京郊桃树腐烂病研究

北京1960年普遍发生桃树腐烂病(Leucostoma Spp.),被害株达24—90%。1960—1961年两年来的研究指出:其为害部位,主要集中在主干与主枝上,两者合计占树体病疤总数之80%。其中主干与主枝基部被害尤多。主干症状表现为流胶,内部皮层腐烂呈红棕色,可直达木质部。枝条上虽亦流胶,然在老龄与弱枝上则以长条凹斑形式发展,     

粉锈宁防治苹果梭疤病和白粉病

苹果梭疤病(Cylindrosporium mali)是一种树皮腐烂病害,近年在我国北方苹果产区有发展,大国光等品种感病重,发病后对树势影响较大。一般防治办法是结合果树修剪刮治病部,还可结合其他病害的防治减轻危害。三唑类杀菌剂粉锈宁,对梭疤病有效,可配制成2％糊剂,涂敷伤口。     

2011年烟台苹果产区腐烂病发病情况调查与原因分析

为了解2011年烟台苹果产区腐烂病的发生情况,2011年5月,在腐烂病发病较重的栖霞、海阳等地选择21个农户的果园,对腐烂病的发生情况进行了调查.结果表明,21个果园中具有新病疤的病株率为68.20％,死株率为2.76％,平均受害枝量为23.98％,死枝量10.74％,病株率超过50％的果园占25％～30％,总体发病情况比一般年份严重.调查共发现967块新病疤,平均每株2.32块,其中源自剪锯口的病疤占80.04％,从旧病疤复发的病疤占60.29％.2010年秋季的连续阴雨、冬季低温和2011年春季干旱可能是导致烟台苹果产区2011年春季腐烂病大发生的主要原因.剪锯口是腐烂病菌侵染的主要途径,旧病疤复发是春季腐烂病发病的主体.     

涂抹托福油膏防治苹果腐烂病

苹果腐烂病原仅是我国北方苹果产区的主要病害,在黄河故道新果区则较少成害。但近10年来,腐烂病已迅速蔓延南下,目前已成为我区的重要病害。在防治上,过去一直沿用重刮病疤为主治方法,但是这种方法会增加树体机械损伤,对树体衰弱并多点发病的果树,更造成不良后果。因此,我们试用轻副病疤涂抹托福油膏法。经两年观察,在283块供试病疤中,治疗效果为94.70％。 方法: 在冬季,对病疤上病变组织和翘皮进行轻刮,不必扩伤健皮组织。清理后,随即涂抹1∶1∶8的甲基托布津(70％可湿性粉剂),福美胂(40％可湿性粉剂)和黄油混合油膏(暂名托福油膏)。油膏要搅     

仿生农用杀菌剂银泰对苹果两种主要病害的防治效果

苹果腐烂病和轮纹病是苹果生产上两种重要的病害.苹果腐烂病在山东的发病株率为20%～100%,病情严重的果园,树干上病疤累累、树冠残缺不全、病株寿命缩短,甚至造成死树毁园.苹果轮纹病不仅可以危害枝杆,造成树势衰弱、枝干枯死,还常造成大量烂果,有些年份田间病果率可高达70%～80%,并且在贮藏期可继续发病.长期以来,苹果枝杆上的腐烂病和轮纹病主要以福美胂等药剂进行治疗,虽有一定的防治效果,但防治后的病疤不易愈合,还易得由于砷中毒而引起的粗皮病.果实上苹果轮纹病的防治主要以多菌灵、甲基托布津等药剂进行防治.为了有效地防治这两种病害、提高果品质量和环境安全性、减缓病原菌抗药性的产生,作者根据银杏Gingko biloba L.体内含有大量杀菌物质的报道,经过10余年的研究,从中筛选出了对植物病原真菌有较高生物活性的物质,以其化学结构为先导化合物仿生合成出了新型农用杀菌剂“银泰”.     

