2017年河南省小麦纹枯病菌对三唑酮的敏感性

为监测中国河南省小麦纹枯病菌对三唑酮的敏感性,采用菌丝生长速率法测定了三唑酮对从河南省15个地市分离的169株病菌的毒力。结果显示:供试菌株对三唑酮的EC₅₀值在0.82~12.62 μg/mL之间,敏感性差异达到15.39倍,平均EC₅₀值为 (3.33 ± 1.91) μg/mL。敏感性频率分布图显示:169株小麦纹枯病菌对三唑酮的敏感性呈连续性分布,部分供试菌株的EC₅₀值已超出敏感性基线范围;39.6%的菌株(67株)集中位于敏感性频率分布图主峰范围内,呈近似正态分布,EC₅₀平均值为 (1.78 ± 0.44) μg/mL;最小显著差异法(least significant difference, LSD)与聚类分析均表明,不同地区菌株对三唑酮敏感性差异不明显,病菌对三唑酮的敏感性差异与菌株来源的地理位置无明显相关性;河南省各地市菌株对小麦纹枯病菌的抗药性倍数和频率不同,可以据此指导各地的用药选择。     

三唑酮、三唑醇对小麦纹枯病菌形态和生理的影响

 小麦纹枯病菌(Rhizoctonia cerealis)在加入三唑酮(Triadimefon)或三唑醇(Triadimenol)的培养液中生长时,菌丝形态和生理发生明显的改变。菌丝畸形,表现为细胞肿大,细胞分隔处菌丝缢缩;药剂处理后,等量菌丝的麦角甾醇含量下降,1、5μg/ml的三唑酮和三唑醇处理,麦角甾醇含量比对照减少45.155.9%和27.5、48.9%;菌丝在药剂处理后,电解质渗漏增加,5μg/ml药剂处理一小时后,三唑酮组的菌丝之细胞电解质渗漏达2.58%,三唑醇组的渗漏为2.19%,空白对照组仅为0.65%。本研究结果表明,三唑酮、三唑醇对小麦纹枯病菌具有直接的伤害作用。     

小麦纹枯病菌对三唑酮不同敏感性菌株的生物学特性及对不同杀菌剂的敏感性

为预测小麦纹枯病菌对三唑酮抗药性的发展趋势,采用菌丝生长速率法测定了2013年分离自河南省16个地市的98株菌株对三唑酮的敏感性,比较不同敏感性菌株的生物学性状差异,并分析了其中22株菌株对其它10种杀菌剂的敏感性。结果表明:小麦纹枯病菌群体中已出现对三唑酮敏感性下降的菌株,其中有90株菌对杀菌剂的敏感性属于正态分布,以其EC_(50)均值1.91μg/mL作为小麦纹枯病菌对三唑酮的敏感性基线。敏感菌株菌丝生长速度较快,可达8.50~12.86 mm/d,菌核产量较多,为35.80~42.90 mg/皿,生存适合度较高;敏感性下降及抗性菌株的致病性及菌核萌发等都未发生改变,但菌丝生长速率仅为5.36~10.02 mm/d,菌核产量为9.00~36.90 mg/皿,均下降明显,生存适合度降低;低抗菌株与敏感菌株在菌落形态上相同,但菌丝分枝数增多且分枝菌丝变短。三唑酮对小麦纹枯病菌的毒力较小,EC_(50)大于其它10种杀菌剂;戊唑醇、氟环唑、烯唑醇、咯菌腈和噻呋酰胺的毒力均较大,其EC_(50)≤0.10μg/mL;其余5种杀菌剂的EC_(50)在0.13~0.69μg/mL之间;小麦纹枯病菌对三唑酮的敏感性与其它10种杀菌剂间的决定系数为0.003~0.200,存在微弱的正相关性,表明在生产中这些杀菌剂可与三唑酮轮换或交替使用。     

中国河南省小麦纹枯病菌对咯菌腈的敏感性

为明确河南省小麦纹枯病菌对咯菌腈的敏感性,采用菌丝生长速率法测定了咯菌腈对2013年从河南省15个地市分离的98株病菌的毒力。结果表明:咯菌腈对供试小麦纹枯病菌菌株的EC50值在0.009~0.079 μg/mL之间,平均EC50值为(0.025 ±0.012)μg/mL;98个菌株对咯菌腈的敏感性分布呈连续单峰曲线,未出现敏感性下降的亚群体,可将(0.025 ±0.012)μg/mL作为小麦纹枯病菌对咯菌腈的敏感性基线;方差分析(LSD法)及SPSS聚类结果均显示,同一地市内的菌株对咯菌腈的敏感性差异较大,EC50最大值和最小值之比在1.0~4.1之间,而不同地区菌株间对咯菌腈敏感性差异不明显,咯菌腈EC50平均值变化范围在0.015~0.060 μg/mL之间,后者是前者的4倍;小麦纹枯病菌对咯菌腈的敏感性与其对噻呋酰胺、苯醚甲环唑、井冈霉素、丙环唑及戊唑醇的敏感性之间无明显相关性。本研究结果可为河南省小麦纹枯病防控杀菌剂的合理使用提供理论依据。     

