怀集县柑橘炭疽病发生与无公害防治技术

分析怀集县柑橘炭疽病的发生现状和发生普遍的原因,提出无公害防治技术,为怀集县柑橘产业的发展保驾护航,促进柑橘产业的发展。     

柑橘溃疡病检疫与防治

细菌性溃疡病是严重危害世界柑橘产业的重大检疫性病害之一,柑橘溃疡病引起落叶、枯枝和落果,溃疡病斑导致果品质量降低,影响外贸出口。世界各国长期以来对病害采取严格苗木检疫、疫区病树铲除、零星病害药剂防控的综合治理措施;新近美国农业部推出"柑橘健康种植行动计划";2007年7月中国农业部正式启动"柑橘非疫区建设和维护"项目,总体目标在于防控柑橘溃疡病的发生和传播,确保柑橘产业的安全。     

10%草甘膦水剂杀灭柑橘溃疡病病树效果试验

应用10%草甘膦水剂杀灭柑橘植株,为铲除柑橘溃疡病疫情作了初步的探索性试验。结果表明:10%草甘膦水剂处理树蔸杀灭效果明显;叶面及树干喷雾杀灭效果较差。建议在铲除柑橘溃疡病疫情时先将柑橘树地上部分砍掉销毁,再用10%草甘膦水剂15倍液杀灭其树蔸,能彻底消除柑橘溃疡病活体寄主。     

柑橘溃疡病的根除历史及广西主栽柑橘品种的抗病性

柑橘溃疡病是影响世界柑橘生产的重大检疫性病害。美国、澳大利亚和中国等国家采用在疫区大面积砍伐柑橘树的方法试图根除柑橘溃疡病,但经过一个世纪的努力,柑橘溃疡病并未被完全根除。广西地处热带和亚热带地区,气候温暖,雨水丰沛,利于柑橘溃疡病菌的繁殖与传播,使广西主栽的柑橘品种(沃柑、茂谷柑、脐橙、沙田柚等)均表现为高感溃疡病特性。生产上应以推广抗病品种为重点,配合使用无菌苗木和推行健康栽培管理措施,优先使用拮抗活菌剂的综合技术,以达到有效防控柑橘溃疡病的目的。     

30%王铜悬浮剂防治柑橘溃疡病试验

在道县下汶脐橙基地,用30%王铜悬浮剂等药剂对柑橘溃疡病进行田间药效试验示范。结果表明,30%王铜悬浮剂600倍液对柑橘溃疡病的防治效果较理想,其保果和保叶效果均达80%以上,整个试验期间无药害发生,该药剂值得在生产上推广应用。     

加强对柑橘溃疡病实施检疫的几点意见

柑橘是我国南方生产的重要水果,在生产发展中,加强对柑橘溃疡病的检疫,以保护无病县(市)和疫区内无病小区的柑橘生产免受柑橘溃疡病危害是十分重要的.现就柑橘溃疡病检疫中的几个问题提出下述意见,供参考.     

3种杀菌剂对柑橘溃疡病的防治效果

溃疡病是柑橘的主要病害之一,也是广西南宁区域沃柑的主要病害,严重影响沃柑品质。本试验选用47%春雷·王铜WP、20%噻唑锌SC、20%噻菌铜SC等3种杀菌剂,对2 a生沃柑溃疡病进行了防效对比试验,结果表明,47%春雷·王铜WP 500倍液对柑橘溃疡病的防治效果较好,防治效果达到84.25%,并且对柑橘安全、无负面影响。     

监利县柑橘溃疡病疫情发生与控制

柑橘溃疡病属国内植物检疫对象,在我国南方柑橘产区零星发生。2011年5月中旬,监利县植物检疫站在全县进行柑橘溃疡病的疫情普查时,首次在红城乡、容城镇发现疫情。近年来,由于市场的需求,监利县果树面积逐年扩大,2011年柑橘种植面积333.5hm2,柑橘溃疡病的传入,严重危及到全县柑橘安全生产。两年来,监利县     

