黄岩橘区柑橘黄龙病发生流行原因及防控对策

2002年11月,黄岩橘区首次发现柑橘黄龙病疫情,当年全区只有院桥、沙埠2镇的36个行政村发生,病树8 510株。2003年有7个乡(镇、街道)共99个行政村发病,病树增加到113 115株。到2004年,整个黄岩橘区除富山乡、北城街道之外,其余17个乡(镇、街道)都已发生柑橘黄龙病,发病村数为225个,病树达312 105株。发病比较严重的9个乡(镇、街道),病株率为1!47%～44!61%,发病较轻的8个乡(镇、街道),病株率为0!0008%～0!85%。为此,笔者对近3年黄岩橘区柑橘黄龙病发生流行的原因进行研究与分析,提出了防控对策。1发生流行原因分析1)未经检疫,擅自调运柑橘类苗…     

恩施自治州马铃薯晚疫病发生原因及防控对策

马铃薯是恩施自治州重要粮食作物之一,马铃薯晚疫病是制约马铃薯增产丰收的最大障碍,本文从多层面分析了马铃薯晚疫病的发生原因,并提出相应防控对策。     

重庆山地烟区烟草病虫害绿色防控模式的探索

通过对重庆市奉节县烟区6年来开展的烟草病虫害绿色防控实践进行总结,提出了适应重庆山地烟区的绿色防控模式,形成了集保障机制建立、分区域实施、技术措施配套、工作实施保障等4个方面的经验,提出了未来烟区常态化、高质量推进绿色防控的工作方向.     

烟草根结线虫发生原因分析及治理对策

近年来 ,“两烟”双控 ,威宁烟草从２万ｈｍ２ 降为１万ｈｍ２。 ,由于传统的耕作方式未得到改进 ,使烟草根结线虫发生呈现上升趋势。１９９８至２０００年连续３年严重发生。据调查 ,地处半干旱河谷地带的轻砂质壤土发生面积达１５%以上 ,严重影响了烟叶的产量和质量。１发生原因１．１固有的基础条件为烟草根结线虫提供了良好的生存环境威宁地处云贵高原 ,贵州西部的乌蒙山区 ,属高原丘陵地貌 ,地面起伏平缓 ,相对高差５０ｍ～１００ｍ。由于受西南季风和小气候的控制 ,气候条件差别很大。在温和半干旱河谷地带、冬暖夏凉 ,小区气候突出 ,…     

宜都市玉米锈病大发生原因及防控对策

玉米是宜都市重要的粮食作物,是山区农民的主要经济来源之一.近年来我市玉米受到了玉米锈病的严重威胁.本文总结了宜都市玉米锈病的发生特点,分析大发生的原因,提出了具体的防控对策.     

田东县稻飞虱发生严重原因分析及防控对策

稻飞虱是田东县水稻常发性、普发性、重发性害虫,近10 a来主害代发生都在3级以上,给水稻生产造成严重威胁.根据田东县历年稻飞虱发生为害情况与气候、苗情、田间管理、防治措施等的关系,探讨提高稻飞虱防治效果的最佳方法和对策,最大限度地降低稻飞虱对水稻生产的危害.     

山西省地下害虫加重发生原因分析及防控对策

<正>地下害虫是我国农作物的重要害虫,种类多,分布广,食性杂。其主要为害作物地下部分或靠近土表部分的根、茎。作物受害后轻者萎蔫,生长迟缓,重的干枯死亡,造成缺苗断垄,导致减产。山西省地下害虫以蛴螬、金针虫、蝼蛄、地老虎等发生较为严重。通过20世纪末连续多年的防治,其为害基本得到控制,由主要害虫逐渐变为次要害虫,为害大大减轻。     

象州县桑树青枯病发生原因分析及防控对策

1桑树青枯病发生概况 种桑养蚕在象州县已有30多年的历史,现已成为该县的支柱产业之一,是当地农民发家致富的好门路。据统计,到2010年底止,全县已有桑园面积1.51万公顷,养蚕量达到75.2万张,产茧量61.36万担,种桑养蚕总产值达8.9亿元。桑树青枯病是桑树毁灭性病害,2010年发生面积约0.2万公顷,尽管目前属零星发生,但各桑树种植区基本都有发生,且呈逐年加重之势。     

