滴中极易萌发。这是该病在上海地区的首次报道。  相似文献   

4.
为明确引起贵州八角叶枯病的病原种类及其生物学特性, 本研究采用单孢分离法获得3个菌株, 经形态学特征鉴定结合ITS?tef1和TUB多基因序列分析, 3个菌株均被鉴定为庐山拟盘多毛孢Pestalotiopsis lushanensis, 这是该菌在八角上引起叶枯病的首次报道?生物学特性研究表明, 该菌菌丝生长和孢子萌发最佳温度为25℃, 最适pH为6~7, 菌丝致死温度为50℃处理10 min, 分生孢子致死温度为55℃处理10 min?  相似文献   

5.
为明确山东省蓝莓叶斑病病原菌的种类及其生物学特性,采用组织分离法获得菌株B1,通过形态学特征并结合r DNA-ITS序列分析对该菌株B1进行鉴定,以离体和活体叶片接种法测定菌株B1的致病性,并对其生物学特性进行研究。结果表明,菌株B1菌落呈白色绒毛状,背面淡黄色,分生孢子纺锤形,5个细胞,中间3个细胞为褐色,具有2~4根顶端附属丝;菌株B1的ITS序列与GenBank中棒状拟盘多毛孢Pestalotiopsis clavispora的相似性达99%以上,结合形态特征与rDNAITS序列分析将病原菌鉴定为棒状拟盘多毛孢,GenBank登录号为MG009201。菌株B1接种蓝莓叶片后产生褐色病斑,后期密生黑色分生孢子盘,与蓝莓田间自然发病症状一致。该菌株在5~35℃、pH 5~11范围内均可生长,最适温度范围为25~30℃,最适pH范围为5~9;但仅在25~30℃时产生分生孢子,最适产孢温度为25℃;光照条件对菌丝生长无明显影响,但连续黑暗有利于产孢;以葡萄糖为碳源时利用率最高,对乳糖利用效果最差;最适氮源为硝酸钠、硫酸铵和蛋白胨,几乎不能利用尿素。  相似文献   

6.
水葫芦生防菌Cercospora piaropi菌株BA-57的生物学特性   总被引:1,自引:1,他引:1  
尾孢菌属的Cercospora piaropi是一种水葫芦生防真菌,有潜力被开发成为防除水葫芦的真菌除草剂。本试验研究了该菌BA-57菌株的生物学特性。结果表明,BA-57菌丝生长、产孢和孢子萌发的最适温度都为30℃,最适pH分别为7.6、10.0和9.0。光照处理对BA-57的菌丝生长以及产孢量无显著影响,而全黑暗有利于孢子萌发。碳源中,甘露醇最适于BA-57菌丝生长,而葡萄糖和蔗糖有利于BA-57产孢。BA-57菌丝生长和产孢的最佳氮源都是硝酸钠。蛋白胨和玉米粉对BA-57的孢子萌发有促进作用。湿度条件,在水滴中BA-57的孢子萌发率最高。  相似文献   

7.
为明确采自西双版纳景洪地区疑似橡胶麻点病的病原菌,采用组织分离法进行病原菌分离,活体接种法进行致病性测定,通过形态学观察结合rDNA-ITS和GAPDH两个核苷酸片段序列分析,将病原菌确定为狗尾草平脐蠕孢Bipolaris setariae。通过单因子变量试验,对病原菌进行生物学特性研究,结果表明:菌丝生长最适温度为30℃,最适pH为7~8,最适培养基为PDA,菌丝致死温度为53℃,10 min。该病原菌能有效利用多种碳源和氮源,碳源以可溶性淀粉利用率最高,最适氮源为蛋白胨。24 h黑暗条件下培养更有利于菌丝生长。分生孢子萌发的最适温度为28~35℃,最适pH为7~8,28℃黑暗培养2 h后萌发率达到最大,为95.5%,分生孢子致死温度为60℃,10 min。  相似文献   