中国河南省小麦纹枯病菌对井冈霉素及甲基立枯磷的敏感性

为明确中国河南省小麦纹枯病菌对井冈霉素及甲基立枯磷的敏感性,采用菌丝生长速率法测定了两种药剂对采自该省15个地市的98株病原菌菌丝生长的毒力。结果显示:井冈霉素和甲基立枯磷对供试菌株的EC₅₀值范围分别在0.023~0.852和0.035~0.512 μg/mL之间;其敏感性频率分布图显示,病原菌群体中虽已出现对井冈霉素敏感性下降的亚群体,但77.6%和99.0%的菌株对井冈霉素和甲基立枯磷的敏感性频率仍呈正态分布,因此可将此部分菌株的平均EC₅₀值（0.424±0.081）和（0.124±0.043）μg/mL分别作为小麦纹枯病菌对井冈霉素和甲基立枯磷的敏感基线;井冈霉素的平均EC₅₀值是甲基立枯磷的3倍,表明该病原菌对甲基立枯磷更为敏感;不同地理来源病原菌群体间对井冈霉素和甲基立枯磷的敏感性均存在显著的地域性差异;小麦纹枯病菌对两种杀菌剂的敏感性之间无明显相关性。研究结果可为河南省小麦纹枯病的可持续防控提供理论依据。     

中国河南省小麦纹枯病菌对苯醚甲环唑及戊唑醇的敏感性

为明确中国河南省小麦纹枯病菌对苯醚甲环唑及戊唑醇的敏感性,采用菌丝生长速率法测定了2种药剂对采自河南省15个地市分离的95株病菌的毒力。结果显示:供试菌株对苯醚甲环唑和戊唑醇的EC50值分别在0.014~1.609和0.002~0.064 μg/mL之间。敏感性频率分布图显示:在小麦纹枯病菌群体中已出现对苯醚甲环唑敏感性下降的亚群体,而对戊唑醇则不明显;可将其中呈连续单峰频次分布的大多数菌株群体的平均EC50值（0.165±0.101）和（0.019±0.008）μg/mL分别作为小麦纹枯病菌对苯醚甲环唑和戊唑醇的相对敏感基线。苯醚甲环唑的平均EC50值是戊唑醇的26倍,表明该病原菌对戊唑醇更为敏感。不同地区病原菌群体间对苯醚甲环唑和戊唑醇的敏感性均存在显著性差异。小麦纹枯病菌对2种杀菌剂的敏感性之间存在着微弱的正相关性。本研究结果可为河南省小麦纹枯病防控杀菌剂的合理使用提供理论依据。     

山东小麦纹枯病的发生及防治

小麦纹枯病（Ｒｈｉｚｏｃｔｏｎｉａｃｅｒｅａｌｉｓ）是一种以土壤传播为主的真菌病害。随着种植制度的改革,高产品种的推广和水、肥、密度的增加,危害日趋严重。山东省１９９１年发病率高达７８．３％,一般病田造成减产９％～１０％左右,严重地块可达８５％以上。一、小麦纹枯病的病原及危害小麦纹枯病菌的寄主范围广,除侵染小麦以外,还可侵染玉米、水稻、谷子、高梁等多种作物和狗尾草、蟋蟀草、马唐、稗草等禾本科杂草。该病的病原菌主要是禾谷丝核菌（Ｒｈｉｚｏｃｔｏｎｉａｃｅｒｅａｌｉｓ）中的第一菌丝融合组（ＣＡＧ—１…     

河南省小麦纹枯病菌对三唑酮的敏感性

正小麦纹枯病是一种世界分布的土传真菌病害。近年来该病在我国冬小麦种植区发生普遍,已成为小麦高产、稳产的重大障碍~([1])。河南省是我国小麦主产区之一,近几年小麦纹枯病的发生面积连续在300万hm~2左右,危害严重~([2])。目前,尚未发现高抗纹枯病的小麦品种,控制该病害主要依靠药剂种子处理结合春季喷雾来进行,所用药剂包括井冈霉素和以三唑酮为代表的三唑类化学药剂。随着     

