广西茄子主要病害诊断及防治技术（二）

6茄子白粉病 6.1病害症状 主要为害叶片。叶面初现不定形褪绿小黄斑,相应的叶背面则出现不定形白色小霉斑,边缘界限不明晰,仔细观察,可见霉斑近乎放射状扩展。随着病情的进一步发展,叶面不规则形白粉状霉斑增多,斑面上白色粉状物日益明显,粉斑相互连合成白粉状斑块,扩展后白粉病斑遍及整个叶面,     

酿酒葡萄霜霉病综合防治措施

1症状葡萄霜霉病主要危害葡萄叶片,同时还侵害嫩梢、花序和幼果等幼嫩部分和成熟果实。叶片感病后,病斑最初为细小的不规则淡黄色水渍状斑点,以后逐渐扩大,在叶片正面出现黄斑,天气潮湿时,叶背面形成白色的霜状霉层,受害葡萄叶面形成黄色或褐色多角形病斑,发病严重时,叶片焦枯卷缩,     

日光温室红地球葡萄主要病害发病规律及防治方法

1葡萄白粉病 葡萄白粉病是我县发生的一种干旱性病害。 1．1症状主要危害叶片、新梢及果实等幼嫩器官，老叶及着色果实较少受害。葡萄展叶期叶面或叶背产生白色或褪绿小斑，病斑渐扩大，表面长出粉白色霉斑，严重的遍及全叶，致叶片卷缩或干枯。     

甜瓜白粉病综合防治

<正>1症状主要危害叶,也侵染叶柄、瓜蔓和瓜。叶片发病初期,叶面产生近圆形白色小霉点(即病原菌菌丝和分生孢子),后扩大成霉斑。条件适宜时,霉斑迅速扩大,彼此连成片,白粉状物会布满整个叶片,叶片变脆。后期病斑上霉状物变成灰白色,其上长出黑色小点,即病菌的闭囊壳。发病重的,叶片出现不规则黄褐斑,病斑连片致整个叶片变褐干枯,但不脱落。叶柄、瓜蔓和瓜染病,亦产生白色粉斑,发展后病部布满白粉。     

白菜霜霉病综合防控

1为害症状白菜霜霉病,是在白菜种植期间常见的真菌病害。子叶期发病时,叶背出现白色霉层,在高温条件下,病部常出现近圆形枯斑,严重时茎及叶柄上也产生白霉,苗、叶枯死。成株期,叶正面出现淡绿至淡黄色的小斑点,扩大后呈黄褐色,病斑受叶脉限制,呈多角形,潮湿时叶背面病斑上生出白色霉层;白菜进入包心期,条件适宜时,叶片上病斑增多并联片,叶片枯黄,病叶由外叶向内叶发展,严重时植株不能包心。     

红提葡萄霜霉病的发生与防治

<正>1发病症状葡萄霜霉病主要危害葡萄叶片,同时还侵害嫩梢、花序、幼果等幼嫩部分及成熟果实。叶片感病后,病斑最初为细小的不规则淡黄色水渍状斑点,以后逐渐扩大,在叶片正面出生黄斑,天气潮湿时,叶背面形成白色的霜状霉层,受害葡萄叶面形成黄色或褐色多边形病斑,发病严重时,叶尾焦枯卷缩,提早脱落。受害青果皱缩干枯,色暗红或褐红,病粒果肉里出现黑褐     

大白菜三大病害的危害与防治

1 霜霉病 1.1 危害症状主要危害叶片.苗期发病,初期叶正面出现淡绿色斑点,扩大后变黄,叶背面出现白色霉状物,严重时苗叶及茎变黄枯死.成株期发病,叶背面现白色霜霉,叶正面出现淡绿色的病斑,并逐渐转变为黄色至黄褐色.病斑扩大常受叶脉限制呈多角形.一般接近地面的叶片发病早,并由下向上发展.     

蔬菜霜霉病的识别与防治

霜霉病是一种常见的蔬菜病害,主要为害瓜类蔬菜、十字花科蔬菜及绿叶蔬菜等,一般情况下可造成减产20％～30％,严重时可造成减产50％以上. 1症状识别 霜霉病是由真菌中的霜霉菌引起的植物病害,从幼苗到收获各阶段均可发生,以成株受害较重.主要为害叶片,由基部向上部叶发展.不同蔬菜症状不完全相同,总体表现为病斑初呈水浸状,扩展后受叶脉限制,形成多角形或不规则形黄褐色斑块.空气潮湿时叶背产生霜状霉层,为病菌的孢囊梗和孢子囊,有时可蔓延到叶面,其中在瓜类上为灰黑色霉层,在白菜和菜薹等十字花科蔬菜上为白色霉层,在菠菜上为灰白色至灰紫色霉层,在莴苣上为白色霉层.后期病斑枯死连片,呈黄褐色,严重时全部外叶枯黄死亡.     

