Identification of race 2.5 of leaf mold (Passalora fulva,syn. Cladosporium fulvum) on tomato

Journal of Plant Diseases and Protection - Leaf mold caused by the fungus Passalora fulva has been a serious disease in greenhouse tomatoes in Turkey. This study was conducted to determine races of...     

电生功能水对保护地番茄叶霉病防治效果

弱酸性电生功能水处理保护地越冬番茄,每15 d喷洒一次,喷洒量80 mL/m2,连续处理3次。结果表明,电生功能水对番茄叶霉病防治效果达68.1%,喷洒条件相同的甲基硫菌灵和恶唑菌酮·氟硅唑的防治效果仅为30.4%,即电生功能水对番茄叶霉病的防治效果比混合农药高1倍以上。本研究结果为电生功能水作为绿色杀菌剂在农业上的应用提供了依据。     

浙南菜区番茄曲叶病毒病发生规律

通过两年调查,明确了浙南菜区越冬番茄曲叶病毒病的主要侵染期在9月下旬至10月上旬,即番茄苗龄20~30 d。温州近郊常年蔬菜生产基地,番茄曲叶病毒病的侵染循环主要通过携毒烟粉虱在越冬番茄和早春番茄间传播完成。苍南、瑞安等季节性番茄生产基地,该病的侵染循环主要通过携毒烟粉虱在越冬番茄、大田番茄苗和夏季南瓜等中间寄主传播完成。随着播种期推迟,番茄曲叶病毒病发生轻,目前浙南菜区生产上‘托马雷斯’、‘好韦斯特’、‘合作903’等主栽番茄品种均表现感病。田间调查还表明,通过50目防虫网覆盖育苗栽培可以有效控制番茄曲叶病毒病发生,防控效果达到90%以上。     

Spatiotemporal distribution of tomato plants naturally infected with leaf mold in commercial greenhouses

The distribution of tomato plants infected by Passalora fulva, causal agent of leaf mold, was analyzed by using Taylor’s model and Iwao’s model to assess the patterns of spatial distribution within the greenhouses. In Taylor’s model, the sample variance (s ²) of diseased plants newly recognized at each observation increased only slightly with mean density (m). In Iwao’s model, the mean crowding (m*) of newly recognized diseased plants at each observation increased with m of diseased plants. The statistical analysis in this study suggests that new infections in greenhouses observed during this investigation tended to cluster around a diseased plant and that secondary infections occurred as independent cluster points.     

番茄与叶霉菌互作的分子机理

 番茄和叶霉菌(Cladosporium fulvum Cooke)系统是研究植物和病原物互作分子机理的模式系统。4个叶霉菌无毒基因已被克隆。这些无毒基因编码含偶数个半胱氨酸的小分子量蛋白,在叶霉菌毒性菌株中的存在与否及存在方式各不相同。Avr4具有几丁质结合活性;而Avr9可能在叶霉菌氮素代谢中起调节作用。7个具有功能的番茄抗叶霉菌Cf基因已被克隆。它们与其同源基因一起以基因簇形式存在于复合基因座中,其成员称为Hcr (homologues of C. fulvum resistance gene Cf)基因。Cf蛋白定位于细胞质膜,但主体在膜外,主要结构域为富含亮氨酸重复(LRR)和跨膜结构域。LRR重复单元数目以及N端序列决定了Cf蛋白对Avr的识别特异性。Cf对Avr的识别遵守"保卫"假说。在Cf-2对Avr2的识别系统中,蛋白酶Rcr3为"被保卫"蛋白。Cf识别Avr后迅速激活下游信号传导和防卫反应,包括过敏性反应的产生和氧化迸发,以及K⁺离子通道、各类蛋白激酶、SGT1、硫氧还蛋白及磷脂酸途径的活化。温度、湿度和光照等环境条件显著影响Cf介导的过敏性反应和抗病性。不同Cf对Avr的识别机理及其下游信号传导途径有显著差别。     

The first report on the occurrence race 9 of the tomato leaf mold pathogen Cladosporium fulvum (syn. Passalora fulva) in Cuba