四地区小麦纹枯病菌对6种杀菌剂的抗性比较

从山东和江苏的4个小麦产区采集分离了5个小麦纹枯病菌Rhizoctonia cerealis菌株，为明确小麦纹枯病菌对不同杀菌剂的抗性现状，采用生长速率法测定了5个小麦纹枯病菌菌株对三唑酮、井冈霉素、戊唑醇、咯菌腈、丙环唑、苯醚甲环唑6种常用杀菌剂的抗性。结果表明：江苏镇江菌株（JZ）对三唑酮和井冈霉素的抗性分别高达20．46和23．31倍，山东聊城2个菌株（L1和L2）和泰安菌株（TA）对三唑酮的抗性分别为14．26、10．10和11．98倍，滕州菌株（聊）和泰安菌株（TA）对井冈霉素的抗性分别为14．92和10．46倍。5个菌株对戊唑醇、咯菌腈、丙环唑和苯醚甲环唑抗性均不明显，其中戊唑醇对小麦纹枯病的防治效果最好。     

小麦叶疫病的诊断和病原菌鉴定

小麦叶疫病是由小麦链格孢侵染引起的一种危险性病害。该病典型症状与其他常见小麦叶斑病有明显不同,但发病后期不易区分。本文介绍了该病诊断方法、病原菌鉴定方法及其鉴定标准,说明了该菌与小麦生链格孢以及常见腐生菌细链格孢的形态区别。     

河南省小麦纹枯病菌的群体组成及其致病力分化研究摇

纹枯病已成为我国小麦生产的主要障碍之一.许多学者研究表明,我国小麦纹枯病菌优势菌群为禾谷丝核菌(Rhizoctonia cerealis),其中主要为AG-D融合群,其次还包括AG-A、AG-R、AG-E、AG-Bo融合群和立枯丝核菌(R.solani)的AG-2、AG-4及AG-5融合群等[1].     

几种杀菌剂对小麦纹枯病的防治效果

田间试验结果表明,12.5%烯唑醇可湿性粉剂有效成分110g/hm2、12.5%腈菌唑乳油110g/hm2、10%氯啶菌酯乳油45g/hm2、25%丙环唑乳油180g/hm2对小麦纹枯病有很好的防治效果,防效分别为79.5%、76.3%、65.8%和63.9%,显著优于常用药剂20%井冈霉素水溶性粉剂180g/hm2的防效52.9%,可在生产上大面积推广应用。     

Genetic structure and population diversity in the wheat sharp eyespot pathogen Rhizoctonia cerealis in the Willamette Valley,Oregon, USA

Wheat sharp eyespot, caused by the soilborne basidiomycete fungus Rhizoctonia cerealis group D subgroup I (AG-DI), is a common disease of wheat stems that has increased in global importance in recent years. The disease caused a severe and extensive epidemic throughout the Willamette Valley of Oregon in 2014 and has remained one of the most important wheat diseases in this region subsequently. The population structure of this pathogen is still not well understood. In this study, 572 pure cultures of R. cerealis AG-DI were isolated from five commercial fields and two experimental fields in the Willamette Valley, Oregon, in the spring of 2017 and 2018. Population structure studies were conducted using six microsatellite markers. Polymorphisms were observed at all six loci, and all seven subpopulations showed moderate gene and genotype diversity. Most of the loci were in Hardy–Weinberg equilibrium in the subpopulations, the entire population combined over locations and five of seven subpopulations were in gametic equilibrium, and the AMOVA and Mantel’s test demonstrated no differentiation among subpopulations. Though direct evidence is currently lacking, these results suggest that the sexual stage of the pathogen may be having a significant impact on pathogen population structure, and that the presence of basidiospores could be contributing to the extensive spread of this disease in the Willamette Valley in recent years.     

防治白背飞虱的农药复配增效配方筛选

农药复配制剂的研究对于延长新农药品种的使用寿命、缓解靶标生物的抗性、扩大防治谱、降低防治成本、提高药效和环境安全性等具有重要的意义。为筛选防治白背飞虱的农药增效复配配方,采用稻茎浸渍法测定了8种农药单剂及复配剂对白背飞虱3龄若虫的毒力。利用共毒因子法定性筛选出16组共毒因子大于20的配比,并对其中15组进一步利用共毒系数法定量筛选,得到有增效作用的5组配比,分别为烯啶虫胺与毒死蜱按1∶30配比以及吡虫啉与异丙威分别按7∶40、7∶200、7∶400和7∶1 000配比;其共毒系数分别为112.5、242.1、212.4、638.1、417.7,其中吡虫啉与异丙威按7∶400配比具有最显著增效作用。     

