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1.
Root and crown rot of raspberry (Rubus idaeus L.) was observed in a plantation at the experimental station of small fruits in Kostinbrod, Bulgaria. Isolates ofPhytophthora spp. were obtained from diseased plants. Colony morphology, growth rates, features of asexual and sexual structures were studied and as a result twoPhytophthora species were identified:Phytophthora citricola Saw. andPhytophora citrophthora (R.E. Sm. & E.H. Sm.) Leonian. Their pathogenicity was confirmed in artificial inoculation experiments. The isozyme (-esterase) patterns ofP. citrophthora andP. citricola isolates from raspberry and from the collection of the CBS, Baarn the Netherlands were compared, using micro-gel electrophoresis. Both species are reported for the first time as pathogens of raspberry in Bulgaria. This is only the second report in phytopathological literature ofP. citrophthora on raspberry, the first being from Chile [Latorre and Munoz, 1993].  相似文献   

2.
Fifty-five isolates of Rosellinia necatrix, the cause of common avocado white root rot disease, were collected from south-east Spain and characterised according to their virulence behaviour and their molecular patterns to assess broader levels of genetic diversity. Virulence properties were revealed by in vitro inoculation on avocado plants. Differences in reaction types showed variability among these isolates. No sequence differences were observed when the internal transcribed spacer 1 (ITS1) and ITS2 regions and DNA fragments of the β-tubulin, adenosine triphosphatase and translation elongation factor 1 genes were explored in representive isolates from five virulence groups. Random amplified polymorphic DNA (RAPD) amplifications were also performed for each isolate using 19 random primers. Four of these primers revealed polymorphism among isolates and repetitive and discriminative bands were used to build an unweighted pair group with arithmetic mean tree. However, RAPD clustering showed low stability, and no correlation between RAPD and virulence groups was observed, possibly indicating high levels of sexual recombination.  相似文献   

3.
Avocado root rot is the most important disease of this fruit crop worldwide. This pathology may be caused by several biotic and abiotic agents, with the oomycete Phytophthora cinnamomi being the pathogen more frequently associated with poor phytosanitary conditions. There are disease control methods available that can reduce disease severity and allow plants to recover; however, they are not consistently and promptly applied. In addition, only chemical products are used by farmers as the preferred management method. This research aimed to evaluate different root rot management strategies in a commercial orchard. Data suggest that individual control methods are not as effective as when they are applied in combination, as in the T8 treatment (metalaxyl + mancozeb applied in drench; injection of potassium phosphite to each plant stem; potassium silicate applied in drench; addition of a layer of organic mulch and incorporation of 10 kg of composted substrate, both applied to the ground around the base of each tree). Using this strategy, the area under the disease progress curve for the avocado root rot was reduced by up to 68.6%, and the extra‐quality avocado fruit class increased by as much as 44% compared to the diseased control plants (T0) (P < 0.01). With the combined treatment T8, farm income showed a 9.5‐fold increase, probably due to an increase in the percentage of viable roots by up to 9.4‐fold, which would have improved nutrient and water uptake.  相似文献   

4.
Phytophthora root rot of sweet pepper   总被引:1,自引:0,他引:1  
Phytophthora capsici proved to be the causal agent of a root and crown rot of sweet pepper in the Netherlands.P. capsici was pathogenic on sweet pepper, tomato and sometimes on eggplant but not on tobacco Xanthi. Of these test plants only tomato was infected byP. nicotianae.No different symptoms in plants infected with eitherP. capsici orP. nicotianae were found. Dipping the roots of tomato and sweet pepper plants in a suspension ofP. capsici resulted in a more severe attack than pouring the suspension on the stem base.Resistance in tomato toP. nicotianae did not include resistance toP. capsici. A method to distinguishP. capsici fromP. nicotianae after isolation from soil is described. Both species were able to infect green fruits of tomato and sweet pepper.p. capsici survived in moist soil in the absence of a host for at least 15 months.Samenvatting Phytophthora capsici bleek de oorzaak te zijn van een voet-en wortelrot in paprika op twee bedrijven in 1977 in Nederland.P. capsici was pathogeen op paprika, tomaat en soms op aubergine maar niet op tabak Xanthi.P. nicotianae tastte van deze toetsplanten alleen tomaat aan. Verschillen in symptomen tussenP. nicotianae enP. capsici werden bij tomaat niet waargenomen.Het dompelen van de wortels in eenP. capsici suspensie gaf een ernstiger aantasting dan het begieten van de wortelhals met deze suspensie.Resistentie in tomaat tegenP. nicotianae bleek geen resistentie tegenP. capsici in te houden. P. capsici kan in grond worden aangetoond door groene paprikavruchten als vangsubstraat te gebruiken.P. capsici enP. nicotianae kunnen beide zowel vruchten van tomaat als paprika aantasten. P. capsici overleefde een periode van 15 maan den in vochtige grond waarop geen waardplant werd geteeld.  相似文献   

