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1.
小麦赤霉病是小麦穗期的主要病害之一。化学防控一直是小麦主产区防控赤霉病的主要措施。为明确几种新型杀菌剂对小麦赤霉病的防效和对小麦籽粒DON毒素含量的影响,于2018年进行了氰基丙烯酸酯类和三唑类杀菌剂单剂及其复配剂对赤霉病的防效试验。结果表明:30%戊唑·多菌灵悬浮剂(SC)1500 mL/hm^2处理对赤霉病病穗防效达92.40%,病指防效达93.20%,小麦籽粒DON毒素检出量较不用药对照降低80.38%;25%氰烯菌酯SC 2000 mL/hm^2处理对赤霉病的病穗防效达86.80%,病指防效达88.78%,小麦籽粒DON毒素检出量较不用药对照降低88.19%;48%氰烯·戊唑醇SC 900 mL/hm^2和40%丙硫·戊唑醇SC 600 mL/hm^2对小麦赤霉病的病穗防效分别为77.20%、78.00%,病指防效分别为80.27%和79.59%,对籽粒DON毒素检出量较不用药对照分别降低73.87%和81.42%。在小麦赤霉病较重发生的情况下,上述4种杀菌剂单剂或复配剂1次用药既能高效控制病情,又能有效控制小麦籽粒DON毒素不超标。本试验研究进一步阐明,氰烯菌酯、戊唑醇、丙硫菌唑等杀菌剂及其复配剂均能有效控制小麦赤霉病的危害,并能有效降低小麦籽粒DON毒素含量;吡唑醚菌酯单剂及其复配剂虽然对小麦赤霉病的病穗和病指防效也较高,但控制小麦籽粒DON毒素含量效果相对较差。研究结果为小麦穗期赤霉病化学防控提供了科学参考。  相似文献   

2.
2016年研究了3种复配杀菌剂对小麦赤霉病的田间防治效果。结果表明,以有效成分用量35%丙环唑·多菌灵悬乳剂630~840 g/hm~2处理的田间防效85.28%~88.83%,30%多菌灵·戊唑醇悬浮剂180~225 g/hm~2处理田间防效86.74%~92.36%,30%多菌灵·氟环唑悬浮剂450~540 g/hm~2处理田间防效85.61%~90.28%,3种复配剂对小麦赤霉病的田间防治效果均优于相应单剂,且显著高于常规杀菌剂多菌灵。  相似文献   

3.
不同配比多菌灵与戊唑醇防治小麦赤霉病研究   总被引：3，自引：0，他引：3  
在感病品种和中等肥力土壤条件下,分析多茵灵、戊唑醇不同比例混配对小麦赤霉病的室内活性和田间防效以及对小麦产量及DON毒素的影响。结果表明:多菌灵、戊唑醇2:1~7:1比例混配对小麦赤霉病菌均呈加和作用,多菌灵与戊唑醇4:1、5:1、7:1对小麦赤霉病的田间防效在60.3%~73.3%之间,小麦产量增加49.1%~72.2%,多菌灵:戊唑醇7:1比例混配在用药量较少的情况下防效与其他比例混配药剂防效相当,但3种配比处理间小麦产量和DON毒素并无显著差异(P0.05)。结合生产实际,48%戊·多悬浮剂、80%戊·多可湿性粉剂、40%戊·多悬浮剂在其中高剂量下在小麦扬花10%、小麦扬花100%时期各施用1次对小麦赤霉病有理想防效,具有推广意义。  相似文献   

4.
小麦赤霉病在河南唐河呈逐年加重趋势,严重影响小麦生产,并对当地常规防治药剂产生了抗性。为了筛选出防治该病效果较好的替代药剂,以常规药剂多菌灵单剂为对照,选择了4种新型复配制剂对当地小麦赤霉病进行田间防效试验。结果发现,在两次施药后,30%戊唑醇·福美双悬浮剂90 mL/667m^2、48%氰烯菌酯·戊唑醇悬浮剂50 mL/667m^2、20%氰烯菌酯·己唑醇悬浮剂100 mL/667m^2、45%戊唑醇·咪鲜胺可湿性粉剂35 g/667m^2 4个处理对小麦赤霉病的病指防效均在70%以上,显著高于对照药剂。其中,以48%氰烯菌酯·戊唑醇悬浮剂处理的防效最高,达80.2%;4个复配剂处理区的小麦较清水对照区增产率也均在30%以上,增产效果也明显优于多菌灵。  相似文献   

