玉米三种叶斑病混发时的流行过程及产量损失研究

 通过2年的田间小区人工接种试验,观察比较了玉米大斑病、弯孢叶斑病和灰斑病单独及混合发生时的流行过程及对玉米产量损失的影响。结果表明,在病害混发初期,病害间无明显的负相关性,随着病情的发展,病害间的负相关性逐渐增大并达到显著水平,说明病害间有明显的抑制作用。病害混发时造成产量损失并不完全等于各病害单独造成损失之和,其中大斑病和弯孢叶斑病、弯孢叶斑病和灰斑病混合发生所造成的损失约为各病害单独造成损失之和的76%～88%,大斑病和灰斑病混合发生所造成的损失可近似看作两种病害各自引起产量损失之和,3种病害同时发生时最终损失率约为各自造成损失之和的67%～72%。     

辽宁花生主栽品种(系)对褐斑病和网斑病抗性鉴定

本研究旨在明确辽宁花生主栽品种(系)对花生褐斑病和网斑病的抗性,以期为抗病育种及田间病害防治提供理论依据。试验采用田间自然病圃法,对辽宁主栽的16个花生品种(系)进行了褐斑病和网斑病田间抗性鉴定。结果表明,供试花生品种(系)对两种叶部病害抗性存在显著差异,但缺乏免疫和高抗品种。对花生褐斑病抗性鉴定结果表明,‘阜花17’属抗病类型,‘鲁花11’、‘铁引花2号’、‘良青8号’、‘新花2号’和‘锦花15’属中抗类型,其余属高感或感病类型。对花生网斑病抗性鉴定结果显示:‘鲁花11’、‘铁引花2号’和‘白花生’属抗病类型,‘黑花生’、‘新花2号’、‘花育20’、‘锦花14’、‘新花1号’、‘锦花15’和‘良青8号’属中抗类型,其余属高感或感病类型。多数花生品种(系)对花生叶斑病综合抗性较差。     

花生网斑病的防治

花生网斑病(Phoma arachidicola)发病快,蔓延迅速,引起中后期大量的落叶,直接影响花生的产量和品质.是急待防治的花生主要叶部病害.自1992年以来,通过对该病的系统调查,摸索出一套实用的防治技术.     

中国花生网斑病研究

花生网斑病是我国花生上新发生的一种叶部病害，近年来蔓延迅速，为害严重，经１９８３－１９９２年历时１０年的系统研究，摸清了该病症状、发生和为害规律、分布特点；明确该病的发生与主要发病因子的关联性；于国内首次明确了该病原菌的分类地位；摸清了病害发生程度与花生荚果产量损失率之间的函数关系，找出了受害较敏感的花生物候期，建立了防治经济阈值模型；筛选出目前最好的杀菌剂、生物制剂和物理保护剂以及较抗病的花生品     

花生网斑病不同病斑类型及其病原菌致病力差异

本文描述了河南省发生日趋严重的花生网斑病在田间出现的一种新的病斑类型,并结合已报道的两种病斑类型,对3种病斑类型的病原菌开展致病力差异研究。研究结果表明:田间新发现的花生网斑病病斑特征明显,综合分析后将花生网斑病病斑类型分别定为网纹型、类褐斑型和污斑型;同一花生品种上3种病斑类型病原菌菌株间存在明显的致病力差异,同一病斑类型菌株对不同花生品种的致病力也表现出显著差异。     

花生网斑病防治经济阈值模型研究

近几年研究了花生网斑病不同生育期发病对花生荚果产量的影响,以及不同发病程度与花生产量损失率的关系。建立了该病防治经济阈值模型x=10000C+2.089PVE/0.754PVE,为经济有效地防治花生网斑病提供了科学依据。     