Leaf mold caused by the fungus Cladosporium fulvum (syn. Passalora fulva) has been a serious disease in greenhouse tomatoes in Cuba, but less damage is seen in outdoor grown plants. This study was conducted to identify races of the causal agent of tomato leaf mold. A total of 36 single conidial isolates obtained from different provinces in Cuba and the reference strain race 0 were inoculated on a differential set of tomato cultivars carrying different Cf resistance genes. Further, a polymerase chain reaction (PCR) was developed using Avr9 gene-specific primers. As result, all isolates could overcome the Cf-9 resistance gene only, but not resistance genes Cf-2, Cf-4 and Cf-5 and must therefore be coined race 9. Race identity was also confirmed by PCR analysis, which showed that the Avr9 gene was not amplified in any of 36 single conidial isolates studied proving that they all lack this gene. This is the first report of the occurrence of race 9 of C. fulvum in Cuba. Pyramiding other Cf genes in hybrid of tomato may provide a more durable level of resistance to C. fulvum.

     

2009年河北省番茄黄化曲叶病毒病发生危害和分布

2009年,河北省主要番茄种植区发生一种疑似番茄黄化曲叶病毒病的新病害。本文在田间调查、取样的基础上,采用酶联免疫吸附测定(ID-ELISA)方法对病原进行鉴定,明确了番茄黄化曲叶病在河北省的分布与危害:至2009年9月,番茄黄化曲叶病毒病已在河北省南部的邯郸、邢台和石家庄,中部的保定和衡水等地严重发生,河北省中北部廊坊、沧州南部靠近衡水的部分地市亦零星发生此病害,应用TYLCV检测试剂盒检测的29个品种58个标样A405值达到2.1～7.5。唐山、承德地区尚未发现番茄黄化曲叶病的危害,4个县市9个番茄品种检测结果均呈阴性。     

番茄叶霉病菌对氟唑菌酰羟胺敏感基线的建立及氟唑菌酰羟胺田间防病效果评价

氟唑菌酰羟胺(pydiflumetofen)是一种新型SDHI类杀菌剂,目前在中国仅登记用于防治小麦赤霉病和油菜菌核病,为明确其对番茄叶霉病的防治潜力,测定了番茄叶霉病菌Passalora fulva不同发育阶段以及山东省不同地区采集的菌株对氟唑菌酰羟胺的敏感性,并验证了其田间防治效果.结果表明:氟唑菌酰羟胺对番茄叶霉...     

Leaf mold of tomato caused by races 4 and 4.11 of Passalora fulva in Japan

Leaf mold of tomato was found on cv. Momotaro-fight in 2003 in Ehime Prefecture. The symptoms were marginal indefinite yellowing on the upper leaf surface, and downy, gray to brown sporulation on the lower surface underneath the spots. The symptoms and morphology were the same as seen with Passalora fulva. The fungal isolates were identified as races 2.4, 2.4.11, 4, and 4.11 by inoculation tests. Races 4 and 4.11 have never before been found in Japan.     

加工番茄叶霉病的防治药剂筛选及其品种抗性鉴定

本研究针对加工番茄叶霉病菌进行了药剂室内毒力测定和盆栽防效试验,并对14份加工番茄品种抗叶霉病进行了评价,目的是筛选出对加工番茄叶霉病具有良好防效的药剂和抗病品种。结果表明:30%烯酰·咪鲜胺SC抑菌效果最好,其EC50为0.006mg/mL。防效试验中,5种药剂均有一定的抑菌效果;22.5%异菌脲SC、56.7%氢氧化铜WG、47%春雷王铜WP和30%烯酰·咪鲜胺SC对叶霉病的防效均在60%以上。供试的14份加工番茄品种中,没有发现高抗品种,中抗品种4个,感病品种8个,高感品种2个。‘屯河9号’、‘石红666’、‘金红宝87-5’和‘737’为中抗品种,‘石红18’和‘石红45’为高感品种,其余为感病品种。     

Occurrence of a new resistant breaking pathotype of Meloidogyne incognita on tomato in Greece

Journal of Plant Diseases and Protection - In a pot assay, a population of Meloidogyne incognita from Northern Greece, reproduced on the resistant tomato cv. Silvana carrying the Mi gene and on...     

Race 2.5, a new race of Cladosporium fulvum (Fulvia fulva) on tomato

Samenvatting VanCladosporium fulvum, de veroorzaker van bladvlekkenziekte van tomaat, zijn talrijke fysio's bekend. Van tomaterassen met resistentiegen Cf5 werd, zowel bij materiaal uit Bulgarije als uit Frankrijk, een nieuw fysio, 2.5, geïsoleerd. Dit bezit naast het noodzakelijke virulentiegen 5 ook het overbodige gen 2. Dit is wéér een voorbeeld van afwezigheid van stabilising selection.     

