西瓜枯萎病的发生与防治

西瓜枯萎病又称萎蔫病、蔓割病 ,在我国西瓜产区都有发生 ,近几年来已成为永定县西瓜产地普遍发生的一种重要病害 ,严重影响西瓜的高产、稳产和高效益。 2 0 0 1年和 2 0 0 2年永定县下洋、古竹、湖坑等地春西瓜枯萎病大发生 ,特别是连作地造成大面积减产甚至绝产 ,损失惨重。为了继续抓西瓜生产 ,做好防病工作 ,现将该病的田间症状、发生流行规律及防治方法作如下介绍 ,供广大农民参考。1　田间症状枯萎病主要发生在成株期 ,典型症状是萎蔫。初期病株表现为叶片从下向上逐渐萎蔫 ,似缺水状 ,中午尤为明显 ,早晚尚能恢复 ,数日后不再恢复常…     

西瓜枯萎病发生危害与综合防治

西瓜枯萎病是西瓜生产上的一种毁灭性病害。病菌的厚垣孢子在土壤中可存活 10年之久。病菌从根系侵入 ,引起维管束变褐溃烂 ,导致瓜秧枯死。特别是近年来 ,随着市场对西瓜需求量的增长 ,西瓜种植面积逐年扩大 ,传统的轮作防病措施难以实行 ,导致西瓜枯萎病日趋严重。据京郊调查 ,一般病株率在10 %～ 2 0 % ,重者达 80 %～ 90 % ,重茬地甚至造成绝产。因此 ,深入研究西瓜枯萎病的发生规律及有效防治方法 ,已成为当前生产上急待解决的重要问题。现将我们近年在京郊大兴、通州、顺义等地对西瓜枯萎病的发生规律及综防技术研究结果简报如下。1　…     

石榴常见害虫的发生与防治

为害石榴的害虫种类较多 ,我国有 2 0 0多种 ,常见的有以下几种 :1　日本龟蜡蚧俗称蚧壳虫 ,属同翅目蜡蚧科 ,以若虫固着在叶片或新梢上吸食汁液 ,并分泌粘液 ,诱发煤污病 ,影响光合作用 ,使树势衰弱 ,引起大量落叶、落果 ,严重时可致绝产甚至全树枯死。1.1　防治方法1.1.1　药剂防治　若虫孵化后至蜡壳形成前是药剂防治的有利时机 ;生产上 ,可在若虫孵化期用 2 5 %亚胺硫磷 80 0～ 10 0 0倍液、5 0 %马拉硫磷 10 0 0～15 0 0倍液、5 0 %西维因可湿性粉剂 4 0 0～ 5 0 0倍液或5 0 %敌敌畏乳油 80 0～ 10 0 0倍液 ,每隔 7～ 10ｄ喷 1次 ,连喷…     

甜瓜枯萎病的发生与防治

甜瓜的枯萎病又称萎焉病,是一种典型的土传病害。本病在甜瓜的整个生育期均可发生,开花座果期和果实膨大期为发病高峰,对甜瓜的生产危害较大。笔者根据多年的经验,将甜瓜枯萎病的发生与防治分述如下。     

西瓜枯萎病的发生与防治

西瓜枯萎病（ＷａｔｅｒｍｅｌｏｎｆｕｓａｒｉｕｍＷｉｌｔ）又叫西瓜“死秧”。是蔚县西瓜生产的一大重要病害 ,一旦发病 ,轻者减产３０% ,重者减产５０% ,甚至绝收。近１０年来 ,由于西瓜种植面积不断扩大 ,而且轮作倒茬困难 ,致使西瓜枯萎病连年发生且愈来愈重 ,直接威胁着西瓜生产 ,严重影响其产量和质量。一、发生特点西瓜枯萎病是一种土传病害 ,一般在座果期开始发病。１．叶片症状。发病初期叶片从后向前逐渐萎蔫 ,似缺水状 ,中午最明显 ,但早晚可恢复 ,３～６天后 ,整株叶片枯萎下垂不能复原。２．茎部症状。茎蔓部缢缩 ,有的病部…     

胡椒枯萎病的发生情况及防治

胡椒枯萎病的发生情况及防治安贤书（华南热带作物科学研究院椰子研究所海南省文昌县５７１３２１）胡椒枯萎病由尖孢镰刀孢菌（Ｆｕｓａｒｉｕｍｏｘｙｓｐｏｒｕｍｆ．ｐｉｐｅｒｉｓ）引起可导致幼龄和封顶胡椒大量枯死。该病１９８８年在海南省文昌县和琼海市胡椒园里...     