花生网斑病的发生与防治

花生网斑病又叫褐斑病 ,纹斑病 ,是近年来发生趋重的一种新病害 ,2 0 0 0年滑县发生严重 ,造成花生中后期大量落叶 ,减产达 2 0 %～ 40 % .症状 :网斑病一般从花针期始始发 ,发病盛期在结荚期至成熟期 ,主要为害叶片 ,也为害叶柄和茎 ,植株下部叶片先受害 ,沿主脉主生圆形或不规则形黑褐色小点 ,周围有明显的褪绿圈 ,后形成边缘呈网纹状 ,不规则形褐色病斑 ,一般不透过叶面 ;若遇多雨天气 ,病斑较大 ;叶片一旦染病 ,极易脱落 ,叶槽茎受害 ,起初为小褐点 ,年扩展为边缘水渍状 ,中央凹陷、长条形成椭圆形病斑。病原及发病条件 ;该病病原为花生…     

不同时期使用农抗120控制花生网斑病侵染源的试验研究

用农抗１２０防治花生网斑病，不同使用方法效果不一。用常规喷洒叶面方法控制再侵染源，防效为２１．４％，相当于多菌灵（２９．４％）；用农抗１２０和杀菌剂（抗枯灵或多菌灵等）混合，在花生播种时喷洒地面一次，控制初侵染源，防效为４８．６％；用农抗１２０同杀菌剂混合，播种时喷洒地面，以控制初侵染源，７月上旬再喷洒叶面，控制再侵染源，效果最佳，防效高达７０％以下。     

早稻纹枯病不同病斑高率与产量损失的关系

本文研究了早稻纹枯病不同病斑高率与千粒重下降率、每穗损失率、空秕率的关系，初步明确了当病斑高率上升到0.6－0.7时，对产量有明显的影响，为纹枯病的测报提供了理论依据。     

不同时期使用农抗120控制花生网斑病侵染源的试验研究

用农抗120防治花生网斑病,不同使用方法效果不一。用常规喷洒叶面方法控制再侵染源,防效为21.4％,相当于多菌灵(29.4％);用农抗120和杀菌剂(抗枯灵或多菌灵等)混合,在花生播种时喷洒地面一次,控制初侵染源,防效为48.6％,用农抗120同杀菌剂混合,播种时喷洒地面,以控制初侵染源,7月上旬再喷洒叶面,控制再侵染源,效果最佳,防效高达70％以上。     

薏苡叶枯病和叶斑病调查与病原鉴定

对福建省龙岩市新罗区薏苡叶部病害进行了调查。用组织分离法,PSA平板培养经纯化后作病原鉴定,在其上发现了两种病害:薏苡叶斑病为一种新病害,病原鉴定为薏苡尾孢(Cercospora sp.);薏苡叶枯病为福建省首次记录,其病原为薏苡平脐蠕孢(Bipolaris coicis)。     

Effect of the new pyrazole carboxamide fungicide penthiopyrad on late leaf spot and stem rot of peanut

BACKGROUND: Management of early leaf spot (Cercospora arachidicola Hori.), late leaf spot [Cercosporidium personatum (Berk. & MA Curtis) Deighton] and stem rot (Sclerotium rolfsii Sacc.) of peanut (Arachis hypogaea L.) in the southeastern USA is heavily dependent upon sterol biosynthesis inhibitor (SBI) and quinone outside inhibitor (QoI) fungicides. Effective new fungicides with different modes of action could improve overall disease control and extend the utility of the current fungicides. Penthiopryad is a pyrazole carboxamide fungicide being evaluated for use on peanut. Field experiments were conducted from 2004 to 2007 to determine the effect of a range of rates (0–0.36 kg AI ha^?1) of penthiopyrad on leaf spot and stem rot and the relative efficacy of penthiopyrad and current fungicide standards chlorothalonil, tebuconazole and azoxystrobin. RESULTS: Leaf spot control in plots treated with penthiopyrad at 0.20 kg AI ha^?1 or higher was similar to or better than that for the chlorothalonil standard. The incidence of stem rot for all penthiopyrad treatments was usually less than that for the tebuconazole or azoxystrobin standard treatments. Pod yields for all penthiopyrad treatments were similar to or higher than those for the respective standards. CONCLUSION: Penthiopyrad has excellent potential for management of late leaf spot and stem rot of peanut, and may complement current SBI and QoI fungicides. Copyright © 2008 Society of Chemical Industry     