柑橘溃疡病发生特点及综合防控技术

柑橘溃疡病是柑橘重要病害之一,为国内外植物检疫对象.在我国柑橘产区都有发生,南方各省尤为严重.该病菌主要侵染芸香科植物,以甜橙、脐橙、酸橙等品种最为感病.据资料记载,黄岩于1955年发现柑橘溃疡病,当时属零星发生,发生面积很少.随着甜橙类、柚类、杂柑类等-些易感病品种的逐渐引进、推广,成年结果树的发生面积有所扩大.     

松脂酸铜防治柑橘溃疡病效果研究

2009-2010连续2年田间药效试验结果表明,试验药剂松脂酸铜20%可湿性粉剂对柑橘叶片和果实溃疡病具有较好防效,400mg/kg处理的防效分别可达75.35%和70.69%,是防治柑橘溃疡病较为理想的药剂。     

靓果安防治脐橙溃疡病田间药效试验

在赣州市经济开发区脐橙园进行了靓果安防治溃疡病的药效试验。试验结果表明,2.6%靓果安AS单剂使用100～800倍液对赣南脐橙溃疡病防治有一定的效果,其防效分别为：300倍液处理防效为78.30%,500倍液处理防效为70.37%,800倍液处理防效为63.29%。所有处理对脐橙枝梢、叶片及幼果安全,对有益昆虫、微生物未发现副作用,对环境也未发现严重污染。因此,建议在赣南脐橙产区加大推广与应用靓果安AS单剂以有效防治溃疡病的危害。     

赣南脐橙溃疡病及其研究现状

对赣南脐橙的重要病害之一——溃疡病的症状、危害、病原、发生规律及防治方法进行了综述。其中重点介绍了防治研究的最新进展并对此提出了建议。     

柑橘花期蓟马的种类与鉴定

为明确柑橘花期蓟马种类,以柑橘园为实验基地,系统调查橘园中蓟马的种类。经形态学鉴定共发现3种蓟马,且3种蓟马的形态分别与棕榈蓟马（Thrips palmi Karny）、淡色蓟马（Thrips flavus Schrank）和华简管蓟马（Haplothris chinesis Pfiesner）极其相似。对3种蓟马分别进行单头虫体的基因组DNA提取,对其ITS2基因序列进行PCR扩增并测序,测序结果登入NCBI数据进行比对,结果表明3种蓟马分别与棕榈蓟马（Thrips palmi Kamy）、淡色蓟马（Thrips flavus Schrank）和华简管蓟马（Haplothris chinesis Priesner）的相似度均达99％。     

6个日本脐橙优良品种对柑桔溃疡病的抗性调查

在广西象州柑桔溃疡病疫区引种试栽了6个日本脐橙品种，丹下，铃木，森田，清家，白柳，吉田。经３年调查观察，发现品种间抗病性和丰产性有不同程度的差异，其中以丹下表现最好，可在疫区适当发展这一优质脐橙品种。     

AR模型在柑桔溃疡病测报中的应用

 柑桔溃疡病发生程度的预测是进行该病治理的重要依据。本研究用自回归方法对2004年3月12日~2005年4月13日期间调查的病情原始数据进行标准化、平稳化处理以及模型的参数估计和拟合检验,所得AR (14)模型可以精确预测溃疡病发生趋势。     

Transient expression of pepper Bs2 gene in Citrus limon as an approach to evaluate its utility for management of citrus canker disease

