朗伍德王莲腐霉叶腐病及病原鉴定

2009年,南京中山植物园王莲育苗池中的朗伍德王莲(Victoria‘Longwood Hybrid’)发生了叶片腐烂病。按照柯赫氏法则对其进行了病原物的分离、纯化和致病性测定,并对菌株进行了形态学和分子生物学鉴定。从发病部位稳定分离到形态一致的低等真菌;致病性测定结果表明,回接后发病株产生与自然侵染相同的症状,并重新分离到相同菌株。通过病原菌形态特征和核糖体rDNA ITS序列分析,病株分离物被鉴定为旋柄腐霉(Pythium helicoides)。这是国内外首次报道在王莲上分离出旋柄腐霉并证明其为王莲的致病菌。该病害被定名为王莲腐霉叶腐病。     

小麦细菌性叶鞘褐腐病及其病原鉴定

为搞清杭州小麦上一新发生病害的病原，从病区获得6份小麦病株样本的症状，经初步的植物细菌学特性分析，鉴定为细菌病害。6个分离细菌经32项生理生化反应、茵落形态、致病性、Biolog、脂肪酸分析及与6个标准菌株比较，证实了这种小麦叶鞘褐腐病是由Pseudomonasfuscovaginae．,Miyajima，Tanii＆Akita引起，与水稻细菌性叶鞘褐腐病为同一病原。     

福建省西番莲茎基腐病病原鉴定

 西番莲(Passiflora edulis sims)是近年新兴的饮料水果,目前在福建省已栽培万余亩。1988~1990年作者调查了福建省8个市县的西番莲产区,发现茎基腐病普遍发生.严重的造成果园毁种无收。     

人参褐腐病病原菌的鉴定

吉林省是我国人参重要的生产基地,人参根部病害直接影响人参的产量和商品价值。从1985年以来,开展了人参病害调查研究工作。作者在抚松、浑江、辉南和桦甸地区的人参上发现一种与已记载人参根病症状不同的病害,该病害造成人参根呈褐色软腐,田间主要为害5—6年生的参根,一般发病率为3％～5％,严重田块发病率可达10％以上。为此,对这个病害的病原菌进行了研究。     

枣铁皮病病原鉴定

 枣铁皮病主要为害大枣果实,可导致果实腐烂和提早落果,据症状特点可分为铁皮型和缩果型2种类型。1993~1995年对河北和河南2省6个不同枣区大枣铁皮病病果进行分离、接种和再分离,证实枣铁皮病病原为:链格孢Alternaria alternata(Fr.) Keissler;实腐茎点霉Phoma destructiva Plowr,壳梭孢属一种真菌Fusicoccum sp.3种病原真菌可以单独或混合侵染。     

莱芜生姜茎腐病的病原鉴定

利用组织分离技术和菌丝尖端纯化技术对莱芜地区生姜茎腐病的病原菌进行了分离和纯化.并按照柯赫法则,利用真菌形态学鉴定方法对病原菌进行了鉴定.结果表明,引起山东莱芜生姜产区的生姜茎腐病的病原菌为群结腐霉(Pythium myriotylum Drechsler).     

大白菜对褐腐病抗性的快速鉴定方法研究

为了建立一套大白菜对褐腐病抗性的快速鉴定方法,本研究对菌丝、菌核作为接种物进行了比较,并分析了菌丝浓度、接种苗龄、接种温度以及接种后空气湿度对褐腐病发病的影响。结果表明：菌饼回接土壤表面为最佳接种方法,菌丝浓度对致病力无影响;最佳接种苗龄为1~2叶期,最佳接种温度25?℃,最佳接种湿度90%~100%;病情指数调查均在接种后第7天。     

津黑两地大白菜褐腐病病原菌鉴定及生物学特性的比较

采用形态特征观察、致病性测定及rDNA-ITS序列分析等方法对天津、黑龙江两地大白菜褐腐病的病原菌进行鉴定。结果表明,天津、黑龙江两地大白菜褐腐病的病原菌为立枯丝核菌(Rhizoctonia solani Kühn),分离鉴定出TJ和DB两个菌株,分属立枯丝核菌AG-2融合群和AG-1融合群;DB菌株为一新菌株。两菌株菌丝生长最适温度均为25℃,最适pH为7,最适光照为12h。DB菌株菌丝生长速率快于TJ菌株;但TJ菌株先于DB菌株形成菌核,且形成量多。两菌株在碳源、氮源利用和菌核致死温度上也存在差异。     