百合枯萎病发生规律及防治研究

百合枯萎病是甘肃省百合产区近年来新发生的一种重要病害。研究证明,百合枯萎病系由尖孢镰刀菌(Fusarium oxysporum Schlecht.)、串珠镰刀菌(F.moniliform Sheldon)和茄病镰刀菌[F.solani(Mart.)Sacc.]侵染所致。病菌以菌丝体在种球内,或以菌丝体、厚垣袍子及菌核随病残体在土壤中越冬,成为翌年的主要初侵染源。病害的发生与连作、线虫、栽培技术及气候因素等密切相关。多菌灵对此病有显著防治效果。     

云南发现石榴枯萎病

 石榴枯萎病是云南省石榴生产中近年发生的一种毁灭性病害,并有逐渐加重的趋势,对云南石榴种植业威胁极大。     

百会枯萎病发生规律研究

百会枯萎病是江西省百合严重发生的一种病害．研究表明．病菌以菌丝在种球内,或以菌丝体、厚垣孢子及菌核随病残体在土壤中越冬,成为翌年的主要初侵染源．病害的发生与品种、连作、种球带菌、栽培技术及气候因素等密切相关．     

漳州市粉蕉枯萎病的发生及防治对策

粉蕉枯萎病是福建省补充的植物检疫对象。随着种植结构的调整 ,由于粉蕉因具有抗逆性强、品质佳、经济效益高等优点 ,为漳州市农业结构调整中主要发展的作物之一 ,并逐渐连片规模种植。与此同时 ,因忽视该病的检疫防治工作 ,造成了粉蕉枯萎病迅速扩散蔓延 ,普遍发生危害 ,已成为漳州市粉蕉生产中亟需解决的问题。为此 ,本文根据近年来的实践对该病害的发生危害、防治对策总结简述如下。1　症状与发生危害1 .1　症状系统观察表明 ,漳州市粉蕉枯萎病与香蕉枯萎病所表现症状的主要特征相似 ,即发病的焦株下部叶片叶缘首先黄化 ,并逐渐扩大至中…     

甘薯长喙壳菌产生芳香性气体物质研究进展

根据国内外相关文献报道及作者的研究实践,评述了甘薯长喙壳菌（Ceratocystis fimbriata Ell. et Halst.）及其产生芳香性气体物质的组成、影响因素、收集检测方法和应用价值;比较了芳香性气体物质几种收集方法的优劣和技术难点;分析了甘薯长喙壳菌产生芳香性气体物质特征在天然香味物质获取新途径、农作物废料再利用和作物病害防治方面的潜在应用前景;提出了围绕甘薯长喙壳菌的生物学特性开展系统研究,加速开展芳香性气体物质收集方法的筛选、组分分析及其生物学效应为主的应用基础和应用技术综合研究的建议     

石榴枯萎病菌的遗传多样性研究

 利用随机扩增多态性DNA(RAPD)和小卫星标记(DAMD)技术分析中国石榴枯萎病菌 (Ceratocystis fimbriata)的遗传多样性,并对来自印度、巴西、美国、新西兰、巴布新几内亚等多种寄主的C. fimbriata样品进行扩增,结果显示：所有C. fimbriata在遗传相似系数0.70 (RAPD)和0.60(DAMD)时均被分为4个相似的组群,其中中国石榴枯萎病菌间及其与芋头黑腐病菌(中国)具有一致的同源性(similarity index：1.00),而其它不同寄主来源的分离菌显示出一定的多态性。来自印度的石榴枯萎病菌与来自中国的有明显差异(RAPD,DAMD遗传相似系数分别为0.83和0.71),中国芋头寄主分离菌与巴西芋头分离菌间也存在一定差异。相对于来自印度石榴C. fimbriata来说,来自中国石榴与巴西芋头的分离菌有更近的系统发育关系。所有来自甘薯寄主的C. fimbriata 聚类为一个单独的分支。这表明供试的所有中国石榴菌株间及与中国芋头菌株间均具有一样的基因型,与印度同寄主(石榴)的C. fimbriata基因型存在明显差异。     

Genetic variation in populations of the cacao wilt pathogen, Ceratocystis cacaofunesta

Ceratocystis cacaofunesta (=  Ceratocystis fimbriata ) causes a lethal wilt disease of cacao ( Theobroma cacao ) in Latin America. Polymorphic microsatellite markers, (CAT)₅ nuclear DNA fingerprints and Hae III mitochondrial DNA fingerprints were used to compare genetic diversity among isolates of C. cacaofunesta collected from populations in western Ecuador, Costa Rica, Colombia, and Rondônia and Bahia in Brazil. Microsatellite markers and nuclear DNA fingerprints separated Ecuadorian isolates from isolates of the other four populations, and these two major groups correspond to genetic lineages already identified from ITS-rDNA sequences and intersterility groupings. Mitochondrial DNA fingerprints also demonstrated substantial diversity and split the Ecuadorian isolates into two groups. All marker types showed limited variation in the Colombian, Costa Rican and Bahian populations, as might be expected for introduced populations that have gone through recent genetic bottlenecks. In contrast, the Rondonian and western Ecuadorian populations showed gene diversity values similar to natural populations of other Ceratocystis species. The Rondonian population was the only sampled population in the native range of T. cacao (the Upper Amazon), and the putatively introduced populations were more closely related to the Rondonian population than to the western Ecuadorian population. The Ecuadorian population is in an area with other native Theobroma species, which may serve as natural hosts.     