5.
A boll rot of cotton (Gossypium hirsutum L.) was observed for the first time in Greece in August 1993 in Larissa and Volos counties, and in August and September 1995 in Trikala and Phthiotis counties. Fungi of the genusPhytophthora were isolated from diseased plants. Morphological characteristics of the pathogen were recorded on mounts made directly from the infected tissues or after growth of the isolated fungus on corn meal agar or sterile distilled water. Colony morphology, growth rates, features of asexual and sexual structures and maximum growth temperatures were examined. APhytophthora species new to Europe,Phytophthora boehmeriae Sawada, attacking cotton bolls, was identified. The pathogenicity of the isolates was confirmed by artificial inoculations of detached cotton bolls. Analysis of α-esterase isozymes revealed unique banding patterns for isolates ofP. boehmeriae compared with those ofP. cactorum andP. parasitica, which arePhytophthora species with similar morphology.  相似文献   

6.
为评价东北地区玉米主推品种对禾谷镰孢根腐病的抗性水平,探究根腐病发生与苗势、产量损失间的关系,采用人工接种方法鉴定东北地区117个玉米主推品种对禾谷镰孢根腐病的抗性水平,应用室内盆栽试验分析自交系LN810在施用氮、磷、钾及复合肥后对禾谷镰孢根腐病发生和苗势的影响,在田间对先玉335接种禾谷镰孢菌Fusarium graminearum后探究根腐病发生程度对其苗势及产量的影响。结果显示,117个玉米品种对禾谷镰孢根腐病的抗性差异明显,鉴定出高抗品种14个,抗病品种44个,中抗品种47个,感病品种12个,其中表现中抗以上的品种占89.74%,且中早熟材料均表现为抗性。与未施肥相比,施用磷钾肥后玉米禾谷镰孢根腐病发生率最低,为22.03%。按照禾谷镰孢根腐病发生程度从轻到重将先玉335群体划分为一、二、三类苗,级别越高苗势越弱,产量测定发现二、三类苗的平均产量较一类苗的平均产量分别下降了39.97%和76.39%。表明东北地区主推玉米品种大部分对禾谷镰孢根腐病表现出抗性,但仍有部分品种存在较大感病风险,且该病害的发生程度与幼苗长势和产量呈负相关,施用磷钾肥可降低该病害的发生率。  相似文献   

