玉米茎腐病菌毒素致病力初报

通过提取玉米茎腐病菌毒素粗提液,证实玉米茎腐病原菌(镰刀菌和腐霉菌为主)在镰刀菌毒素培养液、查氏培养液和普通培养液中,能产生和玉米小斑病菌毒素(简称HM毒素,下同)类似的致病毒素。该物质能抑制种子根的生长。接种在玉米叶片上能产生典型的萎蔫枯死斑;用上述3种培养液培养病原菌,产生的毒素致病力差异不显著;不同类型病原菌产生的毒素致病力和同一类型病原菌不同菌株产生的毒素致病力差异都极显著。玉米品系对茎腐病原菌产生的毒素抗病性差异也极显著。     

大豆毛口壳叶斑病菌产毒素的研究

 针对目前生产上新发现的大豆毛口壳叶斑病菌（Aristastoma sp.）产生的毒素进行了研究。该病菌的Czapek培养液经乙酸乙酯萃取可获得毒素粗提物。通过对该菌产毒条件的研究表明,pH 7的改良Richard培养液产生毒素生物活性最强,培养温度25℃、黑暗条件下持续振荡培养20 d最有利于该病菌毒素的产生。毒素活性测定表明,毒素对大豆叶片产生与病菌作用相同的褪绿症状,对种子胚根生长有抑制作用,对幼苗有致萎作用,说明毒素是大豆毛口壳叶斑病病菌侵染过程中的主要致病因子。     

枸杞炭疽病菌毒素的初步研究

枸杞炭疽病菌(Colletotrichum gloeosporioides Penz)可产生有致病力的外毒素,其毒素可引起枸杞叶片形成黑色坏死斑,类似于病原菌侵染形成的症状。Czapek-Dox培养液适于枸杞炭疽病菌的生长和产毒,其适宜温度为25～28℃,初始pH为6,通气条件促进其生长和产生毒素。试验结果表明该毒素为多聚糖类物质,毒素液对不同品种枸杞的致病作用存在明显差异,与品种对枸杞炭疽病的抗性有关。     

杨树角斑病病原菌分离及其培养特性研究

对杨树角斑病菌进行分离和鉴定,并研究不同培养条件对其培养特性的影响,以获得病原菌的纯培养并筛选出最佳培养条件,为杨树角斑病防治提供理论参考。分别采用组织和单孢分离法分离病原菌,根据子实体形态和病菌rDNA ITS序列对其进行鉴定。观察不同培养基、温度、光照、pH对病原菌生长的影响。结果表明,自然条件下,用杨树角斑病菌的分生孢子分离较病组织分离易成功。根据病菌的形态特征和rDNA ITS序列分析,将病菌鉴定为柳假尾孢[Pseudocercospora salicina(Ell.&Ev.)Deighton]。培养基、温度、光照、pH等因素影响病菌在培养基上的生长。燕麦培养基、pH6～7、25℃、黑暗条件是适合的培养条件。     

立枯丝核菌AG-1IA对水稻致病力及粗毒素活性的测定方法研究

水稻纹枯病是严重影响水稻生产的真菌病害,水稻相对病斑高度法作为评估立枯丝核菌AG-1 IA致病力的传统方法,需要将水稻培养至分蘖末期或抽穗期,再进行活体接种,耗时耗力,且试验条件不易控制。本研究以水稻相对病斑高度法(活体接种)为对照,利用水稻离体叶鞘法和离体叶片法测定了水稻纹枯病菌致病力和粗毒素活性,比较活体接种法与离体接种法的相关性。结果表明水稻离体叶片法、水稻离体叶鞘法和水稻相对病斑法测定致病力和粗毒素活性结果均呈显著正相关,水稻离体叶片法和离体叶鞘法测定结果能够准确反映立枯丝核菌AG-1 IA的致病力和粗毒素活性,离体评估方法操作方便,试验条件易于控制。因此,水稻离体叶片法、叶鞘法可以替代活体接种法作为测定立枯丝核菌AG-1 IA致病力和粗毒素活性的方法。水稻离体叶片法、叶鞘法与活体接种法结合起来可作为测定立枯丝核菌AG-1 IA毒素活性测定的新方法。本研究的结果还表明,水稻不同组织对水稻纹枯病菌毒素敏感性不同,水稻的叶鞘组织比叶片组织对纹枯病菌敏感。由于粗毒素的致病力与活体菌株接种的致病力存在显著差异,因此纹枯病菌毒素以外的致病因子,也是不容忽视的。在定量分析立枯丝核菌AG-1 IA与水稻的互作中,需要将不同水稻的组织进行区分,才能更加精准地了解互作机制。     