双孢蘑菇顶枝孢霉病害的生物学特性和药剂筛选

在双孢蘑菇上发现一种新的病原菌:点枝顶孢菌(Acremonium strictum W.)。该菌侵染双孢蘑菇的子实体,形成不规则的褐色斑块,大小为(2-15)mm×(3-20)mm,病斑凹陷于菌肉或穿过菌肉组织直至菌褶,深达2-13 mmo病斑干枯不腐烂,俗你黑疤病或褐疤病。通过人工接菌观察了病害症状、发病规律、培养特性、形态特征,以及温度、pH对菌丝体生长和孢子萌发的影响。经室内外药剂筛选试验,明确克霉灵、甲醛、硫酸铜和石灰水可有效杀灭该病菌。     

产酶溶杆菌OH11代谢产物HSAF对梨树腐烂病的防治效果

HSAF(heat stable antifungal factor)是产酶溶杆菌Lysobacter enzymogenes OH11中分离鉴定的一种小分子广谱抗真菌和卵菌物质,为进一步明确HSAF防治梨树腐烂病的潜力,分别采用生长速率测定法、显微镜观察法和刮治涂抹法测定了HSAF对梨树腐烂病菌的室内毒力以及对梨树腐烂病的田间防治效果。结果表明,HSAF对梨树腐烂病菌有较强的生长抑制作用,EC50值为0.5μg/m L;HSAF可导致梨树腐烂病菌菌丝体出现扭曲、近顶端处分枝和顶端肿胀等畸形现象;40μg/m L HSAF凝胶剂对梨树腐烂病的涂治愈合率可达81.3%,与2.12%腐植酸铜水剂的涂治愈合率(85.3%)无显著差异;对于分枝裂口或冻伤处、向阴、主杆或中心枝上的病疤,经40μg/m L HSAF凝胶剂涂抹后的愈合率高于2.12%腐植酸铜水剂。对于剪锯口处和向阳或分枝上的梨树腐烂病病疤,经2.12%腐植酸铜水剂涂抹后的愈合率高于40μg/m L HSAF凝胶剂;两种药剂对不同位置病疤的涂治效果不同,可作互补使用。本研究结果为梨树腐烂病的田间防治提供了一种新的生防制剂,同时也可望为其他果树腐烂病害的防治提供生防药剂资源。     

黑龙江省玉米茎基腐病病原菌研究初报

玉米茎基腐病乃世界性玉米病害,自70年代以来我国春、夏玉米产区均有不同程度发生为害。据各地调查,一般年份发病率10%—20%,严重地块可达50%以上。该病主要在玉米灌浆—成熟期发病,从而引起玉米植株的根部及茎基部腐烂、变软,叶片青枯,果穗下垂,导致植株早死,籽粒松瘪,产量严重下降,是我国目前玉米生产上急待研究解决的主要病害之一。作者自1988—1991年从全省各玉米主产区,采集了大量的病     

生物药剂防治苹果树腐烂病的田间试验

河南省自1987年开始在孟县、卢氏等县265亩苹果园中进行生物药剂治疗苹果树腐烂病的试验示范。以刮皮法和划刻法用农抗120、S-921和843康复剂涂抹病疤,一年后在发病季节调查。以刮皮法用农抗120处理的病疤,治愈率达100％,无一复发。以划刻法用农抗120处理的病疤治愈率为78-90％,以S-921和843康复剂处理的治疗效果达100％。作者认为这些生物药剂可取代福美砷治疗苹果树腐烂病。     

油茶炭疽病的发生与蔓延

四年来,作者对油茶炭疽病的侵染途径、传播方式、发病的阶段性、特点和具体条件职及病害蔓延等規律进行了研究。 結果指出,病菌侵染途径以伤口为主,也可能从自然孔道侵害果实。潛育期随气温上升而縮短,15℃至28℃时,潛育期由15天缩短为5天。分生孢子借助雨滴、风夹雨进行传播,干燥气流不能传菌。林間象(虫甲)、螞蚁不是传病的主要媒介。病害发生具有鮮明的季节性。果实发病期长,自4月至10月。病害有初期、中期、盛期和末期四个时期。感病宿主存在、菌源量积累和高温降雨为病害发生、发展的决定性因素。病害发展有間歇期和消长期。植株发病类型有:早发型、中发型、后发型及突发型四种。病果类型有:内侵型、邻侵型和外侵型三种。油茶炭疽病的逐年蔓延速度在一年内为36.5—50.0％;二年内为51.9—60.3％;三年内为55.8—61.8％。     