8.
 明确黄脉爵床棒孢霉叶斑病病原菌及其生物学特性,为防控提供理论依据。通过病原菌分离、形态特征观察、致病性测定、rDNA-ITS序列分析、生物学特性及寄主范围测定等研究,证明该病病原菌为山扁豆生棒孢Corynespora cassiicola;菌丝生长及产孢适宜温度20℃~28℃,孢子萌发适宜温度24℃~32℃,菌丝致死温度49℃处理10 min;菌丝生长适宜pH 6~10,产孢适宜pH 4~8,孢子萌发最适pH 8;光暗交替适合菌丝生长与产孢,连续光照可抑制菌丝生长;菌丝生长量由少到多培养基顺序为CA、PCA、PDA、CMA、OA,而PDA上产孢最多;刺伤接种,病菌可侵染喜树(Camptotheca acuminata)等植物。黄脉爵床棒孢霉叶斑病病原为山扁豆生棒孢C. cassiicola,病菌易产孢,寄主广,潜育期短。该病菌侵染黄脉爵床为首次报道。  相似文献   

9.
为明确引起云南核桃叶枯病的病原及其生物学特性,本文对分离自叶枯病病斑上的一株拟盘多毛孢进行了形态学和分子生物学鉴定,并通过柯赫氏法则验证其致病性;采用生长速率法、悬滴法和载玻片法研究其菌丝生长和孢子萌发的生物学特性。结果表明,该菌株为小孢拟盘多毛孢Pestalotiopsis microspora,是引起云南核桃叶枯病的新病原。该病原菌的最适生长温度为20~25℃,最适光周期L//D=12 h//12 h,最适生长pH为4~8。病原菌的分生孢子萌发受pH和湿度的影响较大,在中性及碱性环境下不萌发,最适萌发pH为4~5;在高于90%的相对湿度下才能萌发。分生孢子在20~25℃下萌发率最高,全光照最适于孢子萌发;核桃叶汁液对分生孢子萌发有显著的促进作用。  相似文献   

10.
[目的] 明确引起短穗鱼尾葵灰斑病的病原菌及该菌的生物学特性。[方法] 从短穗鱼尾葵感病组织上分离、纯化病菌,经致病性测定后根据其形态特征进行种类鉴定,并测定其在不同培养条件下的生物学特性。[结果] 引起短穗鱼尾葵灰斑病的病原菌为小孢拟盘多毛孢菌[Pestalotiopsis microspora (Speg.) Satista &; Peresapud Batista]。该菌在PSA 培养基上长势最好;菌丝生长和孢子萌发的最适温度为25 ℃;完全光照条件最利于菌丝的生长和产孢;在pH5时菌丝生长最好,pH6时孢子萌发率最高,pH2时孢子不萌发;孢子的致死温度为50 ℃。[结论] 上述结果可以为短穗鱼尾葵灰斑病的防治提供依据。  相似文献   