萝卜六种常见病害的发生与防治措施

1萝卜霜霉病该病是由真菌引起的。1.1发病症状：全生育期均可发病,从植株下部向上扩展。发病初期叶片产生淡绿色水浸状小斑点,扩大后病斑受叶脉限制形成多角形或不规则形的淡黄色至黄褐色病斑,直径3～7毫米。湿度大时,叶背或叶两面长出白霉。病斑连片可引起叶片干枯。茎部发病出现黑褐色不规则状斑点。根部发病受害部位表面产生灰褐色或灰黄色稍凹陷的斑痕,贮藏时极易引起腐烂。采种株受害主要危害种荚,产生淡褐色不规则形病斑,上有白色霉状霉层。     

柑桔白粉病的发生规律及防治技术

近年 ,柑桔白粉病在重庆市五桥各柑桔产区有加重趋势 ,造成减产 1 0 % ,重者可达 30 %以上。为有效控制该病为害 ,1 997年以来我们开展了柑桔白粉病发生规律及防治技术的研究 ,取得了一定经验 ,现总结如下。1　为害症状　　白粉病主要为害柑桔新梢、嫩叶及幼果。嫩叶上病斑为白色霉斑 ,呈绒毯状。霉斑在嫩叶正反两面均可产生 ,大多近圆形。霉斑常由中心向外扩展。霉层下面叶肉组织开始呈水渍状 ,以后逐渐失绿 ,呈褐色 ,叶肉组织背面呈黄色。严重时霉层覆盖整个叶片 ,造成叶片皱缩、畸形 ,落叶。叶片老化后 ,病部白色霉层转为浅灰褐色。嫩枝…     

葡萄霜霉病症状及综合防治技术

阐明了葡萄霜霉病的表现症状,发生规律。提出了综合防治措施。     

南瓜白粉病研究进展

南瓜白粉病是南瓜作物生产上最主要的病害之一,严重影响南瓜的产量和品质,制约产业的经济效益和瓜农生产积极性。目前,国内外对南瓜白粉病菌研究较少,对南瓜白粉病的防治手段较为单一。笔者过对国内外南瓜白粉病的发病规律、抗白粉病种质资源现状、分子生物学研究现状、白粉病防治等方面的研究结果进行综述,以期为南瓜生产和白粉病防治相关研究提供参考。     

板栗贮藏中霉烂原因及预防措施

板栗属干果,普遍认为比水果耐贮藏运输。实际上,栗果内部的特殊结构决定了在贮藏和运输中的生理变化。板栗与其他干果不同,失水风干即失去生命力、失去鲜食价值。因此,板栗在贮藏中既怕干、怕水、怕热又怕冻,一旦处理不当,大量烂果。从总体上说,晚熟品种比早熟品种耐贮,可能与板栗的内部生理机制、外部的温度条件和坚果本身的含水量有关。     

甜瓜抗白粉病育种研究进展

综述了葫芦科白粉病菌的种类、特征及其分布,重点介绍了主要危害葫芦科作物的2个白粉病的特点和其鉴定,甜瓜白粉病菌生理小种的分化和通用甜瓜鉴别寄主对这些不同生理小种的抗感反应,对抗源的发掘、抗性遗传与抗病育种进行了详细的评述,并提出了今后我国甜瓜白粉病研究的方向。     

梨白粉病防治技术要点

梨白粉病(Phyllactinia pyri[Cast]Homma)主要危害叶片,在河北、辽宁、山西、陕西等地梨产区常有发生,严重时造成早期落叶。与梨黑星病、梨黑斑病相比,梨白粉病的发生一直未被重视。随着环境条件的改变,病害的危害也发生变化。在河北省冀东地区,春季梨白粉病较少发生,主要发生在秋季,生产中主要集中在果实采收前防治,多数梨园在果实采收后对白粉病的防治不够重视。近年来常出现高温干旱天气,使得梨白粉病的发生呈逐年加重的趋势,大量梨树发生早期落叶,造成二次发芽,对产量、树势影响极大。已成为梨树主要病害之一。     