7.
为探明黄瓜嫁接栽培与木霉菌使用提高黄瓜幼苗抗根腐病的能力及生理调节的差异,利用哈茨木霉菌DQ002和根腐病病原菌孢子悬浮液对黄瓜直根苗根部接种与根腐病病原菌孢子悬浮液对黄瓜嫁接苗进行根部接种处理,测定黄瓜直根苗和黄瓜嫁接苗病害发生率及根系生理变化。结果表明:哈茨木霉菌DQ002通过激发黄瓜直根苗根系中POD、PPO、SOD活性而抑制了H2O2积累和O-2的产生速率,并促进了黄瓜直根苗根系PAL、几丁质酶、β-1,3-葡聚糖酶活性以及类黄酮含量升高,提高了抗病性;接种根腐病菌,黄瓜嫁接(T2)提高了根系中POD活性、培养前期PPO活性及培养后期SOD的活性,降低了H2O2的积累和O-2产生速率,促进了PAL、几丁质酶及培养后期的β-1,3-葡聚糖酶活性,但H2O2的积累和O-2产生速率显著高于哈茨木霉菌DQ002处理的黄瓜直根苗,而PAL、几丁质酶、β-1,3-葡聚糖酶活性以及类黄酮含量明显低于木霉菌处理的直根苗;T3(先接种病原菌后接种木霉菌)和T4(先接种木霉菌后接种病原菌)处理的黄瓜直根苗根腐病的发病率分别为22.39%和17.87%,病情指数分别为23.03%和14.33%,明显低于CK1(清水处理直根苗)和T1(单独病原菌处理直根苗)处理的发病率(35.82%和57.39%)和病情指数(37.10%和46.97%),以及黄瓜嫁接苗(T2)的发病率(42.90%)和病情指数(40.47%),但哈茨木霉菌使用时间不同则效果有异。黄瓜嫁接和哈茨木霉菌DQ002处理直根苗能提高黄瓜苗对根腐病的抗性,但是二者对黄瓜苗根系生理的调节作用存在差异,可能是导致根腐病发生存在差异的生理原因之一。  相似文献   

8.
山西省蒙古黄芪根腐病优势致病菌群分析   总被引:6,自引:3,他引:6  
为明确山西省蒙古黄芪根腐病的优势致病菌群及其分布区域和症状差异性,采用组织分离法分离获得致病菌,按柯赫氏法则回接验证,结合形态学特征与EF-1α基因分子鉴定结果明确其分类地位,并分析不同地域和不同发病症状下致病菌的分离频率。结果表明,引起山西省蒙古黄芪根腐病的致病菌包括锐顶镰刀菌Fusarium acuminatum、腐皮镰刀菌F.solani、尖孢镰刀菌F.oxysporum、芬芳镰刀菌F.redolens、链格孢菌Alternaria sp.以及Ilyonectria torresensis,其中锐顶镰刀菌和腐皮镰刀菌为优势致病菌,平均分离频率为53.83%和26.42%。不同地区根腐病的优势致病菌具有明显差异,浑源县和应县为锐顶镰刀菌、腐皮镰刀菌,分离频率分别是42.86%、39.13%和62.50%、37.50%;五寨县为锐顶镰刀菌和尖孢镰刀菌,分离频率56.14%和35.96%。根腐病的症状具有一定地域差异,且引发不同症状的优势致病菌也不同,总体上引起纤维状腐烂的优势致病菌为锐顶镰刀菌、腐皮镰刀菌和尖孢镰刀菌,前二者平均分离频率分别为63.37%和20.50%,尖孢镰刀菌仅在五寨县检出,分离频率为21.98%;引起侧根发黑的优势致病菌主要是锐顶镰刀菌和腐皮镰刀菌,平均分离频率分别为35.50%和21.65%,但在浑源县未发现此类症状;引起皱缩软根的优势致病菌在各地差异明显,五寨县以尖孢镰刀菌最占优势,分离频率为43.48%,浑源县为链格孢菌,分离频率为32.79%,应县则是腐皮镰刀菌,分离频率为60.00%。  相似文献   