11.
In 1975 many tumours were observed in plants ofBegonia Schwabenland grown in Aalsmeer. Submersion of the roots ofNicotiana megalosiphon seedlings in a homogenate of tumorous tissue, induced tumours after two weeks. Short periods of submergence yielded results similar to those obtained after longer periods. Tumour homogenates lost their infectivity after ten min at 50°C. Aphids transmitted the infectious agent.Treatment with propylene oxide did not inhibit infectivity completely. Filtration through a 450 nm filter removed the infectious agent.Tobacco tumor virus or a viroid could not be isolated. Cultures ofCorynebacterium fascians, isolated from tumours ofN. megalosiphon were highly infectious and induced tumours in healthyN. megalosiphon andBegonia. Tumorous tissue homogenates ofPelargonium zonale, Dahlia sp.,Gladiolus sp., andLilium sp. also caused tumours inN. megalosiphon, from whichC. fascians was isolated. It was not possible to produce tumours inN. megalosiphon with homogenates from roses with symptoms of bud proliferation.Samenvatting In 1975 werden vele tumoren waargenomen inBegonia Schwabenland op Aalsmeerse bedrijven (Fig. 1). De infectiositeit van tumorweefsel kon goed en snel worden vastgesteld door de wortels van zaailingen vanNicotiana megalosiphon in een homogenaat van tumorweefsel te dompelen. Tumoren ontstonden na twee weken, de eindbeoordeling geschiedde na een maand (Fig. 2). Ook verschillende andereNicotiana spp.,Melilotus officinalis (Fig. 3) enPisum odoratum (Fig. 4) werden aangetast.Bij de infectiositeitstoets gaven zeer korte dompeltijden even goede resultaten als langere (Tabel 1). Infectieus sap verloor zijn infectievermogen na 10 min verhitting bij 50°C. Bladluizen brachten de smetstof over. Propyleenoxide verminderde de infectiositeit wel, doch onderdrukte deze niet totaal. Bij filtratie door een 450 nm filter bleef het infectieuse agens op het filter achter. Het tumor-inducerende agens was ook aanwezig in die delen van planten met tumoren welke gezond leken en het ging voor een gering deel over met zaad (Tabel 2).Uit tumoren konden wij geen tabakstumorvirus of een viroïde isoleren. Culturen vanCorynebacterium fascians, geïsoleerd uit tumoren vanN. megalosiphon bleken zeer infectieus en veroorzaakten tumoren inN. megalosiphon enBegonia. Homogenaten van tumorweefsel vanPelargonium zonale, dahlia (Fig. 5), gladiool (Fig. 6) enLilium Mid Century Hybrid Enchantment (Fig. 7) veroorzaakten ook tumoren opN. megalosiphon, waaruitC. fascians werd geïsoleerd. Met sap van kroeskopzieke rozen konden wijN. megalosiphon niet besmetten.  相似文献   

12.
Plant Viruses Transmitted by Whiteflies   总被引:18,自引:0,他引:18  
One-hundred and fourteen virus species are transmitted by whiteflies (family Aleyrodidae). Bemisia tabaci transmits 111 of these species while Trialeurodes vaporariorum and T. abutilonia transmit three species each. B. tabaci and T. vaporariorum are present in the European–Mediterranean region, though the former is restricted in its distribution. Of the whitefly-transmitted virus species, 90% belong to the Begomovirus genus, 6% to the Crinivirus genus and the remaining 4% are in the Closterovirus, Ipomovirus or Carlavirus genera. Other named, whitefly-transmitted viruses that have not yet been ranked as species are also documented. The names, abbreviations and synonyms of the whitefly-transmitted viruses are presented in tabulated form together with details of their whitefly vectors, natural hosts and distribution. Entries are also annotated with references. Whitefly-transmitted viruses affecting plants in the European–Mediterranean region have been highlighted in the text.  相似文献   

13.
During a survey conducted from 1998 to 2002, Fusarium proliferatum was found associated with young and adult palms belonging to the genera Chamaerops, Phoenix, Trachycarpus and Washingtonia showing symptoms of wilt and dieback. The fertility and toxicological profile of 36 strains representing different locations and hosts were studied. All of them except two, which were infertile, belonged to mating population D. Both mating types (MATD-1 and MATD-2) were isolated from the same host species, showing a high potential of genetic recombination in the field. Additionally, eight strains were fertile once crossed as female. Toxin analysis showed differences in the ability of strains to produce fumonisin B1, moniliformin, beauvericin, fusaric acid and fusaproliferin. Only 17 of them produced all the toxins analyzed. Pathogenicity tests were conducted on Phoenix dactylifera and P. canariensis using nine F. proliferatum Spanish strains and two reference strains from Saudi Arabia. Eight months after inoculation all strains caused disease, with palms showing lesions on the bases of leaves and development of wilt symptoms similar to those originally observed in affected plants. This is the first report on the occurrence of F. proliferatum on P. dactylifera in Spain and also the first report of this pathogen on C. humilis, P. canariensis, P. reclinata, T. fortunei, W. filifera and W. robusta.  相似文献   