苹果树腐烂病的发病过程和药剂防治研究

本文分两部分。第一部分概述了陕西风县秦岭高地苹果树腐烂病的发生发展过程,指出腐烂病菌主要是先在树皮的落皮层内潜伏侵染,进而侵害健组织。第二部分为防治试验。根据腐烂病的发生发展过程,于6月下旬和11月中旬对主干和大枝下部涂40%福美砷可湿性粉剂50倍悬浮液二次,获得了施药部位新病减少90%,“病疤重犯”减少80%的防治效果。与在辽宁兴城的试验,防效近似。     

苹果干腐病发生与防治

根据1960—1961年的研究,苹果干腐病在辽宁省,每年从5月中旬到10月均能发生为害,6月分为发生发展的第一次高峯;8月下旬至9月上旬为第二次高峯。苹果干腐病的发生与气候条件有密切关系。干旱与积水均能诱发病害的发生,而干旱的影响最大。地势与发病亦有影响,低洼地发病较重。树势强弱与本病的发生有密切关系。栽培管理条件好,树势旺壮者,病势一般较轻。喷药保护树干有一定作用,彻底刮治病斑,再涂抹石灰硫磺合剂,效果很好。     

太阳辐射与苹果树腐烂病早春发病的关系以及树干保护的防腐作用

 苹果树腐烂病在早春有一次发病高峰,在此高峰期,主干、主枝上的原发病斑的分布具有明显的方位倾向。不同方位的树皮受日光照射后,皮温比气温高,其增温幅度愈大,增温持续时间愈长,则该方位上的发病点愈密集。因而认为腐烂病早春发病所表现的方位性与此期间树皮受日光照射后的增温有关。按风速1.1~3.8米/秒、低云量0~2级,12~14点阳光直射面树皮温度与气温间的关系可以直线回归式表之;t_{b (皮温)}=7.70+1.93t_{a (气温)}。河北省二、三月份由阳光辐射引起树皮增温的条件经常存在。采用秋后涂白保护树体的常发病部位可以降低早春树皮增温、减轻病害,推荐桐油皂白涂剂。     

The effect of Cryphonectria parasitica on water relations of American chestnut

Chestnut blight has commonly been regarded as a phloem disease due to conspicuous stem cankers that result from infection by the fungal pathogen Cryphonectria (Endothia) parasitica. Stomatal conductance (g_s), transpiration rate (E) and leaf water potential were measured throughout the day on leaves distal to naturally-occurring virulent (sunken bark with abundant stromata) or hypovirulent (swollen bark lacking stromata) cankers and cankers induced by inoculation with virulent or hypovirulent strains of C. parasitica. Relative to control stems, hydraulic conductivity (K_h), g_s and E were reduced significantly (α = 0·05) for both natural virulent cankers, and cankers that were induced by a virulent strain. These effects were less pronounced for both natural and induced hypovirulent cankers. Isolation experiments revealed that the percentage of xylem tissue chips yielding C. parasitica was greater for virulent than for hypovirulent cankers. The data provide evidence that the localized presence of C. parasitica in cankers of American chestnut results in stomatal closure, possibly as a direct result of xylem dysfunction.     

Pewenomyces kutranfy gen. nov. et sp. nov. causal agent of an important canker disease on Araucaria araucana in Chile

Araucaria araucana, (commonly referred to as araucaria, pewen, or monkey puzzle tree) is an ancient conifer endemic to the Chilean and Argentinian mountain ranges where it has a sacred relevance to indigenous communities. During 2015, a serious disease was noticed on trees of all ages in most of the natural distribution of this iconic tree. Four areas were surveyed, and the most important symptoms of the disease were cankers on branches and stems resulting in copious resin exudation. Trees were monitored for a period of two years and isolations were made from the cankers. Field observations showed that the disease typically begins on the leaves or at the leaf bases and progresses downwards to initiate cankers that can girdle branches or stems within a two-year period. Black ascomata, resembling those of Caliciopsis species previously described from A. araucana, were consistently found developing in the cankers from which isolations were made. Phylogenetic analyses of the ITS, nucSSU, and nucLSU gene regions showed that the fungus resides in the Coryneliaceae but is distinct from other genera in that family. The morphological characteristics and phylogenetic position of the fungus show that it represents a new genus and species, described here as Pewenomyces kutranfy gen. nov. et sp. nov. Pathogenicity trials on trees under field conditions confirmed that this newly described fungus is able to cause cankers on A. araucana similar to those found under natural conditions.     