5.
为探明不同杀菌剂对小麦赤霉病和小麦籽粒DON毒素(包括DON、3-ADON和15-ADON)的控制效果, 采用菌丝生长速率法测定了12种药剂对禾谷镰刀菌野生型菌株PH-1的室内活性, 同时采用液相色谱-串联质谱法(LC-MS)测定了这些药剂对DON毒素的抑制效果, 并开展了小麦赤霉病及籽粒DON毒素的田间防治试验。结果表明, 12种原药对菌丝生长抑制活性强弱依次为氟唑菌酰羟胺>咪鲜胺>戊唑醇>丙硫菌唑>叶菌唑>氰烯菌酯>氟环唑>多菌灵>甲基硫菌灵>吡唑醚菌酯>嘧菌酯>井冈霉素A。氟环唑EC50和EC90离体胁迫均刺激DON毒素产生, 其他杀菌剂EC50和EC90胁迫均抑制DON毒素产生。田间试验结果表明, 200 g/L氟唑菌酰羟胺SC、30%丙硫菌唑OD和20%叶菌唑WP病指防效和DON防效为87.68%~94.77%; 430 g/L戊唑醇SC、25%氰烯菌酯SC、45%咪鲜胺EW、25%氟环唑SC、50%多菌灵WP和70%甲基硫菌灵WP病指防效和DON防效为57.63%%~85.49%; 250 g/L吡唑醚菌酯EC和250 g/L嘧菌酯SC病指防效分别为72.18%和51.98%, DON防效分别为43.06%和-7.96%; 24%井冈霉素A AS病指防效和DON防效分别为42.37%和62.87%。药剂离体和田间控毒效果不完全一致, 赤霉病有效防控是DON防控的前提, 病害防效与DON防效不完全一致, 本研究为小麦赤霉病及籽粒DON毒素防控提供了科学依据。  相似文献   

6.
江苏小麦赤霉病综合防控关键技术研究   总被引：5，自引：0，他引：5  
近年来气候变暖、秸秆还田和赤霉病菌对多菌灵的抗性上升使江苏省小麦赤霉病流行频率提高。本研究通过田间小区试验,对小麦赤霉病的综合防控关键技术进行了比较。试验结果表明,目前赤霉病菌对多菌灵抗药性频率已达60%以上,多菌灵的防效明显下降,低于60%。研究明确了赤霉病的防控适期和防治次数,对淮南、淮北主要小麦品种进行赤霉病自然发病鉴定,并阐述了品种抗性和药剂防治间的互作效应。研究结果揭示,选育推广对小麦赤霉病具有抗性的品种是小麦赤霉病防控的基础,把握适期于小麦扬花期施用非多菌灵类的戊唑醇、氰烯菌酯、丙硫菌唑等其他杀菌剂可有效控制病害的发生。  相似文献   

7.
为明确不同杀菌剂防治小麦赤霉病和减少小麦籽粒中DON(脱氧雪腐镰刀菌烯醇)毒素积累的效果,于大田人工接菌条件下进行了不同杀菌剂对小麦赤霉病的防治试验,并于收获期测定了不同药剂处理的小麦籽粒中DON毒素含量。结果表明:两种处理方式下,50%多菌灵WP,30%多·酮SC,25%戊唑醇WP,25%氰烯菌酯SC和70%甲基硫菌灵WP处理中,除先喷药后接菌条件下25%戊唑醇WP在病粒率和籽粒中DON积累上没有显著防治效果,接菌后1d喷药条件下50%多菌灵WP、25%戊唑醇WP在病粒率上没有显著防治效果;30%多·酮SC在病粒率和籽粒中DON积累上没有显著防治效果外,各处理对小麦的病穗率、病情指数、病粒率和籽粒中DON积累都有显著的防治效果(P0.05)。各处理的病穗率防效在42.4%~83.5%,病情指数防效在44.9%~88.2%,病粒率防效在34.7%~69.4%,籽粒中DON防效在48.0%~86.9%。上述几种杀菌剂具有明显的保护作用,其在先喷药后接菌条件下的防治效果均明显优于接菌后1d喷药的防治效果。两种处理方式下,30%己唑醇悬浮剂、25%嘧菌酯悬浮剂和12.5%烯唑醇可湿性粉剂处理在病穗率、病情指数、病粒率和籽粒中DON积累与清水对照处理没有显著性差异(P0.05)。  相似文献   

8.
采用菌丝生长速率法测定了叶菌唑分别与咪鲜胺、戊唑醇、丙硫菌唑和氟啶胺的几种不同配比复配剂对禾谷镰孢菌的室内联合毒力,并通过田间试验评价复配剂对小麦赤霉病的防效。结果表明,叶菌唑、咪鲜胺、戊唑醇、丙硫菌唑和氟啶胺对禾谷镰孢菌的有效抑制中浓度(EC_(50))分别为0.016 3～0.038 3、0.014 7、0.280 7、0.094 5、0.230 0μg/mL,复配剂叶菌唑∶咪鲜胺1∶2和叶菌唑∶戊唑醇1∶1具有增效作用,SR值分别为1.540 5和1.515 3。按此比例制备了30%叶菌唑·咪鲜胺水乳剂和20%叶菌唑·戊唑醇悬浮剂用以进行田间防效试验,结果显示,这2个复配剂的田间防效均与用量呈正相关性,且一次防效均在65%以上,并且对小麦安全,这一结果表明叶菌唑与咪鲜胺、戊唑醇这2种不同作用机制的杀菌剂可以复配使用,大大延缓了小麦赤霉病菌抗药性的进一步加剧,为赤霉病的综合防控和抗药性治理提供依据,具有良好的市场开发前景。  相似文献   