河北省小麦纹枯病菌群体组成及致病力分化

为明确河北省小麦纹枯病发生特点及病菌特征,采用五点取样法调查该病的发生情况,通过细胞核染色、菌丝融合反应和r DNA-ITS序列分析测定196株纹枯病菌群体组成,并比较其对不同小麦品种的致病力差异。结果表明,河北省3个不同生态类型麦区30个监测点均有纹枯病发生,临漳县发病最重,其次是邯郸县和馆陶县,青县发病最轻;纹枯病菌可划分为AG-D、AG-B(0)、AGI、AG-4和AG-5共5种融合群,分别占菌株总数的88.3%、1.5%、5.1%、3.6%和1.5%;采自黑龙港平原区和山前平原区的纹枯病菌对石新828、良星99和邯6172的平均致病力均明显强于冀东平原区;菌株可划分为极强、强、中等和弱4个致病类型,分别占菌株总数的45.92%、33.67%、7.65%和12.76%。表明河北省小麦纹枯病发生普遍,总体呈南重北轻的趋势,纹枯病菌群体组成较简单,以强致病力AG-D融合群为主。     

小麦纹枯病产量损失估计研究

研究了小麦纹枯病病情指数与产量损失率及千粒重的关系。结果表明,产量损失率随着病情指数的增加而增大;千粒重随着病情指数的增加呈下降趋势,并在此基础上组建了病情指数与产量损失率的关系模型,病情指数与千粒重的关系模型。     

The escalating threat of Rhizoctonia cerealis, the causal agent of sharp eyespot in wheat

Rhizoctonia cerealis, the causal agent of sharp eyespot on wheat, was not considered to be an important pathogen for many years. Recently, the disease has become endemic in many countries except for South America. The disease has created a new threat to world wheat production because the damage of wheat sharp eyespot has become increasingly severe. In this paper, previous studies on this pathogen, including the disease geographical distribution, pathogen identification, life cycle, symptoms, favourable environmental conditions, effects on wheat yield and control strategy, are reviewed. Such information will be helpful in management of sharp eyespot.     

小麦纹枯病拮抗细菌的筛选

 从小麦纹枯病病田土壤中分离到722株细菌,通过对峙培养法筛选出拮抗细菌397株,拮抗菌率为55.0%。细菌对小麦纹枯病病原菌的拮抗作用分为两种类型:其一以竞争作用为主,表现为菌株生长快,抑菌率高但抑菌带较窄,如菌株BNT-25抑菌效果可达100.0%,抑菌带仅为2 mm;其二为抗生物质的产生,表现为菌株生长慢,菌落小,抑菌率高且抑菌带宽,如JJ-5菌株抑菌效果可达94.3%,抑菌带为12 mm。选用18株抑菌作用良好的拮抗细菌在室内测定其防治小麦苗期纹枯病的效果。结果发现,与空白对照相比,有9株拮抗细菌的防治效果达到了极显著水平,有15株拮抗细菌的防治效果达到了显著水平。在极显著水平中菌株NZT-47、MTT-8和DHT-12的防治效果分别为76.45%、64.03%和58.89%,对小麦纹枯病表现了较高的防治效果;菌株HNT-7-16、BDT-94和BNT-28的防治效果分别为43.47%、40.97%和40.97%,具有一定的防治作用。其中NZT-47的防治效果最好。     

小麦苗期抗纹枯病鉴定方法的改良及抗病品种筛选

Wheat sharp eyespot, caused by Rhizoctonia cerealis and R. solani, is a soil-borne fungal disease, which poses a great threat to wheat yield. In order to increase the identification efficiency of wheat sharp eyespot resistance, an improved method of rapidly identifying wheat sharp eyespot resistance was established by inoculating wheat seedlings with diseased wheat grains in greenhouse. To verify its reliability, four standard materials and 96 wheat varieties from Huanghuai wheat region were used for resistance assessment to sharp eyespot. Meanwhile, the resistance to Rhizoctonia solani of aforementioned materials in the field was identified by traditional methods. The results showed that the correlation coefficient between the four repetitions of the improved method ranged from 0.735 to 0.825, and the correlation coefficient between the average number of repetitions and the traditional method was 0.630. The results of wheat sharp eyespot resistance identification in Huanghuai wheat area showed that 66 wheat varieties were susceptible, accounting for 68.8% of tested materials. This indicated that the resistance of wheat varieties in Huanghuai wheat area to sharp eyespot was poor on the whole and needed to be improved urgently. At the same time, eleven wheat varieties which showed resistance to sharp eyespot at seedling and adult stages were screened, which include Zhengzhou 8998, Beijing 841, Handan 94-5316, Jimai 32, Jinmai 50, Jinmai 54, Longmai 157, Lumai 23, Shanhe 6, Shi 02-1 and Xinmai 18. Therefore, this study provides a method for identification of wheat sharp eyespot resistance at seedling stage, by which the resistance of wheat varieties to sharp eyespot can be quickly and efficiently identified. Furthermore, selected resistant materials provide important material resources for wheat sharp eyespot resistance breeding in Huanghuai wheat region and even in China.