马铃薯晚疫病菌拮抗粘细菌YR–35的分离鉴定及其代谢产物稳定性

从乌拉山镇的农田土壤中分离获得致病疫霉的高效拮抗菌株YR-35,通过形态特征、生理生化特征以及16S rDNA序列分析将其鉴定为变绿色粘球菌Myxococcus virescens。菌株YR-35对马铃薯晚疫病致病菌菌丝生长抑制率高达96.67%。抗菌活性物质在30~80℃处理1 h后菌丝生长抑制率可达21.70%,高于80℃时活性逐渐下降,90℃处理后菌丝生长抑制率仍然可达15.38%。活性物质在pH 5.0~9.0条件下菌丝生长抑制率保持在25.27%以上,当pH5.0或pH9.0时,抗菌活性显著降低。活性物质不能被蛋白酶降解,不受紫外线、自然光照射的影响。对马铃薯离体叶片的生防效果检测表明,菌株YR-35的发酵无菌液处理组叶片相对病斑面积仅为0.57%,对照组的相对病斑面积高达87.72%。菌株YR-35的发酵无菌液可以有效抑制致病疫霉侵染马铃薯叶片。本研究首次发现变绿色粘球菌对致病疫霉有显著拮抗活性,为研发有效防治马铃薯晚疫病的生物农药奠定了基础。     

短穗鱼尾葵灰斑病菌的鉴定及生物学特性*

［目的］ 明确引起短穗鱼尾葵灰斑病的病原菌及该菌的生物学特性。［方法］ 从短穗鱼尾葵感病组织上分离、纯化病菌,经致病性测定后根据其形态特征进行种类鉴定,并测定其在不同培养条件下的生物学特性。［结果］ 引起短穗鱼尾葵灰斑病的病原菌为小孢拟盘多毛孢菌［Pestalotiopsis microspora (Speg.) Satista &; Peresapud Batista］。该菌在PSA 培养基上长势最好;菌丝生长和孢子萌发的最适温度为25 ℃;完全光照条件最利于菌丝的生长和产孢;在pH5时菌丝生长最好,pH6时孢子萌发率最高,pH2时孢子不萌发;孢子的致死温度为50 ℃。［结论］ 上述结果可以为短穗鱼尾葵灰斑病的防治提供依据。     

温度对梨树腐烂病菌生长、病斑扩展及产毒素水平的影响

为探明温度对梨树腐烂病菌生长、病斑扩展及产毒素水平的影响,采用常规生物学方法和高效液相色谱法,测定了该病菌强致病力菌株LXS240101在不同温度下的菌丝生长、病斑扩展及产毒素水平。结果表明:菌株LXS240101最适宜的生长温度为25~30℃;在5~35℃范围内,梨树离体枝条接种梨树腐烂病菌后均能发病并导致病斑扩展,25℃时病斑扩展速度最快,面积达4.45cm2,5℃和35℃时病斑扩展速度缓慢,面积不足0.3 cm2。该菌株在梨树树皮培养基中最适宜的产毒素温度为20℃,10~25℃条件下可产生5种毒素,而在其它温度下仅产生3~4种;接种该菌株的梨树离体枝条5℃条件下未检测到间苯三酚和对羟基苯甲酸,且毒素总量最低,其余温度下均可检测到5种毒素,最适宜的产毒素温度为10℃,毒素总量可达224.14μg/g干组织。     