9.
The capacity of several strains of root-colonizing bacteria to suppressPythium aphanidermatum, Pythium dissotocum and root rot was investigated in chrysanthemums grown in single-plant hydroponic units containing an aerated nutrient solution. The strains were applied in the nutrient solution at a final density of 104 CFU ml−1 and 14 days later the root systems were inoculated withPythium by immersion in suspensions of 104 zoospores ml−1 solution. Controls received no bacteria, noPythium, or one of thePythium spp. but no bacteria. Strain effectiveness was estimated based on percent roots colonized byPythium and area under disease progress curves (AUDPC). In plants treated respectively withPseudomonas (Ps.)chlororaphis 63-28 andBacillus cereus HY06 and inoculated withP. aphanidermatum, root colonization by the pathogen was 83% and 72% lower than in the pathogen control, and AUDPC values were reduced by 61% and 65%. ForP. dissotocum, the respective strains reduced root colonization by 87% and 91%, and AUDPC values by 70% and 90%. In plants treated respectively withPs. chlororaphis Tx-1 andComamonas acidovorans C-4-7-28, root colonization byP. aphanidermatum was 84% and 80% lower than in the controls and AUDPC values were reduced by 66% and 57%; these strains did not suppressP. dissotocum. Burkholderia gladioli C-2-74 andC. acidovorans OCR-7-8-38, respectively, suppressed colonization of roots byP. dissotocum by 74% and 86%, and reduced AUDPC values by 60% and 70%, but were ineffective againstP. aphanidermatum. C. acidovorans OCR-7-8-39 reduced colonization and AUDPC values ofP. aphanidermatum by 57% and 42%, respectively.Pseudomonas corrugata 13,Ps. fluorescens 15 and JZ12, and three additional strains ofC. acidovorans were weakly or nonsuppressive againstP. aphanidermatum. Strains that reduced AUDPC values forP. aphanidermatum orP. dissotocum when applied at 104 CFU ml−1 were 11%–39% less effective at 103 CFU ml−1. Four tested strains (Ps. chlororaphis 63-28,Ps. chlororaphis Tx-1,B. cereus HY06, andB. gladioli C-7-24) in most instances suppressed root colonization and lowered AUDPC values ofP. aphanidermatum when applied at 14, 7 or 0 days before inoculation, but reduction of the respective variables was generally greater when the strains were applied at 14 days (63%–87% and 75%–78%) or 7 days (44%–47% and 31%–88%) than at 0 days (14%–31% and 23%–62%) before inoculation.Ps. chlororaphis Tx-1,Ps. chlororaphis 63-28 andB. cereus HY06 significantly suppressedP. aphanidermatum whether the temperature of the nutrient solution was high (32°C) or moderate (24°C). Taken together, the observations suggest thatPs. chlororaphis 63-28,B. cereus HY06,Ps. chlororaphis Tx-1,B. gladioli C-2-74 andC. acidovorans OCR-7-8-38 have the potential for controlling Pythium root rot in hydroponic chrysanthemums. http://www.phytoparasitica.org posting Jan. 24, 2007.  相似文献   

10.
Since 1987, Phytophthora root and stem rot of soybean [Glycine max (L.) Merr. cv. Tanbakuro], caused by Phytophthora sojae Kaufman and Gerdemann, has been increasing in the Sasayama, Nishiwaki, and Kasai regions in Hyogo, the most famous soybean (cv. Tanbakuro)-producing areas in Japan. In 2002 to 2004, 51 isolates (one from each field) of P. sojae were recovered from 51 fields in Hyogo. These isolates were tested for virulence on six Japanese differential soybean cultivars used for race determination in Japan, and three additional ones containing four Rps genes used in Indiana, USA. Race E was the most prevalent from 2002 to 2004, followed by races A, C, D, and four new races (proposed as races K, L, M, and N). Interestingly, none of the new races had high virulence on the Japanese differential cultivars, compared with other races in each area. One (race N) was avirulent on all six soybean differentials. There was a difference in race distribution on each of three individual areas; race E seemed to be a major component of the P. sojae population in Sasayama, whereas race A and the new race M were the most prevalent in Nishiwaki and Kasai, respectively. Rps6 (cv. Altona) and Rps1a + Rps7 (cv. Harosoy 63) were infected by 90.2% and 33.3% of all isolates, respectively. However, Rps1d (cv. PI103091) was not susceptible to any of the 51 isolates, nor was cv. Gedenshirazu-1. These two soybean cultivars were considered to be potential sources of resistance to breed new resistant cultivars with the desirable characteristics of cv. Tanbakuro for this region.  相似文献   