通城县稻飞虱发生为害原因分析及防控对策

通城县位于湘、鄂、赣三省交界之处,湖北的最南端,属于丘陵地区,间杂着高山半高山,年平均气温17℃左右,年平均降雨量1 500mm左右,全年无霜期260d左右.全县早、中、晚水稻种植面积常年2.67万hm2以上,稻飞虱是发生为害最为严重的迁飞性害虫之一,20世纪80年代中期以前以褐飞虱为主,主要在中、晚稻上间隙暴发为害,自1987年开始,白背飞虱种群数量不断上升,已与褐飞虱同为本地区优势种群,暴发频率显著增多,为害世代增加,已扩展到早、中、晚稻都有为害,对全县水稻生产构成重要影响,必须加强监测控制,减轻其为害损失.     

崇左蔗区甘蔗螟虫发生动态及防控对策

甘蔗螟虫是甘蔗的主要害虫之一,且分布广,危害大,会造成甘蔗产量减少和糖分损失,影响蔗糖产业健康发展.通过对崇左蔗区甘蔗螟虫的种类、发生动态和为害特征的介绍,从气候条件、品种选择、栽培制度、防控技术及基层植保服务等方面分析了甘蔗螟虫逐年加重危害的原因,并提出了防控对策.     

烟草叶片接种野火病菌后蛋白质表达差异

为了解烟草受野火病菌侵染后蛋白质表达变化情况,探讨烟草品种的抗病机制,本研究对烟草抗病品种‘K346’叶片进行人工接种,在接种后0～72h内分9次在接种点周围取无病原菌叶片组织提取叶片总蛋白,利用双向电泳技术分析接种处理叶片与未处理叶片的蛋白质表达差异,并选取6个减量表达蛋白点和4个增量表达蛋白点进行MALDI-TOF-MS质谱分析及数据库搜索鉴定,结果表明,6个减量表达蛋白包括参与植物呼吸代谢途径的ATP合成酶CF1α亚基、ATP合成酶CF1α链以及参与植物能量代谢循环途径的1,5-二磷酸核酮糖羧化酶/加氧酶相关蛋白;4个增量表达蛋白包括参与植物氨基酸代谢途径的谷氨酰胺合成酶、参与糖类和碳循环相关途径的高等植物光系统II氧复合物中Psbp A链蛋白、叶绿体景天庚酮糖-1,7-二磷酸酯酶和光捕获叶绿素a/b结合蛋白。经过蛋白质功能分析,推测烟草是通过加速植株生长、促进抗病相关糖和蛋白的表达、增强氨基酸代谢以及植株自身蛋白的修复等方式来提高抗病性。     

2007年临猗县苹果疱斑病大发生原因分析及采取的防治措施

近年来,苹果疱斑病在临猗县不同程度地发生,已严重影响本县农业生产、果农收入.县植保植检站2001～2007年连续7年对该病进行观察,分析了该病的发生原因,提出了防治措施.     

上海地区大豆细菌性疫病发生危害与防治

大豆细菌性疫病又称大豆细菌性斑点病[Pseu-domonas syringaepv.glycinea(Coerper)Young,Dye&Wilkie],是我国和世界大豆产区主要病害,导致大豆产量损失和品质下降。据报道,在适宜发病条件下此病可使大豆减产18%~22%,一般减产20%左右,最高达50%以上。近年来,随着上海地区菜用大豆种植面积的不断扩大,发生了大豆细菌性疫病。为防治该病进行了田间流行调查和发生特点观测。1病害发生情况2002~2004年,对上海郊区的大豆种植地进行了调查,根据大豆细菌性疫病危害程度进行病级标准划分。0级:无症;1级:复叶上有1~5个病斑;2级:复叶上有6~10个病斑;3…     