豇豆轮纹病综合防治技术

正豇豆轮纹病又称灰斑病、棒孢叶斑病,是豇豆的一种常见病害。近年该病在豇豆上的为害呈上升态势,多在开花结荚后发病,主要为害叶片,也为害茎和豆荚,影响豇豆产量。1发病症状1.1叶片症状初期出现红褐色小斑点,微突起,扩大后,病斑圆形或近圆形,直径4~8 mm,红褐色,边缘明显,斑面上有明显的同心轮纹,病部中心轮纹颜色稍深,病部组织不产生黑色小粒点。后期病斑连片,叶片发黄枯死。叶脉发病,呈褐色坏死斑。天气     

粗皮侧耳生物学特性及其与杀线虫毒力的关系

 本文报道粗皮侧耳(Pleurotus ostreatus)的生物学特性,尤其是生物学特性与杀线虫毒力的关系。该菌的野生型、驯化型、单孢分离株及孢子分离株的菌丝均能迅速杀死线虫。在固体培养条件下,成熟菌丝产生丰富的毒素球,幼嫩菌丝不产生毒素球;该菌在多种固体培养基,甚至营养缺乏的水琼脂上也生长良好;生长的最适条件为24~28℃、pH5.6~8.0、固体或液体遮光培养。尽管营养、温度、pH及光照等对菌丝生长均有显著影响,但并不影响其对线虫的毒力,各菌株间毒力无差异,线虫与菌丝接触48h,死亡率均达90%以上;液体培养滤液能杀死线虫,但其对线虫毒力的强弱却与菌株、滤液浓度及培养时间等有关。首次以实验证明了该菌在液体培养条件下可产生杀线虫毒素。     

Dermestid beetles in ‘evolution Canyon’, lower Nahal Oren, Mt. Carmel, including new records for Israel

Fifteen species of dermestid beetles were recorded at ‘Evolution Canyon’ (EC), Lower Nahal Oren, Mt. Carmel, Israel. They represent ~35% of known Israeli dermestid species. The following three species were recorded for the first time in Israel:Trogoderma svriaca Dalla Torre, 1911;Ctesias svriaca Ganglbauer, 1904; andAnthrenus (s.str.) jordaniens Pic, 1934. Adults of 13 species were collected on the more solar radiated, warmer and climatically more fluctuating south-facing slope (SFS); ten species were collected on the opposite, north-facing slope (NFS), which was cooler and climatically more stable. The abundance of adult dermestid beetles was 1.9 times higher on the SFS than on the NFS (86 and 47, respectively). Species richness and abundance distribution at EC (three collecting stations on each slope and one at the valley bottom) were significantly negatively correlated with the plant cover that consisted of trees and bushes (Spearmanr _s ,P=0.007 and 0.039, respectively) and perennials (Spearmanr _s ,P=0.039 and 0.077, respectively), indicating that non-woody plants were preferred by adult dermestid beetles.     

Epidemiology of Toxigenic Fungi and their Associated Mycotoxins for Some Mediterranean Crops

Recent data on the epidemiology of the common mycotoxigenic species of Fusarium, Alternaria, Aspergillus and Penicillium in infected or colonized plants, and in stored or processed plant products from the Mediterranean area are reviewed. Emphasis is placed on the toxigenicity of the causal fungal species and the natural occurrence of well known mycotoxins (aflatoxins, ochratoxins, fumonisins, trichothecenes, zearalenone, patulin, Alternaria-toxins and moniliformin), as well as some more recently described compounds (fusaproliferin, beauvericin) whose toxigenic potential is not yet well understood. Several Fusarium species reported from throughout the Mediterranean area are responsible of the formation of mycotoxins in infected plants and in plant products, including: Fusarium graminearum, F. culmorum, F. cerealis, F. avenaceum, F. sporotrichioides and F. poae, which produce deoxynivalenol, nivalenol, fusarenone, zearalenone, moniliformin, and T-2 toxin derivatives in wheat and other small grains affected by head blight or scab, and in maize affected by red ear rot. Moreover, strains of F. verticillioides, F. proliferatum, and F. subglutinans, that form fumonisins, beauvericin, fusaproliferin, and moniliformin, are commonly associated with maize affected by ear rot. Fumonisins, were also associated with Fusarium crown and root rot of asparagus and Fusarium endosepsis of figs, caused primarily by F. proliferatum. Toxigenic A. alternata strains and associated tenuazonic acid and alternariols were commonly found in black mould of tomato, black rot of olive and citrus, black point of small cereals, and black mould of several vegetables. Toxigenic strains of A. carbonarius and ochratoxin A were often found associated with black rot of grapes, whereas toxigenic strains of A. flavus and/or P. verrucosum, forming aflatoxins and ochratoxin A, respectively, were found in moulded plant products from small cereals, peanuts, figs, pea, oilseed rape, sunflower seeds, sesame seeds, pistachios, and almonds. Finally, toxigenic strains of P. expansum and patulin were frequently found in apple, pear and other fresh fruits affected by blue mould rot, as well as in derived juices and jams.     