11.
在黑龙江省佳木斯市合江地区农科所发现一种小豆疫霉茎腐病,典型症状是在茎部产生红棕色病斑,有时可在病茎和病荚产生白色霉层,严重时发病植株萎蔫、死亡.病原菌游动孢子囊卵圆形至倒梨形,无乳突,在孢囊柄上不脱落,平均大小为47μm×30μm,长宽比为1.6∶1.有性生殖为同宗配合,藏卵器圆形,平均直径为36.8μm,卵孢子平均直径为29.7μm,平均壁厚为2.9μm;雄器球形至卵圆形,围生,平均大小为16.4μm×15.7μm.生长温度为9~37℃,最适生长温度为24~27℃,生长抑制温度为39℃.完全抑制菌丝生长的孔雀绿浓度为5μg/ml,恶霉灵浓度为100μg/ml时对菌丝的生长相对抑制率为20%.病原菌无伤接种时只侵染小豆,伤口接种对绿豆、豇豆和菜豆具有不同程度的致病性.根据形态、生理、寄主范围和病害症状,病原菌被鉴定为豇豆疫霉菌小豆专化型(Phytophthora vignae f. sp. adzukcola).对70份小豆资源的抗性进行了室内接种评价,有7份资源表现抗病.  相似文献   

12.
山东省小麦根腐病病原菌的分离鉴定   总被引:5,自引:3,他引:5  
为明确山东省小麦根腐病的病原菌种类,于2012—2014年从山东省10个地市采集小麦病株,通过组织分离法获得了185株分离物,利用形态学鉴定方法,结合基于5.8S r DNA-ITS序列或TEF-1α基因序列分析的分子鉴定方法对分离物进行了鉴定。结果表明:分离物中共得到135株麦根腐平脐蠕孢Bipolaris sorokiniana,占分离病原菌总数的72.97%,属优势种群;50株镰孢属Fusarium菌株,其中14株尖孢镰孢菌Fusarium oxysporum、19株层出镰孢菌Fusarium proliferatum和17株黄色镰孢菌Fusarium culmorum;按照柯赫氏法则进行致病性测定,证实了4种病原菌对鲁麦21号具有致病性,麦根腐平脐蠕孢的致病力较强,病情指数显著高于镰孢菌属真菌。研究表明,山东小麦根腐病主要是由麦根腐平脐蠕孢和镰孢属真菌侵染引起的,麦根腐平脐蠕孢为优势菌群。  相似文献   

13.
青海省青稞根腐病调查及病原菌鉴定   总被引:2,自引:0,他引:2  
为明确青海省青稞根腐病发生情况及其病原菌,于2016年6—9月对青海省海北藏族自治州海晏县、刚察县,海东市互助土族自治县苗期及成株期青稞上根腐病发生情况进行调查,采集19份根腐病样品,采用常规组织分离法对样品进行分离,并对分离菌株进行致病性测定,通过形态学特征及分子生物学方法对其进行鉴定。结果显示,青海省青稞根腐病分布广泛,发病率较高,为10%~20%;发病植株长势弱、发黄,茎基部缢缩腐烂,穗白粒瘪,茎秆发褐或黑红;19份样品中共分离纯化得到93株病原菌菌株,其中73株为燕麦镰孢Fusarium avenaceum,9株为木贼镰孢F. equiseti,11株为锐顶镰孢F. acuminatum;木贼镰孢的绝对病情指数最强,为79.43,燕麦镰孢次之,为50.90,锐顶镰孢最弱,为23.70,各病原种间及种内致病性差异显著。根据分离率及各病原菌致病性综合确定燕麦镰孢为青海省青稞根腐病的优势病原菌。  相似文献   

14.
为了针对根腐病实施有效的生物防治,分离鉴定枸杞根腐病病原菌及其拮抗菌,采用组织分离法获得腐根上的病原菌,结合形态学与分子生物学特征鉴定病原菌;利用稀释涂布、滤纸片法和共培养法从健康根际土壤筛选拮抗细菌,通过形态学观察、生理生化鉴定和16S rDNA序列分析对拮抗效果较好的菌株进行鉴定。结果表明:从枸杞根腐病分离得到腐皮镰刀菌(Fusarium solani)和尖孢镰刀菌(Fusarium oxysporum)两种主要致病菌,从健康枸杞根际土壤中分离获得12株对两种镰刀菌具有拮抗作用的细菌,其中J7-3、J7-8、J7-9和J10-8对腐皮镰刀菌的抑菌率均在80%以上,J7-3和J10-8对尖孢镰刀菌的抑菌率均在70%以上。菌株J7-3和J10-8对根腐病病原菌的抑菌作用较好,分别鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)和枯草芽孢杆菌(Bacillus subtilis),其中J10-8的拮抗作用和溶菌效果最好,可作为研发微生物菌剂的菌种资源。  相似文献   