14.
The epidemiology ofSitobion avenae and its natural enemies in winter wheat was studied in 1975, 1976 and 1977. Immigration was important until the end of flowering. The alate immigrants had apterous offspring. These became the driving force in population growth. Their offspring were mostly alatae which usually left the field. A model of the epidemic was developed. Quantitative relations between the aphids and their environment were obtained from literature or established in laboratory trials. The model simulated population development and population composition from the beginning of June till the population peak at the end of June or early in July. Because quantitative data on relations between aphids and their natural enemies and pathogens are scarce, and since the knowledge on wing formation is still limited, the population collapse could not be predicted. In the future, prognosis over a period of three weeks seems possible.Samenvatting De toenemende betekenis van graanbladluizen (vooralSitobion avenae) gepaard gaande met een sterke toename van het gebruik van insecticiden op granen maakte verbetering van de prognose over het schadelijk optreden wenselijk. Door gedetailleerde tellingen in het veld (Fig. 1–7) werden gegevens verkregen over het verloop van de epidemie en het optreden van natuurlijke vijanden in 1975, 1976 en 1977.Een immigratieperiode tot in de bloei kon worden vastgesteld. Daarna lijkt de aantrekkelijkheid van het gewas voor alate luizen te verminderen. De alate immigranten krijgen aptere nakomelingen. Deze vormen de stuwende kracht van de populatiegroei. De nakomelingen van apteren zijn merendeels alaat. Zij verlaten het gewas.Een model van de populatieontwikkeling gedurende de epidemie werd opgesteld. De relatiediagrammen Fig. 9 en 10 laten groei en ontwikkeling vanS. avenae en een predator (Syrphus corollae) zien. Kwantificering van de betrekkingen werd mogelijk door literatuurgegevens en laboratoriumexperimenten.Met het model kon de populatieontwikkeling vanS. avenae vanaf begin juni tot aan de populatiepiek in 1975, 1976 en 1977 vrij goed worden gesimuleerd (Fig. 12). Ook de populatieopbouw kon worden gesimuleerd (Fig. 14). De teruggang van de populatiedichtheid blijkt moeilijker te voorspellen door het ontbreken van gegevens over natuurlijke vijanden.Het lijkt waarschijnlijk dat in de toekomst met het model een prognose over de piek van de bladluispopulatie circa 3 weken tevoren mogelijk zal zijn.  相似文献   

15.
Barley yellow dwarf disease is one of the most important problems confronting cereal production in Iran. Barley yellow dwarf virus-PAV (BYDV-PAV) and Cereal yellow dwarf virus-RPV (CYDV-RPV) are the predominant viruses associated with the disease. One isolate of BYDV-PAV from wheat (PAV-IR) and one isolate of CYDV-RPV from barley (RPV-IR) were selected for molecular characterisations. A genome segment of each isolate was amplified by PCR. The PAV-IR fragment (1264 nt) covered a region containing partial genes for coat protein (CP), read through protein (RTP) and movement protein (MP). PAV-IR showed a high sequence identity to PAV isolates from USA, France and Japan (96–97%). In a phylogenetic analysis it was placed into PAV group I together with PAV isolates from barley and oats. The fragment of RPV-IR (719 nt) contained partial genes for CP, RTP and MP. The sequence information confirmed its identity as CYDV. However, RPV-IR showed 90–91% identity with both RPV and Cereal yellow dwarf virus-RPS (CYDV-RPS). Phylogenetic analyses suggested that it was more closely related to RPS. These data comprise the first attempt to characterise BYD-causing viruses in Iran and southwest Asia. The nucleotide sequence data reported appear in the EMBL, GenBank and DDBJ Nucleotide Sequence Databases under the accession numbers AY450425 and AY450454  相似文献   