A survey of the genera of<Emphasis Type="Italic">Microgaster</Emphasis> latreille and<Emphasis Type="Italic">Hygroplitis</Emphasis> thomson (Hymenoptera: Braconidae: Microgastrinae) from China

The genera ofMicrogaster Latreille 1804 andHygroplitis Thomson 1895 from China are presented systematically in this paper. Thirty-two species ofMicrogaster and three species ofHygroplitis are known in China. Diagnosis, character variation, distribution and host of each species among the two genera are presented, including its host and distribution. Keys to the species ofMicrogaster andHygroplitis are given. http://www.phytoparasitica.org posting Dec. 19, 2006.     

Plant Viruses Transmitted by Whiteflies

One-hundred and fourteen virus species are transmitted by whiteflies (family Aleyrodidae). Bemisia tabaci transmits 111 of these species while Trialeurodes vaporariorum and T. abutilonia transmit three species each. B. tabaci and T. vaporariorum are present in the European–Mediterranean region, though the former is restricted in its distribution. Of the whitefly-transmitted virus species, 90% belong to the Begomovirus genus, 6% to the Crinivirus genus and the remaining 4% are in the Closterovirus, Ipomovirus or Carlavirus genera. Other named, whitefly-transmitted viruses that have not yet been ranked as species are also documented. The names, abbreviations and synonyms of the whitefly-transmitted viruses are presented in tabulated form together with details of their whitefly vectors, natural hosts and distribution. Entries are also annotated with references. Whitefly-transmitted viruses affecting plants in the European–Mediterranean region have been highlighted in the text.     

Broad bean mottle virus in Morocco; curculionid vectors,and natural occurrence in food legumes other than faba bean (Vicia faba)

Broad bean mottle virus (BBMV) was transmitted from infected to healthy faba-bean plants by the curculionid weevilsApion radiolus Kirby,Hypera variabilis Herbst,Pachytychius strumarius Gyll,Smicronyx cyaneus Gyll, andSitona lineatus L. The latter appeared to be an efficient vector: acquisition and inoculation occurred at the first bite, the rate of transmission was c. 41%, and virus retention lasted for at least seven days.S. lineatus transmitted the virus from faba bean to lentil and pea, but not to the three genotypes of chickpea tested. This is the first report on the generaHypera, Pachytychius, andSmicronyx as virus vectors, and onA. radiolus, H. variabilis, P. strumarius, andS. cyaneus as vectors of BBMV.Out of 351 samples of food legumes with symptoms suggestive of virus infection, 16, 11, 19, and 17% of the samples of chickpea, lentil, pea, and common bean, respectively, were found infected when tested for BBMV in DAS-ELISA. This is the first report on the natural occurrence of BBMV in chickpea, lentil, pea, and common bean. The virus should be regarded as a food-legume virus rather than a faba-bean virus solely, and is considered an actual threat to food legume improvement programmes.     