Tolerance of septoria leaf blotch in winter wheat

For individual varieties, tolerance of septoria leaf blotch was quantified by the slope of the relationship between disease and yield. Variation in disease severity and the associated yield responses were provided across two sites and three seasons of field experiments. Slopes were fitted by residual maximum likelihood for two contrasting models: (i) a fixed-effects model, where no prior assumptions were made about the form of the variety slopes; and (ii) a random-effects model, where deviations in individual variety slopes away from the mean variety slope formed a normal random population with unknown variance. The analyses gave broadly similar results, but with some significant differences. The random model was considered more reliable for predicting variety performance. The effects of disease were quantified as symptom area and green canopy duration. Models of the relationship between symptom area and yield were site-specific. When site effects were not taken into account, these models had poor predictive precision. Models based on the canopy green area gave robust predictions of yield and were not site-specific. Differences in disease tolerance were detected in a comparison of 25 commercial winter wheat varieties. Tolerance was not detected directly through symptom measurements, but instead through measurements of canopy green area, which provides a measurement of the effects of disease that accounts for differences in canopy size across sites and seasons. The varieties showing greatest tolerance tended to have lower attainable yield than the intolerant varieties. Presence of the 1BL/1RS chromosome translocation, which has been reported to increase radiation use efficiency, appeared to be associated with intolerance.     

Effect of varietal resistance on the yield loss function of wheat to nodorum blotch

Cultivar disease resistance ratings to nodorum blotch (caused by Parastagonospora nodorum) provide critical information to growers to assist with disease management. However, less has been done in terms of yield losses from diseases under different cultivar resistance scenarios. The purpose of this study was to characterize yield and quality loss responses to wheat nodorum blotch as influenced by variety partial resistance, epidemic intensity, and environment. The trial series includes four site/years in Western Australia. Five varieties, Magenta, Calingiri, Trojan, Janz, and Scout were used for all four trials. These varieties represented resistant/susceptible categories MRMS, MS, MSS, S, and SVS, respectively, and were selected on the basis that they were adapted to the western region, had similar maturities, and were resistant to diseases that were potential contaminants. Trials were sown in a strip-plot design with three replicates and five disease levels, with intersecting main-plots of varieties and disease levels, which facilitated comparisons across disease levels within varieties. Current categories of resistance were well reflected in yield and quality responses. A negative exponential relationship was observed between yield and disease, with a nonlinear yield loss function for both flag leaf and glume infection. This indicates that yield is most affected during early stages of disease on flag leaves and glumes. The functional form of yield loss response over four site years was similar among varieties, but varieties differed in their extent of disease expression. Partial resistance in commercial wheat varieties reduced yield loss by 40%–60% of losses observed in susceptible varieties.     

我国玉米灰斑病菌的种类及其分布调查

为了监测我国玉米灰斑病菌的种群及其分布,本研究于2016年－2019年从全国17省（直辖市）87地市（自治州）采集了1 341份玉米灰斑病样本,分离病原菌进行形态学和分子生物学鉴定。共分离到菌株4 186株,从中鉴定出玉蜀黍尾孢Cercospora zeae-maydis 3 272株、玉米尾孢C. zeina 914株。结果表明,引起我国玉米灰斑病的病原菌有玉蜀黍尾孢C. zeae-maydis和玉米尾孢C. zeina两个种,而且这两个种在我国的分布有一定的地域性。黑龙江、吉林、辽宁、内蒙古、河北、北京、天津、山东、山西和安徽地区的玉米灰斑病菌均为玉蜀黍尾孢;河南的西、南部和陕西的中、南部是玉蜀黍尾孢和玉米尾孢混合发生;湖北、四川和湖南虽然分离到了玉蜀黍尾孢和玉米尾孢两种菌,但以玉米尾孢为主;贵州和云南的玉米灰斑病菌均为玉米尾孢。     