小麦镰刀菌根腐病病原鉴定及其防治

1973年我省小麦发生一种新病害,该病麦苗不表现症状,但到开花前后麦株突然青枯死亡,减产30一80％,重则颗粒无收。患病植株基部发黑随同根系腐烂,自1983—1987年,作者从病田广泛采集标本进行病原分离培养获得3种镰刀菌(Fusarium Spp),经接种试验,证明该病是由一种黄色镰刀菌F.culmorum引起的,用麦粒培养能大量形成镰刀形分生孢子,但在PDA培养基或病株上不形成、黄色镰刀菌以菌丝在病基部扩展蔓延、引起基部组织腐烂,并形成小孢子在田间越夏,以后随田间耕作,腐烂组织破碎,小孢子随之扩散土中,当冬季小麦播种后,小孢子萌发侵入麦苗基部以菌丝潜伏越冬,到开花期引起小麦死亡。 通过与油菜等十字花科作物一年轮作、药剂拌种、木霉生物防治等措施均有防病增产效果。     

枇杷花腐病病原物的初步鉴定

经调查发现,在重庆发生的枇杷花腐病症状有2种类型:干腐型和湿腐型。通过病原菌形态特征、培养性状和致病性测定,初步鉴定这两种症状分别由拟盘多毛孢菌[Pestalotiopsis eriobotrifolia(Guba)Chen et Cao]和灰葡萄孢菌(Botrytis cinerea Pers.)引起。枇杷花腐病害的发生与环境湿度有关,且湿度越大,病害发生越严重。     

国内一种果树新病害--石榴枯萎病

2001年在云南省蒙自县相继发生石榴枯萎病，经作者分离鉴定以及致病性测定，证明病害是由甘薯长喙壳Ceratocystis fimbriata Ellis and Halsted引起的，为国内果树新病害。对病害的症状、鉴定方法、病原菌形态及发生危害情况进行了描述。     

国内一种玉米新病害--玉米黑腐病

1999年7月云南省元谋县城郊玉米地发现一种玉米新病害,发病面积大约70hm2.其典型症状表现为植株矮化,节间缩短,叶片密集簇生,叶片上有黄绿相间的条斑.叶鞘上有坏死或腐烂病斑,幼穗腐烂,不实,严重者绝产,颗粒无收.从坏死或腐烂的叶鞘和果穗上可镜检到分生孢子及分生孢子梗.纯化培养后,并按柯赫氏法则进行接种试验,病原鉴定为柔弱无枝孢Acladium tenellum(Berk.& Curt.)Subram.comb.nov..本文对病害症状、病原形态、发病情况等进行了详细研究,确定该病为玉米一种新病害.     

我国甘薯新病害-茎腐病的研究初报

 2006年以来广东省主要甘薯产区发现1种甘薯新病害,主要症状表现为叶片变黄,茎基部呈黑色水浸状腐烂,并逐渐沿茎枝向顶端腐烂,后整株倒伏、死亡。从甘薯病茎部分离得到了病菌,经柯赫法则验证为致病病原菌。根据病原菌的形态特征、培养性状、生理生化及16S rDNA序列分析,鉴定其为菊欧文氏菌(Erwinia chrysanthemi)。采用茎枝、菌液共培养法接种8个甘薯品种,结果表明8个品种均无抗病性,病原菌致病性较强。这是我国首次发现该病害。      

青海省栽培秦艽新病害——锈病

秦艽,别名牛尾艽,为龙胆科,龙胆属高山药用植物,自然分布于海拔2 400～3 500m,气候冷凉、日照充足地区,青海适应其生长,分布较广.随着农业产业结构的调整和退耕还林(草)政策的实施,青海省中、藏药种植面积逐年扩大,已成为青海省的优势产业.秦艽因其主治风湿脾痛、筋脉拘挛、骨节酸痛、小儿疳积和发热疾病,种植和开发前景较好.     