杜鹃茎基腐病病原菌的鉴定

1992～1993年江苏省宜兴市的比利时杜鹃上发生了严重的茎基腐病,大量植株枯死。从植株和基质中获得的38个分离物中,14个为腐霉Pythium spp.,13个疫霉Phytophthoraspp.,7个拟盘多毛孢Pestalotiopsis spp.,3个青霉Penicillium spp.和1个刺盘孢Collectotrichum sp.。其中,只有腐霉和疫霉具有较强的致病力。作者对代表菌株RH-1和RH-3进行了种的鉴定。结果表明,昆明腐霉Py.kunmingense和柑橘褐腐疫霉Ph?citrophthora为杜鹃茎基腐病的致病菌。     

First report of the canker pathogen Endothia gyrosa on Eucalyptus in South Africa

During country-wide surveys of Eucalyptus plantations for Cryphonectria canker, cankers distinctly different from those usually associated with Cryphonectria cubensis were observed. These cankers were less severe and were exemplified by cracked and slightly swollen areas on the bark. Endothia gyrosa , a well-known pathogen of woody plants including Eucalyptus spp., was consistently associated with these cankers. The pathogen is easily distinguished from C. cubensis by the presence of orange-brown stromata and non-septate ascospores. Inoculations on Eucalyptus grandis resulted in lesions similar to those observed on naturally infected trees. The disease associated with E. gyrosa is widespread in South Africa, and research is required to establish control strategies.     

Thousand cankers disease in Europe: an overview

Walnut (Juglans regia L.) is traditionally present in most European countries as an ornamental tree, and in Southern Europe in particular it is grown for both fruit and wood. Since the 1980s, to supply the increasing demand for walnut timber, large areas of southern and central Europe, from France to Hungary, have been planted with black walnut (Juglans nigra L.) to provide wood for furniture production. The fungus Geosmithia morbida and its vector Pityophthorus juglandis, causing the thousand cankers disease of walnut in the USA in the last 2 decades, were recently reported in Europe (in Italy) on both walnut species. Thousand cankers disease can have a high negative impact on the landscape and economy of many agricultural and forest areas. Following a detailed pest risk analysis performed by EPPO in 2015, both organisms were included in the EPPO A2 List of pests recommended for regulation as quarantine pests. The main biological, epidemiological and monitoring aspects of thousand cankers disease and its status in Europe are reported.     

广州地区瓜类蔬菜疫病(死藤)发病条件及防治的初步调查研究

1976—78年,我们对广州地区瓜类蔬菜普遍出现的“死藤”病进行了初步调查研究。通过分离、培养及接种试验证明,病原菌是一种疫霉菌(Phytoph-thora sp.)。从调查结果来看,本病多在生长后期(结瓜期)发生,多雨高湿是决定本病发生流行的重要因素,而温度对加速和延缓病情的发展具有一定的作用。瓜类蔬菜连作以及由于地势低洼,过度密植和灌溉所造成的潮湿小气候都会加重本病的发生。在黄瓜品种间抗病性表现出一定的差异。试验证明,百菌清是防治本病的有效药剂,于发病前或发病初期每隔4～7天喷一次75%可湿性粉剂的600倍稀释液,连喷3～4次,可获得较好的效果。     

Pestalotiopsis canker of cypress in Israel

The occurrence of a new type of canker on stems and branches of cypress trees(Cupressus sempervirens L.) in Israel is reported.Pestalotiopsis funerea (Desm.) Steyaert was isolated from the cankers. Its pathogenicity was confirmed by formation of typical disease symptoms in inoculated plants and reisolation of that fungus from the cankers. Canker development was significantly enhanced when extreme water stress (water potential of -4.7 MPa) was imposed prior to inoculation.