西瓜叶斑病病原菌的鉴定及室内药剂筛选

2022年在上海市浦东新区西瓜上发生一种深褐色、不规则至近圆形斑的叶部病害。采用组织分离法对病害样本进行分离, 分离物SHCCC01经柯赫氏法则验证具有较强致病性。根据分离物的菌落特征、分生孢子形态、生物学特征以及基于核糖体内部转录间隔区(internal transcribed spacer, ITS)、组蛋白基因(histone, His)、真核翻译延伸因子1α(translation elongation factor 1α, TEF-1α)和肌动蛋白 (actin, Act)基因联合系统发育分析等, 将病原菌鉴定为瓜类尾孢Cercospora citrullina。10种杀菌剂对该病原菌的毒力测定试验结果表明:氟啶胺、己唑醇、氟环唑、戊唑醇等4种药剂对病原菌的抑菌活性较高, 其EC50分别为0.375 2、0.575 4、1.472 3、1.890 2 μg/mL。这些结果为西瓜尾孢叶斑病的防控和杀菌剂登记提供了重要依据。     

The effect of timing of fungicide applications on control of frogeye leaf spot and grain yield of soybeans

Soybean cultivar Samsoy 1, and the breeding lines TGx 849-313D and TGx 996-26E, grown in a field with a heavy epidemic of frogeye leaf spot caused byCercospora sojina, were treated with double foliar applications of the fungicide benomyl. The treatments were made using four application schedules at six different growth stages, starting from V₃ (fully developed leaves, beginning with trifoliate nodes) to R₅ (beginning seed_, to determine the effect of the fungucide timing on frogeye leaf spot severity, soybean grain yield and grain quality. Generally, applications at R₁ (beginning bloom) and R₃ (beginning pod) significantly (P<-0.05) reduced disease severity in the 2 susceptible genotypes, Samsoy 1 and TGx 849-313D. Plot yields of these genotypes were also significantly greater than the untreated controls when the fungicide applications were made at R₁ and R₃. There was no significant difference in diseave severity or grain yield, between the untreated control and the different times of application, on the resistant genotype TGx 996-26E. Improved seed germination and lower levels of seed infection byC. sojina occurred for all fungicide timings in the susceptible genotypes. The results suggest that fungicide spraying initiated at R₁ and followed up at R₃ is most effective in frogeye leaf spot control and can also result in higher grain yields, than applications made earlier or later in the season. Control of frogeye leaf spot, however, is best achieved by growing resistant cultivars.     

茼蒿叶斑病病原菌的鉴定及室内药剂筛选

茼蒿是上海地区设施叶菜主要种类之一?近年来, 上海市部分地区的茼蒿上出现了一种叶部病害, 叶片出现外缘灰褐色?中央灰白色的圆形病斑, 严重影响茼蒿产量与商品质量?本文采用组织分离法进行病原菌的分离纯化, 通过柯赫氏法则验证?形态学?生物学特性以及基于核糖体转录间隔区(internal transcribed spacer, ITS)?真核翻译延长因子1α (translation elongation factor, TEF)?钙调蛋白 (calmodulin, CAL) 基因和肌动蛋白 (actin, ACT) 基因联合系统发育分析等方法进行了病原菌鉴定, 结果表明, 茼蒿叶斑病的病原菌为芹菜尾孢Cercospora apii, 菌丝生长最适温度为26℃, 复合氮源利于菌丝的生长?杀菌剂的离体抑菌活性测定结果表明:己唑醇?苯醚甲环唑?戊唑醇?氟环唑?嘧菌酯的EC50分别为0.042 3?0.060 4?0.317 4?0.452 4?0.863 3 μg/mL, 对该病原菌菌丝生长表现出较强的抑制作用?这些结果为小宗作物病害的防控或杀菌剂登记提供重要依据?