The pepper Bs2 gene confers resistance to Xanthomonas campestris pv. vesicatoria (Xcv) pathogenic strains containing the avrBs2 avirulence gene in susceptible pepper and tomato. The avrBs2 gene is highly conserved in the Xanthomonas genus and when bacteria lack this gene their growth in a susceptible host is diminished, indicating that the avrBs2 gene product could confer an adaptive advantage to the pathogen. The avrBs2 of Xanthomonas citri subsp. citri (Xcc), cause of citrus canker, shares 96% homology with avrBs2 of Xcv. To evaluate if Bs2 could recognize avrBs2 of Xcc in citrus plants and thereby activate plant defence mechanisms to increase resistance to canker, transient expression experiments were conducted using Agrobacterium tumefaciens in lemon plants subsequently challenged with wildtype Xcc. The results showed that transient expression of Bs2 reduced canker formation in lemon and induced plant defence mechanisms, as shown by callose deposition and PR‐1 expression. Moreover, when an avrBs2 mutant of Xcc was used, no decrease in disease symptoms was observed. This work shows that the Bs2 gene from Solanaceae is functional in lemon, a member of the Rutaceae family. Therefore, Bs2 is a potential candidate gene for stable expression in transgenic citrus plants in order to improve resistance to canker disease.     

The Effect of Irrigation Practices on the Spatio-temporal Increase of Asiatic Citrus Canker in Simulated Nursery Plots in Reunion Island

Asiatic citrus canker is a potentially severe disease of several citrus species and cultivars in many tropical and subtropical areas. In such areas, infected nursery plants constitute an important source of primary inoculum for newly established citrus groves. The influence of overhead, drip, and mist irrigation systems on the development of Asiatic citrus canker was studied in simulated, Mexican-lime nurseries in Reunion Island. Overhead irrigation exacerbated the increase of disease incidence and severity caused by a streptomycin-resistant strain of Xanthomonas axonopodis pv. citri. The temporal development of Asiatic citrus canker for overhead irrigated nursery plots was best described by an exponential model, because disease incidence in these plots did not come close to an asymptote during the experimental period. This can be explained by the continuous production of new growth, susceptible to infection by Xanthomonas axonopodis pv. citri, and splash dispersal of Xanthomonas axonopodis pv. citri associated with overhead irrigation. Based on spatial correlation and spatio-temporal analyses, aggregated disease patterns were found irrespective of the irrigation system. In overhead-irrigated plots, the spread of Xanthomonas axonopodis pv. citri lacked directionnality. Rainstorms of short duration and high intensity were apparently associated with disease increase in drip-irrigated plots. There is a need to improve cultivation practices in Reunion Island citrus nurseries to minimize Asiatic citrus canker incidence in nurseries and to minimize the introduction of Xanthomonas axonopodis pv. citri to new groves.     

Bacteria from the citrus phylloplane can disrupt cell–cell signalling in Xanthomonas citri and reduce citrus canker disease severity

Xanthomonas citri subsp. citri (Xcc) is the causal agent of citrus canker, a disease that affects almost all types of citrus crops. Production of particular Xcc pathogenicity factors is controlled by a gene cluster rpf, which encodes elements of a cell–cell communication system called quorum sensing (QS), mediated by molecules of the diffusible signal factor (DSF) family. Interference with cell–cell signalling, also termed quorum quenching, either by signal degradation or over‐production, has been suggested as a strategy to control bacterial disease. In this study, three bacterial strains were isolated from citrus leaves that displayed the ability to disrupt QS signalling in Xcc. Pathogenicity assays in sweet orange (Citrus sinensis) showed that bacteria of the genera Pseudomonas and Bacillus also have a strong ability to reduce the severity of citrus canker disease. These effects were associated with alteration in bacterial attachment and biofilm formation, factors that are known to contribute to Xcc virulence. These quorum‐quenching bacteria may represent a highly valuable tool in the process of biological control and offer an alternative to the traditional copper treatment currently used to treat citrus canker disease.     

运用自组织人工神经网络模型判别柑桔溃疡病始见期

 1984-1990年运用T.Kohonen自组织人工神经网络模型系统观察甜橙新梢萌芽(始花)的时期及有关天气资料,建立了柑桔溃疡病始见期预测的计算机智能专家系统。经1991年春梢及幼果的柑桔溃疡病斑始见期验证,预测准确,历史回验,符合率达100%。