杂交榛子对白粉病的抗性及防治技术研究

榛子白粉病是一种真菌性病害,主要危害榛树的嫩叶和果苞。近年来发生逐渐加重,若不及时防治,常引起树体营养贮藏少,树势衰弱,花芽分化差,     

Effectiveness of whey against zucchini squash and cucumber powdery mildew

The effectiveness of whey against powdery mildew (Podosphaera xanthii) of cucumber and zucchini squash was tested in greenhouse experiments. Plants were sprayed once or twice a week with whey at concentrations of 0, 5, 10, 15, 20, 25, and 30% in water. Severity of powdery mildew was estimated weekly by visual assessment of individual leaves and scored as percentage of leaf area affected. Effectiveness of treatments did not differ significantly when applied weekly compared to twice a week. In each instance, powdery mildew severity correlated negatively with whey concentration. For cucumber, the rate of the disease progress in the control ranged from 0.45 to 0.75. Disease progressed more slowly in plants treated with 25–30% whey than when lower concentrations were used. The rate of disease progress varied from 0.12 to 0.33 in plants treated once a week and from 0.13 to 0.17 when applied twice a week. Similar tendencies were observed for zucchini, but disease progressed more rapidly and the final disease severity was higher than in cucumber. Effectiveness of whey applied twice a week at concentrations of 15–30% did not differ significantly among treatments; in these treatments the rate of disease progress was about 0.23 and significantly higher than the value for the water controls (about 0.80). Plants treated with 30% whey often exhibited symptoms of phytotoxicity. The data indicated that whey effectively controlled powdery mildew in cucumber and zucchini. Further studies are needed to optimize the concentration and timing of whey applications for mildew management in commercial crops.     

Genetic basis of powdery mildew resistance in muskmelon

A study was undertaken to investigate the inheritance of powdery mildew resistance in muskmelon grown on river beds, under natural epiphytotic conditions. ‘Campo’ and ‘PMR 6’ were selected as resistant parents, ‘Gulfstream’ as moderately resistant and ‘Lucknow Safeda Selection’ as susceptible parents. The genotypes of the two resistant parents have locus/loci which are similar in conferring resistance. The moderately resistant parent might have an allele at least in one locus different from that in the resistant parent. Two effective factors were found to be differentiating disease reaction between the susceptible and the resistant parents. The direction of the genetic effects showed that it is possible to get from the cross between the susceptible and resistant parents, segregants with the desired level of resistance.     

温室草莓白粉病防治技术

草莓作为经济价值较高的小浆果,因其味美营养价值高．深受人们喜爱。目前我国草莓的栽培面积已达6万hm^2,位居世界第1位。近年来,温室草莓白粉病发病强度呈逐年加重的趋势．一经发生很难防治,一般减产20％～30％,重者可达50％．严重影响草莓的产量和品质．已经成为我省温室草莓生产的重要病害。     

Rapid quantification of plant-powdery mildew interactions by qPCR and conidiospore counts

ABSTRACT: BACKGROUND: The powdery mildew disease represents a valuable patho-system to study the interaction between plant hosts and obligate biotrophic fungal pathogens. Numerous discoveries have been made on the basis of the quantitative evaluation of plant-powdery mildew interactions, especially in the context of hyper-susceptible and/or resistant plant mutants. However, the presently available methods to score the pathogenic success of powdery mildew fungi are laborious and thus not well suited for medium- to high-throughput analysis. RESULTS: Here we present two new protocols that allow the rapid quantitative assessment of powdery mildew disease development. One procedure depends on quantitative polymerase chain reaction (qPCR)-based evaluation of fungal biomass, while the other relies on the quantification of fungal conidiospores. We validated both techniques using the powdery mildew pathogen Golovinomyces orontii on a set of hyper-susceptible and resistant Arabidopsis thaliana mutants and found that both cover a wide dynamic range of one to two (qPCR) and four to five (quantification of conidia) orders of magnitude, respectively. The two approaches yield reproducible results and are easy to perform without specialized equipment. CONCLUSIONS: The qPCR and spore count assays rapidly and reproducibly quantify powdery mildew pathogenesis. Our methods are performed at later stages of infection and discern mutant phenotypes accurately. The assays therefore complement currently used procedures of powdery mildew quantification and can overcome some of their limitations. In addition, they can easily be adapted to other plant-powdery mildew patho-systems.