9.
近年来的调查结果表明,江苏垦区小麦赤霉病菌群体中抗多菌灵菌株的频率逐年上升,多菌灵防效逐年下降,部分农场采用多菌灵防治几乎失效。为了筛选替代多菌灵的药剂,我们在白马湖等6个农场对几种新杀菌剂进行了田间药效试验。结果表明,25%氰烯菌酯SC、40%叶菌唑SC和25%丙硫菌唑WP在所有农场都有较好的防治效果,其中25%丙硫菌唑WP对小麦赤霉病的防治效果最好,在所有农场其防效都超过80%,防治后乳熟期和成熟期病穗率变化不大。40%叶菌唑SC、25%丙硫菌唑WP以及25%氰烯菌酯SC和43%戊唑醇SC混用有显著增产作用,并能大幅度降低籽粒中DON含量。作者认为赤霉病的防治应立足种植抗(耐)病品种,扬花期选用有效杀菌剂适期进行防治。氰烯菌酯、叶菌唑和丙硫菌唑可作为多菌灵的替代药剂。  相似文献   

10.
多种杀菌剂对小麦赤霉病及其DON毒素的防效   总被引：1，自引：0，他引：1  
通过田间试验与室内检测,研究不同杀菌剂对小麦赤霉病的防治效果、对DON(脱氧雪腐镰刀菌烯醇)毒素的控制效果以及对小麦产量的影响。结果表明,200 g/L氟唑菌酰羟胺悬浮剂180 g/hm~2、48%丙硫菌唑悬浮剂288 g/hm~2和40%丙硫·戊唑醇悬浮剂240 g/hm~2对小麦赤霉病的防效较高,药后25d病指防效均达到90%以上。药剂处理有一定增产效果,相比对照区,各处理区产量增幅16.39%~31.91%,千粒重增幅29.69%~36.17%。各处理对小麦病粒率和籽粒中的DON毒素也有一定控制效果。200g/L氟唑菌酰羟胺悬浮剂180g/hm~2和40%丙硫·戊唑醇悬浮剂240 g/hm~2控制病粒率的效果最好,对应处理的病粒率分别为0.31%和0.32%。200 g/L氟唑菌酰羟胺悬浮剂180 g/hm~2和48%丙硫菌唑悬浮剂288 g/hm~2控制DON毒素的效果最好,对应处理的DON毒素检出量分别为197.33μg/kg和197.07μg/kg。  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
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.  相似文献   

14.
Plant Viruses Transmitted by Whiteflies   总被引：18，自引：0，他引：18  
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.  相似文献   

15.
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.  相似文献   

16.
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 PVYN strain and six to the PVYO strain. No PVYC was found. Two other isolates reacted serologically like PVYO, but were unable to elicit a hypersensitive response from the Nytbr gene and probably represent the PVYZ group. At the molecular level, these two isolates showed a combination of both PVYO and PVYN and could be recombinants of these strains. Another isolate reacted serologically like PVYO, but induced vein necrosis in tobacco, like PVYN-Wilga. Some PVYN isolates caused tuber ring necrosis in glasshouse conditions. These might belong to the PVYNTN group. The PVYNTN, PVYN-Wilga and PVYZ groups probably represent pathotypes within strains PVYN and PVYO, respectively. The present study also confirms previous reports showing a high genetic variation at the 5 end within the PVYN strain.  相似文献   

17.
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.  相似文献   

18.
Molecular diagnostic techniques have been developed to differentiate the Ascochyta pathogens that infect cool season food and feed legumes, as well as to improve the sensitivity of detecting latent infection in plant tissues. A seed sampling technique was developed to detect a 1% level of infection by Ascochyta rabiei in commercial chickpea seed. The Ascochyta pathogens were shown to be genetically diverse in countries where the pathogen and host have coexisted for a long time. However, where the pathogen was recently introduced, such as A. rabiei to Australia, the level of diversity remained relatively low, even as the pathogen spread to all chickpea-growing areas. Pathogenic variability of A. rabiei and Ascochyta pinodes pathogens in chickpea and field pea respectively, appears to be quantitative, where measures of disease severity were based on aggressiveness (quantitative level of infection) rather than on true qualitative virulence. In contrast, qualitative differences in pathogenicity in lentil and faba bean genotypes indicated the existence of pathotypes of Ascochyta lentis and Ascochyta fabae. Therefore, reports of pathotype discrimination based on quantitative differences in pathogenicity in a set of specific genotypes is questionable for several of the ascochyta-legume pathosystems such as A. rabiei and A. pinodes. This is not surprising since host resistance to these pathogens has been reported to be mainly quantitative, making it difficult for the pathogen to overcome specific resistance genes and form pathotypes. For robust pathogenicity assessment, there needs to be consistency in selection of differential host genotypes, screening conditions and disease evaluation techniques for each of the Ascochyta sp. in legume-growing countries throughout the world. Nevertheless, knowledge of pathotype diversity and aggressiveness within populations is important in the selection of resistant genotypes.  相似文献   

19.
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.  相似文献   

20.
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.  相似文献   

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