Characterization of potato potyvirus Y (PVY) isolates from seed potato batches. Situation of the NTN, Wilga and Z isolates

A collection of 38 PVY isolates from seed potato batches, originating from several Western European countries, was characterized by using current biological, serological and molecular tools differentiating PVY strains and groups. The correlation between the three kinds of tests was good but not absolute. No single serological or PCR method was able to discriminate among the five isolate groups found. Twenty-nine isolates belonged to the PVY^N strain and six to the PVY^O strain. No PVY^C was found. Two other isolates reacted serologically like PVY^O, but were unable to elicit a hypersensitive response from the Ny_tbr gene and probably represent the PVY^Z group. At the molecular level, these two isolates showed a combination of both PVY^O and PVY^N and could be recombinants of these strains. Another isolate reacted serologically like PVY^O, but induced vein necrosis in tobacco, like PVY^N-Wilga. Some PVY^N isolates caused tuber ring necrosis in glasshouse conditions. These might belong to the PVY^NTN group. The PVY^NTN, PVY^N-Wilga and PVY^Z groups probably represent pathotypes within strains PVY^N and PVY^O, respectively. The present study also confirms previous reports showing a high genetic variation at the 5 end within the PVYN strain.     

The autumn leafroller: Phenology,damage and parasitoids in a Dutch apple orchard

The phenology of the autumn leafroller,Syndemis musculana, a local pest of apple, was studied in order to forecast larval emergence. From 1983–1986, peak flight as determined with sexpheromone traps was always between 13–18 May. The duration of embryonic development was determined at various constant temperatures and used to estimate the periods of egg hatch in these four years. Each year, most eggs should have hatched in the second decade of June.Differences in attack rates between apple cultivars seem to be explained largely by the variation in picking time. Larvae are only half grown at the beginning of harvest (cv. James Grieve), and have gone into hibernation when the latest variety (cv. Golden Delicious) is picked. Moreover, the varieties Cox's Orange Pippin and Belle de Boskoop, picked about half time, are liable to receive additional damage by caterpillars brought with the picked fruits into storage.Various hymenopterous parasites were reared from caterpillars. As the only leafroller in the orchard which hibernates as mature larva,S. musculana may promote winter survival of some parasitoids, like the eulophidColpyclypeus florus.Samenvatting De fenologie van de herfstbladroller (Syndemis musculana Hübner), een incidentele plaag op appel, werd nader bepaald met het doel het uitkomen van de eieren te kunnen voorspellen. In 1983–1986 viel de piekvlucht, bepaald met behulp van feromoonvallen, steeds tussen 13 en 18 mei.De ontwikkelingsduur van de eieren bij verschillende constante temperaturen werd gebruikt om de periode van uitkomen te schatten. De meeste eieren zullen ieder jaar in de eerste helft van juni uitkomen.Geconstateerde verschillen in schade tussen appelrassen blijken goeddeels terug te voeren op verschillen in pluktijdstip. De rupsen van de herfstbladroller zijn pas half-was als de eerste appels eind augustus geplukt worden, terwijl tegen het einde van de oogst begin oktober de meeste al in winterslaap zijn. Met name tussentijdse rassen, als Cox's Orange Pippin and Schone van Boskoop, lopen extra schade op doordat grotere rupsen met de geplukte vruchten in de kist terecht komen.Uit de rupsen werden negen, al van andere boomgaardbladrollers bekende, sluipwespen gekweekt, Omdat deze bladrollersoort, als enige in de boomgaard, als volgroeide rups overwintert, lijkt zij bij uitstek geschikt als winterwaard.This study was carried out at the Experimental Orchard De Schuilenburg, Schuilenburg 3, 4041 BK Kesteren, the Netherlands, to which address correspondence should be addressed.     

Characterization of Sclerotinia minor populations in Texas peanut fields

In the summer of 2004 an epidemic of sclerotinia blight of peanut, a disease caused by Sclerotinia minor, occurred in Texas in fields where the disease was never previously detected. The disease was observed on many plants within one of the fields (>3000 disease foci), although most foci were <1 m. It is hypothesized that these observations were inconsistent with the recent introduction of a monocyclic pathogen, even if disease developed under conducive environmental conditions. The pattern of disease is most suggestive of the presence of foliar (ascospore) infections, although air temperature was above the known limits for apothecia development if the pathogen had arrived in the field in 2004 peanut seed. To further examine this epidemic, 232 isolates were collected, across a variety of spatial scales spanning this field and other Texas peanut fields, and evaluated for aggressiveness, fungicide sensitivity and genotypic diversity. There was wide variation among isolates for the phenotypic characteristics measured, but there was no evidence that a genotypically unique, highly aggressive, and fungicide resistant isolate had been introduced or evolved. The predominant genotype, TX1, which contained 154 isolates, was found in every county and field population.     