Appearance of a new leaf rot disease on common ice plant

An unknown disease abruptly appeared on hydroponic cultures of common ice plant (Mesembryanthemum crystallinum) in the greenhouse, causing catastrophic damage. Although the symptoms of the plant were unlike typical Botrytis lesions on leaves and stems of other plants, fungi isolated from the necrotic lesions on the plant were similar to genus Botrytis in terms of conidial shape, colony color and nature. A representative isolate, Ice-2, caused similar symptoms on the host plants after inoculation with conidia, and the same fungus was isolated from the lesions. The conidia and conidiophores of Ice-2 were morphologically similar to those of B. cinerea but not to those of B. allii, B. fabae or B. squamosa. The tested Botrytis fungi grew at temperatures between 5 and 30°C. Ice-2 grew faster than the others at the lower end of the temperature range. Ice-2 was also more virulent than B. cinerea (Bay-1) in artificial inoculations, especially on common ice plant leaves. The glyceraldehyde-3-phosphate dehydrogenase gene (G3PDH) sequence of Ice-2 was determined and compared with those from four Botrytis species. The gene sequence of Ice-2 appeared to be identical to that of B. cinerea. In leaf tests on common ice plant and kidney bean, the diseases caused by Ice-2 and Bay-1 were controlled equally well by the primary Botrytis fungicides. Based on the results of the present studies, Ice-2 is thought to be Botrytis cinerea Person: Fries.     

中国蔷薇科归化植物新纪录——尖齿黑莓

安徽省滁州市发现中国蔷薇科新记录植物——尖齿黑莓(Rubus argutus Link).该种原产北美洲,是许多栽培树莓的亲本,目前已在日本、新西兰、夏威夷等地归化,并造成一定的生态危害.尖齿黑莓具有掌状复叶、茎具棱、皮刺极为发达,易与国产悬钩子属植物显著区别.文章调查了其分布面积、提供详细的照片与形态描述,介绍了其生...     

Thecaphora dahuangis,a new species causing leaf smut disease of the traditional medicinal plant dahuang (Rheum palmatum) in China

Chinese rhubarb (Rheum palmatum) is an important crop that has been used in traditional Chinese medicine for over 2,000 years. The main cultivation areas are the Chinese provinces of Gansu, Qinhai, Tibet, and Sichuan. Various fungal diseases threaten Chinese rhubarb, the most common of which is leaf smut. In literature, the causal agent of this disease is described as Thecaphora schwarzmaniana. We present morphological data and molecular phylogenetic data of two rDNA loci (ITS1-5.8S-ITS2 and 28S D1-D2) that justify the classification of the causal agent as a distinct species. Here we describe the new species Thecaphora dahuangis for the leaf smut pathogen of Chinese rhubarb.     

胡萝卜新病害——胡萝卜斑枯病

胡萝卜是人们喜欢食用的蔬菜,在甘肃河西走廊各市、县都有种植,一般春季套种,秋季复种,年栽培面积8 000hm2以上.秋季栽培的胡萝卜9月中旬开始发病,下旬发病高峰,全田叶片枯黄,火烧状,田间发病率达56%,严重田块100%,减产20%～30%;贮藏期先根头腐烂,渐向根部发展,造成烂窖.经鉴定引起该病的病原菌为半知菌亚门,腔孢纲Coelomycetes,胡萝卜类腊肠茎点霉Allantophomoidescarotae S.L.Wei et T.Y.Zhang(<菌物系统>2003第1期),根据其症状特点,定名为胡萝卜斑枯病.     

A polyetic modelling framework for plant disease emergence

Plant disease emergences have dramatically increased recently as a result of global changes, especially with respect to trade, host genetic uniformity, and climate change. A better understanding of the conditions and processes determining epidemic outbreaks caused by the emergence of a new pathogen, or pathogen strain, is needed to develop strategies and inform decisions to manage emerging diseases. A polyetic process-based model is developed to analyse conditions of disease emergence. This model simulates polycyclic epidemics during successive growing seasons, the yield losses they cause, and the pathogen survival between growing seasons. This framework considers one immigrant strain coming in a single event into a system where a resident strain is already established. Outcomes are formulated as probability of emergence, time to emergence, and yield loss, resulting from deterministic and stochastic simulations. An analytical solution to determine a threshold for emergence is also derived. Analyses focus on the effects of two fitness parameters on emergence: the relative rate of reproduction (epidemic speed), and the relative rate of mortality (decay of population between seasons). Analyses revealed that stochasticity is a critical feature of disease emergence. The simulations suggest that: (a) emergence may require a series of independent immigration events before a successful invasion takes place; (b) an explosion in the population size of the new pathogen (or strain) may be preceded by many successive growing seasons of cryptic presence following an immigration event; and (c) survival between growing seasons is as important as reproduction during the growing season in determining disease emergence.