春雷霉素和噻霉酮对番茄斑疹病菌联合毒力及防病效果

通过平板菌落计数法测定了春雷霉素和噻霉酮对引起番茄斑疹病的丁香假单胞杆菌番茄致病变种(Pseudomonas syringae pv.tomato)的毒力及两种药剂混配的联合毒力。结果表明:春雷霉素和噻霉酮对番茄斑疹病菌具有抑制作用,EC50值分别为5.32μg/mL和2.66μg/mL;联合毒力的测定结果表明:春雷霉素和噻霉酮质量比1∶1的配比增效作用最强。田间试验结果表明:春雷霉素、噻霉酮及春雷霉素与噻霉酮(1∶1)混剂,田间防治效果均达到80%以上,混剂防治效果显著高于单剂。     

Pseudomonas syringae pv. syringae on pepper seedlings in Italy

Pseudomonas syringae pv. syringae causing leaf spot on pepper seedlings grown in a plant bed is reported in Italy for the first time. The pathogen was identified by means of biochemical, physiological and pathogenicity tests as well as by SDS-polyacrylamide gel electrophoresis of whole-cell proteins. The bacterial isolates showed positive for ice nucleation and biocide production.     

Comparison of ethylene-producing Pseudomonas syringae strains isolated from kudzu (Pueraria lobata) with Pseudomonas syringae pv. phaseolicola and Pseudomonas syringae pv. glycinea

The relationships among strains of Pseudomonas syringae pv. glycinea (Psg) and Pseudomonas syringae pv. phaseolicola (Psp) isolated from kudzu ( Pueraria lobata) and bean ( Phaseolus vulgaris) were investigated. All strains tested showed a close phenotypic similarity, with the exception of the utilization of inositol and mannitol as well as the production of toxins. On this basis the strains could be divided into three groups. Group 1 consists of all strains of pathovar glycinea, group 2 includes all Psp strains isolated from kudzu, and all Psp strains isolated from bean belong to group 3. This grouping was also reflected in the genetic fingerprints using the polymerase chain reaction (PCR) with primers that anneal to dispersed repetitive bacterial sequences (rep-PCR). The rep-PCR generated fingerprints were unique for each of the three groups. The strains of group 2, Psp strains isolated from kudzu, possess certain characteristics of group 1 (ethylene production) and group 2 (phaseolotoxin production). The Psp strains from kudzu can be clearly differentiated from Psp strains isolated from bean. They utilize mannitol, produce ethylene, and are strongly pathogenic to kudzu, bean, and soybean. The results obtained show that the Psp strains from kudzu should be separated from the pathovar phaseolicola and should represent their own pathovar.     

Specificity of polyclonal antibodies to different antigenic preparations of Pseudomonas syringae pv. pisi strain UQM551 and Pseudomonas syringae pv. syringae strain L

Polyclonal antibodies were produced against sonicated and heat-killed cells of Pseudomonas syringae pv. pisi strain UQM551 and Pseudomonas syringae pv. syringae strain L, and their specificities were compared. Evidence is presented that the serological specificity between these two pathovars lies in surface antigens. Of the surface antigens purified and tested, only flagella and lipopolysaccharide from the cell wall showed no cross-reactivity with heterologous antisera. Antisera to glutaraldehyde-fixed flagella of the two strains showed a high level of specificity. At a species or genus level, antisera prepared from heat-killed cells of P. syringae distinguished this species from all other bacterial species and genera tested, including strains of Pseudomonas fluorescens, Escherichia coli, Agrobacterium and Rhizobium.     