16.
Broad bean mottle virus (BBMV) was transmitted from infected to healthy faba-bean plants by the curculionid weevilsApion radiolus Kirby,Hypera variabilis Herbst,Pachytychius strumarius Gyll,Smicronyx cyaneus Gyll, andSitona lineatus L. The latter appeared to be an efficient vector: acquisition and inoculation occurred at the first bite, the rate of transmission was c. 41%, and virus retention lasted for at least seven days.S. lineatus transmitted the virus from faba bean to lentil and pea, but not to the three genotypes of chickpea tested. This is the first report on the generaHypera, Pachytychius, andSmicronyx as virus vectors, and onA. radiolus, H. variabilis, P. strumarius, andS. cyaneus as vectors of BBMV.Out of 351 samples of food legumes with symptoms suggestive of virus infection, 16, 11, 19, and 17% of the samples of chickpea, lentil, pea, and common bean, respectively, were found infected when tested for BBMV in DAS-ELISA. This is the first report on the natural occurrence of BBMV in chickpea, lentil, pea, and common bean. The virus should be regarded as a food-legume virus rather than a faba-bean virus solely, and is considered an actual threat to food legume improvement programmes.  相似文献   

17.
Corynebacterium fascians, which causes leafy gall, has been shown to be responsible for the unusual symptoms recently found in lilies. The symptoms are described and the different bacterial isolates compared by biochemical, serological and pathogenicity experiments. No evidence could be found for the existence of specialized strains even though considerable variation in virulence could be demonstrated. Although the role of variation in susceptibility of the different lily cultivars should not be underestimated, it would appear that high inoculum levels ofC. fascians in the soil may be largely responsible for these outbreaks.Also included in this study are the results of biochemical, serological and pathogenicity experiments ofC. fascians which has been isolated fromKalanchoe, Euphorbia, Brodiaea, Hebe andVerbascum.Samenvatting Reeds een aantal jaren was in lelies een woekering in stengelbollen bekend, die echter sporadisch voorkwam en economisch van weinig betekenis was. Tijdens de zomer van 1977 echter trad de ziekte op één enkel perceel zo ernstig op dat zeer aanzienlijke oogstderving het gevolg was. Behalve de stengelbol kan ook de hoofdbol misvormd zijn. Bovendien kunnen misvormde stengelbollen lange spruiten vormen, zgn. sabeltandvorming. Soms is het wortelstelsel gereduceerd; in de kas zijn verdikte stengels waargenomen. De ziekte staat nu bekend onder de naam woekerziekte.Door de PD te Wageningen en het LBO te Lisse werd de bacterieCorynebacterium fascians (Tilford) Dows. uit het zieke materiaal geïsoleerd. In gezamenlijk onderzoek werd nagegaan of de bacterie de veroorzaker is van bovengenoemde symptomen en of hier sprake is van een op lelie gespecialiseerde stam.Biochemische en serologische vergelijkingen tussen isolaten vanC. fascians uit lelie,Kalanchoe, Euphorbia, Brodiaeea, Hebe enVerbascum laten zien dat er zeer weinig verschillen bestaan. Alle isolaten reageren op een standaard antiserum met titers variërend tussen 1: 640–1: 5120.Een oriënterende inoculatieproef werd uitgevoerd op het LBO in 1977. Daarna werden op de PD 10 van de 25 isolaten uit lelie en 8 uit andere waardplanten getoetst op lelie, chrysant en lathyrus. Uit de inoculatieproeven blijkt, dat de bacterie de veroorzaker is van de waargenomen symptomen. Tussen de isolaten blijkt een groot verschil in pathogeniteit te bestaan (12–100% aantasting), zonder dat dit aan herkomst gebonden is. Het voorkomen van op lelie of andere waardplanten gespecialiseerde stammen is daarom niet aan te nemen.In hoeverre de hevige aantasting een gevolg is van een opbouw van de bacterie-populatie door een te nauwe vruchtwisseling en mechanische rooimethoden moet worden nagegaan.  相似文献   