Eyespot of Cereals Revisited: ITS phylogeny Reveals New Species Relationships

Four species so far classified in Pseudocercosporella or Ramulispora (hyphomycetes) are associated with eyespot disease symptoms of cereals. Two of these have been linked to teleomorphs that were described in Tapesia. Sequence data derived from the Internal Transcribed Spacer region (ITS1, 5.8S and ITS2) of the rDNA operon showed, however, that the eyespot fungi associated with Tapesia are not congeneric with Ramulispora sorghi, the type of Ramulispora. The genus name Tapesia is now rejected in favour of the conserved name Mollisia, which appears to comprise heterogeneous fungi. Tapesia yallundae is not closely related to the type of Mollisia, M. cinerea, but clusters separately, being more closely allied to species with Cadophora anamorphs. A new holomorph genus, Oculimacula, is therefore proposed for teleomorphs of the eyespot fungi, while the anamorphs are accommodated in Helgardia gen. nov.     

Tumours of Begonia and some other ornamentals,induced by Corynebacterium fascians

In 1975 many tumours were observed in plants ofBegonia Schwabenland grown in Aalsmeer. Submersion of the roots ofNicotiana megalosiphon seedlings in a homogenate of tumorous tissue, induced tumours after two weeks. Short periods of submergence yielded results similar to those obtained after longer periods. Tumour homogenates lost their infectivity after ten min at 50°C. Aphids transmitted the infectious agent.Treatment with propylene oxide did not inhibit infectivity completely. Filtration through a 450 nm filter removed the infectious agent.Tobacco tumor virus or a viroid could not be isolated. Cultures ofCorynebacterium fascians, isolated from tumours ofN. megalosiphon were highly infectious and induced tumours in healthyN. megalosiphon andBegonia. Tumorous tissue homogenates ofPelargonium zonale, Dahlia sp.,Gladiolus sp., andLilium sp. also caused tumours inN. megalosiphon, from whichC. fascians was isolated. It was not possible to produce tumours inN. megalosiphon with homogenates from roses with symptoms of bud proliferation.Samenvatting In 1975 werden vele tumoren waargenomen inBegonia Schwabenland op Aalsmeerse bedrijven (Fig. 1). De infectiositeit van tumorweefsel kon goed en snel worden vastgesteld door de wortels van zaailingen vanNicotiana megalosiphon in een homogenaat van tumorweefsel te dompelen. Tumoren ontstonden na twee weken, de eindbeoordeling geschiedde na een maand (Fig. 2). Ook verschillende andereNicotiana spp.,Melilotus officinalis (Fig. 3) enPisum odoratum (Fig. 4) werden aangetast.Bij de infectiositeitstoets gaven zeer korte dompeltijden even goede resultaten als langere (Tabel 1). Infectieus sap verloor zijn infectievermogen na 10 min verhitting bij 50°C. Bladluizen brachten de smetstof over. Propyleenoxide verminderde de infectiositeit wel, doch onderdrukte deze niet totaal. Bij filtratie door een 450 nm filter bleef het infectieuse agens op het filter achter. Het tumor-inducerende agens was ook aanwezig in die delen van planten met tumoren welke gezond leken en het ging voor een gering deel over met zaad (Tabel 2).Uit tumoren konden wij geen tabakstumorvirus of een viroïde isoleren. Culturen vanCorynebacterium fascians, geïsoleerd uit tumoren vanN. megalosiphon bleken zeer infectieus en veroorzaakten tumoren inN. megalosiphon enBegonia. Homogenaten van tumorweefsel vanPelargonium zonale, dahlia (Fig. 5), gladiool (Fig. 6) enLilium Mid Century Hybrid Enchantment (Fig. 7) veroorzaakten ook tumoren opN. megalosiphon, waaruitC. fascians werd geïsoleerd. Met sap van kroeskopzieke rozen konden wijN. megalosiphon niet besmetten.