Occurrence of a new leaf spot disease ofMusa sp. incited byThanatephorus cucumeris

A new leaf spot disease of banana(Musa sp.) cv. ‘Rasthali’ (syn. Silk) was observed in Tamil Nadu, in 1987. The causal organism was isolated in pure culture and identified asRhizoctonia solarii Kühn. The teleomorphic stage,Thanatephorus cucumeris (Frank) Donk, has also been induced artificially. This is the first record of this pathogen causing leaf spot disease onMusa sp. The pathogenicity of basidiospores on several other important crops was also tested.     

西昌地区石榴叶霉病的病原鉴定

本文报道了四川西昌市发生的石榴叶霉病的症状及病原鉴定结果。叶霉病发生在石榴生长后期,一般危害石榴老叶,表现为黑褐色病斑,造成石榴提早落叶。病原分离采用组织分离法,通过分生孢子悬浮液接种,用柯赫氏法则对其致病性进行验证。显微镜下观察菌丝形态及产孢结构,测量孢子大小,根据形态特征鉴定为极细枝孢（Cladosporium tenuissimum Cooke）。     

Occurrence of a new powdery mildew of greenhouse tomato in Greece, caused by Erysiphe sp.

An epiphytic pathogen causing powdery mildew on greenhouse-grown tomato (Lycopersicon esculentum) appears for the first time in Greece and is identified as belonging to the genus Erysiphe.     

Race 2.5.9, a new race of Cladosporium fulvum (fulvia fulva) and sources of resistance in tomato

Samenvatting Cladosporium fulvum staat bekend om zijn vermogen zich snel aan te passen aan nieuw geïntroduceerde resistentiegenen. Die laatste jaren bleven tomaterassen met C5 resistentie in de praktijk resistent. Deze rassen zijn zelfs resistent tegen het complexe fysio 2.4.5 door het bezit van Cf9 of een ander resistentie-gen. Een fysio 2.4.5.9 trad weliswaar op bij proeven op het IVT (Wageningen), maar werd nooit in de praktijk gevonden.In 1985 werd in Frankrijk het ras Rianto F1 in een praktijkteelt aangetast. Een isolaat vanC. fulvum van dit C5-resistente ras bleek fysio 2.5.9 te zijn. Een deel van de thans bij onderzoek gebruikte resistentiebronnen, zoals Bulgaria no. 1, Japan 74S en Japan 76S, is resistent voor dit nieuwe fysio.Het optreden van dit nieuwe fysio onderstreept de wenselijkheid ten minste twee nieuwe resistentiegenen in nieuwe rassen te gebruiken ter verbetering van de duurzaamheid van de resistentie.     

Occurrence of azoxystrobin‐resistant isolates in Passalora fulva,the pathogen of tomato leaf mould disease

Since 2007, serious damage to tomato from leaf mould caused by Passalora fulva has frequently been observed in commercial greenhouses in Gifu Prefecture, Japan. One of the factors relating to this damage was suspected to be a decrease in azoxystrobin sensitivity of the pathogen. Biological and molecular studies were conducted to characterize fungicide resistance. In in vitro sensitivity tests using mycelial homogenate placed on fungicide‐amended medium, the minimum inhibitory concentrations (MIC) of azoxystrobin for mycelial growth of the isolates divided into two ranges, 0.031–0.5 mg L^?1 and 8–32 mg L^?1. Isolates with MICs within the two ranges were considered as sensitive and resistant, respectively, to azoxystrobin because, in in vivo tests, the percentage protection conferred by this fungicide (100 mg a.i. L^?1) against these isolates was 89.7–100% and 4.5–31.1%, respectively. Resistant isolates had a replacement of phenylalanine with leucine at codon 129 (F129L) in cytochrome b. Forty‐five percent of the 271 isolates collected from 63 tomato greenhouses from 2007 to 2008 were resistant to azoxystrobin. In many greenhouses where the isolation frequency of resistant isolates was 80% or more, azoxystrobin had been used twice per crop for approximately 6 years. In 2012, 27% of the 405 isolates collected were resistant to azoxystrobin, and there was a marked difference in the frequency of occurrence of resistant isolates in the field populations between the three locations sampled. The occurrence of azoxystrobin‐resistant P. fulva isolates (F129L mutants) inflicted considerable damage on greenhouse tomatoes.