18.
Tsror  Leah  Aharon  M.  Erlich  Orly 《Phytoparasitica》1999,27(3):215-226
Potato seed tubers are imported to Israel from northern Europe and planted in spring; tubers harvested early from the spring crop are used as seed for the autumn crop. Although only seed lots registered as certified are imported, a previous survey (1984–1994) indicated that most imported lots were affected by latent or active infections caused byErwinia carotovora,Streptomyces scabies, Rhizoctonia solani, Fusarium spp. andSpongospora subterranae. The survey was extended until 1998, and included additional pathogens:Ralstonia solanacearum,Helminthosporium solani, Colletotrichum coccodes andVerticillium dahliae. Most of these pathogens were also monitored in domestic seed tubers, and are reported for the first time. Brown rot was not observed in any of the imported lots. Blackleg and soft rot caused byErwinia spp. were detected in most of the imported lots; however, less than 7% of the lots were contaminated at high levels, while approximately 65% were contaminated at moderate levels. Common scab was detected in most of the imported lots; 51% of the imported lots were contaminated at moderate or high levels, whereas only 6.5% of the domestic seed lots were contaminated at these levels. Black scurf was detected in most of the imported lots; on average, 47.3%, 44.2% and 1.4% of the lots were contaminated at low, moderate and high levels, respectively, and only 7.1% were disease-free. In contrast, most of the domestic lots were either disease-free (45.4%) or had a low disease incidence (37.3%). Only 16.7% of the lots were moderately infected and 0.2% were highly contaminated. Silver scurf was observed in most of the imported lots during all years of the survey, with no differences among the producing countries; on average, 22.7%, 66.1% and 7.5% of the lots were contaminated at low, moderate and high levels, respectively, and only 3.7% were disease-free. Most of the domestic lots (76%) were disease-free and only 6.6% were infected at moderate or high levels. Black dot was observed in a considerable portion of the shipments from Holland during all years of the survey, particularly in 1998, when 34% of the lots were infected. The shipments from France and Germany were infected at low levels, except in 1998, when 19% and 11% of the lots, respectively, arrived infected. In shipments from Scotland and Ireland low incidences of the disease were observed in 1994 and 1995. In the domestic lots, black dot incidence was low (<2.4%) except in 1996, when 11% of the lots were infected.V. dahliae was monitored only in domestic seed tubers. The incidence of disease-free lots was 56–64%, whereas in 20–30% of the lots the level of infection was <5%, and in 6–16% of the lots the level was >5%. The survey findings demonstrate transmission of seedborne pathogens; most of these pathogens can become established in the soil and eventually cause severe outbreaks of disease in potatoes grown in Israel. http://www.phytoparasitica.org posting May 16, 1999.  相似文献   

19.
Research on root rot pathogens of peas in the Netherlands has confirmed the prevalence ofFusarium solani, F. oxysporum, Pythium spp.,Mycosphaerella pinodes andPhoma medicaginis var.pinodella. Aphanomyces euteiches andThielaviopsis basicola were identified for the first time as pea pathogens in the Netherlands. Other pathogens such asRhizoctonia solani andCylindrocarpon destructans were also found on diseased parts of roots. F. solani existed in different degrees of pathogenicity, and was sometimes highly specific to pea, dwarf bean of field bean, depending on the cropping history of the field.A. euteiches was specific to peas, whereasT. basicola showed some degree of physiological specialization.  相似文献   

20.
Organic amendments and green manure are potential alternatives to the harmful chemical control means currently used against plant-parasitic nematodes. In this work, Chrysanthemum coronarium was applied to the soil as a green manure to control the root-knot nematodes Meloidogyne incognita and M. javanica. Chrysanthemum coronarium significantly reduced nematode infection of tomato roots and improved plant-top fresh weight, both in the greenhouse and in microplots. Other green manures, derived from Anthemis pseudocotula, wild chickpea (Cicer pinnatifidum), Geranium spp. and wheat, were not as effective as C. coronarium. Chrysanthemum coronarium, retained its nematicidal activity even when applied as a dried material. Only mature C. coronarium plants, in their flowering stage, exhibited nematode control activity, but the green plant parts were more effective than the flowers. An aqueous extract of C. coronarium exhibited in vitro, nematostatic activity towards M. incognita and M. javanica second-stage juveniles and inhibited their hatching from eggs and egg-masses; its nematostatic activity was expressed also against other phytonematode species such as Heterodera avenae and Pratylenchus mediterraneus, but did not affect the beneficial entomopathogenic nematode Steinernema feltiae.  相似文献   

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