15.
对10个引起大豆根腐病的真菌分离物进行鉴定。结果表明,这些分离物形态学上与大豆拟茎点种腐病菌相似。用ITS通用引物进行PCR扩增,该菌株与拟茎点种腐病菌MP4PL11PS(GenBank登录号HQ130441.1)同源性达98%。因此,确定该菌株为大豆拟茎点种腐病菌。  相似文献   

16.
Sequences of the internal transcribed spacer (ITS) region 1 were used to examine the phylogenetic relationships among races of 19 isolates of Phytophthora vignae f. sp. adzukicola and between this forma specialis and three isolates of the closely related P. vignae f. sp. vignae. The ITS 1 sequences were highly conserved (> 98.7% similarity) among representatives of both formae speciales groups. The results of this study indicate that P. vignae is a monophyletic group. The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession nos. AB120062–AB120080 and AB120122  相似文献   

17.
A severe crown rot of pear trees of cultivar ‘Kondoula’ grafted on quince rootstock was observed in Greece. Isolations from the affected tissues repeatadly yielded aPhytophthora sp. that was determined by morphological and physiological characteristics to beP. citrophthora. The pathogenicity of two of theP. citrophthora isolates was tested by inoculating trunks of 2-year-old pear trees by mycelial agar disks. Thirty-two days after inoculation all inoculated trees were infected. Although the pear isolates could not be differentiated from isolates ofP. palmivora orP. nicotianae based on isozyme profiles of α-esterase or lactate dehydrogenase, RAPD profiles with one selected primer differentiated the pear isolates from the other species and revealed an electrophoretic banding pattern similar to that of aP. citrophthora standard. This is the first report ofP. citrophthora on pear trees in Greece.  相似文献   

18.
 利用平板对峙法从山东寿光采集的土样中筛选出1株对番茄疫霉根腐病菌Phytophthora capsici Leonian具有较好拮抗作用的生防菌株ZF50,抑菌率为76.26%。经形态学、生理生化特性以及系统发育树分析,确定菌株ZF50为贝莱斯芽胞杆菌Bacillus velezensis。该菌株具有较广谱的抑菌能力,且在活体盆栽和田间小区条件下,将浓度为1×108 cfu·mL-1 ZF50菌悬液10 mL灌根后,对番茄疫霉根腐病的防治效果最好,盆栽防效为55.55%,田间小区防效为43.52%;且该菌株还具有明显的促生效果和产吲哚乙酸的能力。  相似文献   

19.
我国对草莓炭疽根腐病的重视程度亟待提高   总被引:5,自引:0,他引:5  
张国珍 《植物保护》2015,41(2):234-236
草莓炭疽根腐病是近年来发生较为普遍和严重的草莓病害,但对该病害的认识不足甚至存在误区。本文介绍了草莓炭疽根腐病与草莓红中柱根腐病在症状表现、病原菌种类及用药策略上的不同,并指出了国内草莓炭疽病发生和危害的特点,勿将炭疽根腐病误认为是红中柱根腐病。  相似文献   

20.
A biocontrol agent (Pseudomonas fluorescens) and a phytostimulator (Rhizobium) have been shown to have beneficial effects on plant growth and health. The study of plants inoculated withPseudomonas andRhizobium requires special attention because of the possibility that these agents may influence each other. Our study was conducted to test the effect of these inoculants on co-inoculation in peanut to control root rot, a severe soilborne disease caused byMacrophomina phaseolina. One fluorescent pseudomonad strain, Pf 1, which effectively inhibited the mycelial growth ofM. phaseolina underin vitro conditions, was studied for its compatibility with the biofertilizer bacterial strainRhizobium TNAU 14. Dual culture and colorimetric studies indicated the existence of a positive interaction between the microbial inoculants. However, glasshouse and field studies showed seed treatment and soil application ofPseudomonas fluorescens Pf 1 to be the most effective treatment in reducing root rot incidence and improving the crop vigor index, in comparison with treatments in which both inoculants were applied. http://www.phytoparasitica.org posting Feb. 11, 2002.  相似文献   

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