9种生物制剂对甘薯长喙壳菌的抑制作用及防治效果

为筛选防治甘薯黑斑病的生物农药,测定了9种生物制剂对甘薯长喙壳菌孢子萌发和菌丝生长的抑制作用,并进行了防治效果验证。结果表明,四霉素对分生孢子萌发以及菌丝生长均表现出最强的抑制作用,EC50分别为0.10和0.15 mg/L;丁子香酚次之,EC50分别为0.24和0.93 mg/L。四霉素对薯苗黑斑病具有较好的防治效果,当接种甘薯长喙壳菌分生孢子浓度为5×104孢子/m L时,四霉素有效用量6与9 mg/L处理的防治效果分别为66.67%和78.57%;当接种浓度为5×105孢子/m L时,四霉素有效用量6与9 mg/L处理的防治效果分别为77.44%和90.23%。本研究为生物农药应用于甘薯黑斑病的防治提供了依据。     

Comparison of populations of the wilt pathogen Ceratocystis albifundus in South Africa and Uganda

Ceratocystis albifundus is an important fungal pathogen of Acacia mearnsii trees in South Africa. In a previous study, a high level of gene diversity was demonstrated in a South African population of C. albifundus . This, together with the occurrence of the pathogen on native Protea species and its exclusive occurrence in South Africa, led to the hypothesis that C. albifundus is probably native to that country. More recently, C. albifundus has been reported from A. mearnsii in south-western Uganda. The aim of this study was to compare the populations of C. albifundus from Uganda and South Africa based on genetic diversity, population structure and possible gene flow. This was achieved using codominant microsatellite markers developed for the closely related species Ceratocystis fimbriata . Available isolates for comparison were from six different areas of South Africa and six jungle stands in Uganda. Eight of the 11 available markers amplified loci in C. albifundus . Gene diversity was higher in the Ugandan population, but genotypic diversity was greater for the South African isolates. There were no common genotypes between the two populations and they shared only 22% of the total alleles. The populations were genetically isolated from each other and highly substructured within. There was no association between isolates collected from the same geographic locations, and gene flow between the two populations was low. Results suggest that C. albifundus was probably not introduced into Uganda from South Africa but rather that an ancestral population, yet to be discovered, is the source of both populations.     

Gummosis and wilt of Acacia mearnsii in South Africa caused by Ceratocystis fimbriata

A dieback of Acacia mearnsii trees was observed in the Mkomasi river valley, Natal Province, South Africa. A fungus, tentatively identified as Ceratocystis fimbriata , was consistently isolated from affected twigs and branches. Reinoculation of the pathogen resulted in the development of typical wilt and dieback of A. mearnsii seedlings and saplings and in a dieback of Protea cynaroides plants. This is the first report of this disease in South Africa.     

Resistance of kiwifruit cultivars to ceratocystis wilt: An approach considering the genetic diversity and variation in aggressiveness of the pathogen

Kiwifruit (Actinidia spp.) is native to southern China, but was first cultivated in New Zealand and then spread worldwide. Emerging diseases such as ceratocystis wilt have attracted the attention of kiwifruit growers due to the great losses observed in southern Brazil. Effective control can be achieved by screening for resistance, but the genetic variability of the pathogen must be considered. Thus, this study aimed to assess the genetic diversity and variation in aggressiveness of Ceratocystis isolates from kiwifruit in southern Brazil and then evaluate the resistance of kiwifruit cultivars with the most aggressive isolates. A collection of 46 isolates were obtained from southern Brazil and 14 simple-sequence repeat (SSR) markers was successfully used for genotyping. Out of 14 markers, 13 were polymorphic and identified 26 genotypes. Fourteen distinct genotypes were tested on a susceptible cultivar to select the most aggressive ones. Finally, inoculation with an equal mixture of five of the most aggressive isolates was used to evaluate the resistance of seven kiwifruit cultivars: Red Arguta, Green Arguta, Allison, Chieftain, Hayward, Monty, and Tomury. Cultivars varied in levels of susceptibility, with disease severity ranging from 40% to 100%. Considering the length of stem lesions, Chieftain showed the lowest level of severity at 40%, while no wilt symptoms were observed at 45 days after inoculation. In addition to the seven cultivars, a half-sibling progeny with 618 plants of the rootstock cv. Bruno was also assessed, but only seven individuals were resistant. These seven plants can be cloned and used as resistant rootstocks in commercial orchards.