Similarity between Copper Resistance Genes from Pseudomonas syringae pv. actinidiae and P. syringae pv. tomato

Twenty-eight strains of Pseudomonas syringae pv. actinidiae isolated in 1984, 1987 and 1988 from kiwifruit orchards in Japan were tested for their resistance to copper sulfate. All strains isolated in 1984 were copper sensitive with a minimum inhibitory concentration (MIC) of cupric sulfate of 0.75 mM. However, some strains isolated in 1987 and 1988 were resistant, with the MIC ranging from 2.25 to 3.0 mM. All copper-resistant strains contained at least one of two plasmids, pPaCul (about 70.5 kb) or pPaCu2 (about 280 kb), or both. In a copper-resistant strain Pa429, the location of the copper-resistance gene(s) was examined by insertional inactivation with Tn5. The MIC of copper sulfate in the copper-sensitive mutant obtained by Tn5 tagging decreased from 2.75 to 0.75 mM. The 14.5 kb BamHI fragment, designated pPaCuB14, containing the same locus mutagenized with Tn5 was cloned from pPaCu1. However, pPaCuB14 did not confer copper resistance in the transformant of copper-sensitive strain Pa21R, suggesting that this clone did not contain a full set of copper-resistance gene(s). Then a cosmid library of pPaCu1 was constructed and six cosmid clones hybridized with pPaCuB14 were selected. One of the six cosmids, designated pPaCuC1, conferred a near wild-type level of copper resistance in the transformant of the copper-sensitive strain. pPaCuC1 had a homologous region that hybridized with all of the PCR-amplifled fragments of copA, copB, copR, and copS genes of P. syringae pv. tomato. DNA sequence analysis of the homologous region revealed the existence of four open reading frames (ORF A, B, R and S) oriented in the same direction. The predicted amino acid sequences of ORF A, B, R and S had 80, 70, 97 and 95% identity with CopA, B, R and S of P. syringae pv. tomato, respectively. Received 5 July 2001/ Accepted in revised form 27 September 2001     

Bacterial inflorescence rot of grapevine caused by Pseudomonas syringae pv. syringae

Molecular sequencing (rpoB) and standard pathological and microbiological methods identified Pseudomonas syringae pv. syringae (Pss) as the causal agent of bacterial inflorescence rot of grapevines (Vitis vinifera) in three vineyards in Tumbarumba, NSW, Australia in 2006 and 2007. Pss strains from shrivelled berries and necrotic inflorescences of diseased grapevines were used to inoculate leaves and inflorescences of potted cv. Semillon grapevines. Pss caused disease symptoms similar to those experienced in the field, including angular leaf lesions, longitudinal lesions in shoot tissues and rotting of inflorescences from before flowering until shortly after fruit set. High humidity promoted symptom severity. The necrotic bunch stem and leaf lesions were susceptible to the development of Botrytis cinerea infections. Cryo‐scanning electron microscopy (cryoSEM) indicated that Pss entered leaves and inflorescence tissues via distorted, open, raised stomata surrounded by folds of tissue that appeared as ‘star‐shaped’ callose‐rich complexes when viewed by UV light microscopy. In necrotic tissues, cryoSEM revealed Pss within petiole parenchyma cells and air‐filled rachis xylem vessels. This is the first report of inflorescence and hence fruit loss caused by Pss in grapevines. The disease is described as ‘bacterial inflorescence rot’ and regarded as one that expands the previously reported pathology of grapevines caused by P. syringae. This study also indicated that infection by Pss might promote destructive B. cinerea infections when the fungus is already present but latent, although further experimentation is needed to prove such an interaction.     

Induction of pear blossom blast caused by Pseudomonas syringae pv. syringae

Conditions were established for inducing pear blossom blast caused by Pseudomonas syringae pv. syringae on both attached and detached shoots. The incidence of blossom blast was proportional to the logarithm of the P.s. pv. syringae population under optimal temperature, moisture, and bloom developmental stage. Highest incidence of blossom infection followed occurrence of a major exotherm (an increase in temperature caused by the heat of fusion from ice formation within blossom tissue) in the presence of P. s. pv. syringae. The exotherm was detected inside ovary tissue at temperatures ranging from –1.8 to –3.5 C. Wetness duration following the thawing process was less important than wetness during and immediately after the freeze event. Blossoms inoculated, then air-dried or removed from low-temperature treatment prior to occurrence of an exotherm, had a low incidence of infection, The full bloom stage of blossom development was more susceptible to blossom blast than either the open cluster or tight cluster stages of development.