bluuebunny/crossref_metadata_2025 huggingface dataset:
Management of fungicide resistance in practice1
Authors: URECH P. A.
Published: April 2008

Successful management of fungicide resistance includes many more aspects than just the design of an effective anti‐resistance strategy. It involves all social groups engaged in plant disease control including industry, academia, extension and advisory services and, last but not least, the farmer. Various tasks must be carried out by these groups, and all must accept their share of responsibility. Only a comprehensive view of resistance management can help to prolong the useful life of the highly active new fungicides.
Certification des arbres fruitiers1
Authors: BERNHARD R.
Published: April 2008

L'auteur examine le développement de la certification virologique des arbres fruitiers en France ainsi que les principes de base adoptés. Les systèmes de certification des arbres fruitiers utilisés dans plusieurs pays européens sont comparés et les principales difficultés pouvant etre rencontrées sont discutées. Enfin, l'auteur propose diverses mesures afin de s'assurer: (1) que la certification n'entraine pas une limitation du nombre de cultivars disponibles; (2) que l'on arrive à un consensus sur les définitions des termes ‘virus‐free’et ‘virus‐tested’; (3) qu'il y ait un accord sur le nombre maximal d'étapes de multiplication entre le matériel initial indexe et le produit certifié. Des propositions sur l'harmonisation de la nomenclature sont également faites.
Patasson nitens, parasite spécifique de Gonipterus scutellatus en France1
Authors: PINET C.
Published: April 2008

Après un début de colonisation rapide et brutale des eucalyptus francais par Gonipterus scutellatus, principalement Eucalyptus globulus sur le littoral de la Cote d'Azur, il semble aujourd'hui qu'un fort ralentissement, voire meme un arret, soit intervenu dans la progression du charancon. Suite à une série de lachers du parasite spécifique Patasson nitens et à sa dissémination naturelle, sa distribution coincide maintenant pratiquement avec celle du ravageur et l'équilibre favorable ainsi créé mérite d'etre mieux défini afin de le maintenir.
Phoracantha semipunctata dans le Sud‐Ouest espagnol: lutte et dégâts1
Authors: TIRADO L. GONZALEZ
Published: April 2008

En 1982 et 1983, des campagnes massives d'installation d'arbres‐pièges (abattus) contre Phoracantha semipunctata ont été menées dans les provinces espagnoles de Huelva et de Sevilla. L'article décrit les procédures suivies et évalue les résultats, jugés positifs et prometteurs. Il est également fait état des dommages causés par P. semipunctata en 1983 dans la province de Huelva.
Les agents pathogènes d'origine tellurique; moyens d'intervention et biocénose1
Authors: TRAMIER R.
Published: April 2008

L'importance des agents pathogènes d'origine tellurique croit avec la pratique de plus en plus fréquente de la monoculture, principalement dans les régions méditerranéennes où, pour profiter des conditions climatiques exceptionnelles, la culture sous abri se développe considérablement. L'accumulation des parasites rend indispensable les traitements de sol et l'expérience acquise en ce domaine s'étend progressivement aux cultures de plein air. L'article passe rapidement en revue les principales maladies provoquées, en région méditerranéenne, par les champignons et bactéries du sol, ainsi que par certains virus transmis par les champignons du sol. La désinfection du sol par la vapeur, et surtout par l'utilisation de fongicides fumigants (bromure de méthyle et produits è base de métam‐sodium principalement), constitue le mode de traitement le plus répandu. Doués d'un large spectre d'efficacité, ces fongicides éliminent ou réduisent la plupart des champignons, souvent sans modifier profondément l'équilibre biologique des sols traités. Grace à l'évolution du matériel d'épandage des fumigants, on entrevoit leur application sur de grandes surfaces. A ces interventions chimiques s'ajoutent également les méthodes de lutte biologique qui découlent des connaissances acquises par l'étude des sols suppressifs. Déjà pour la tomate et l'oeillet, ces applications deviennent imminentes pour lutter contre la fusariose vasculaire. Quel sera l'avenir de la solarisation susceptible de concurrencer les fumigants? Les facteurs économiques prédomineront dans le choix de la méthode. Pour les cultures sous abri, privilégiées dans les pays méditerranéens, l'adoption de cultures hors‐sol en substrats constitue l'une des méthodes de lutte les plus efficaces contre les parasites d'origine tellurique et apporte en meme temps une plus‐value considérable par rapport aux cultures traditionnelles.
Etude de l'évolution de la mycoflore du sol de tomate en serre non chauffée après désinfection1
Authors: BOURBOS E. A.
Published: April 2008

L'équilibre de la mycoflore du sol de culture de tomate en serre, après désinfection au bromure de méthyle, subit une perturbation importante, jusqu'à la profondeur de 30 cm. Dans nos essais, 4 jours après le traitement du sol, la mycoflore saprophytique était représentée par Aspergillus alutaceus, Paecilomyces lilacinus, Penicillium chrysogenum, P. funiculosum, P. herquei, P. nigricans et Trichoderma viride, champignons apparemment tolérants ou résistants alors qu'en majorité la mycoflore parasitaire n'était pas isolée à partir du sol traité. Cette constatation permet d'envisager l'utilisation de ces saprophytes connus comme antagonistes, pour lutter contre les champignons phytopathogènes des racines de la tomate. La mycoflore parasitaire commencait à réapparaitre 12 jours aprés la désinfection (Alternaria alternata et Verticillium albo‐atrum); celle de la zone située à 30–40 cm de profondeur n'était pas influencée par le traitement. Pourtant certains champignons pathogènes présents dans cette zone (Colletotrichum coccodes, Fusarium moniliforme, F. oxysporum, F. solani, Pyrenochaeta lycopersici, V. albo‐atrum, V. dahliae) peuvent ravitailler les couches supérieures et provoquer des dégats sur le système racinaire de la tomate.
Maladies fongiques et bactériennes du fraisier1
Authors: D'ERCOLE N.
Published: April 2008

Les maladies fongiques et bactériennes représentent de sérieuses limites tant pour la production que pour le développement de la culture du fraisier. Les maladies de l'appareil racinaire sont les plus importantes et les plus préoccupantes. Cette étude décrit les maladies les plus fréquentes et indique pour chacune d'elles les méthodes de lutte, en traitant successivement les différentes parties de la plante: feuilles, fruits, collet et rhizome. Un schéma des traitements antifongiques recommandés est présenté.
Les ravageurs du fraisier dans les régions circum‐méditerranéennes1
Authors: MARTELLI M.
Published: April 2008

L'article passe en revue les ravageurs les plus importants du fraisier, groupés par référence à la partie de la plante attaquée (racines, collet, feuilles, fleurs et fruits). La mise en oeuvre de techniques modernes de production (remplacement des systèmes pérennes par la culture annuelle) a apporté d'important changements dans la composition des ravageurs. Ceci est vrai surtout pour les divers curculionides dont les larves radicicoles rendaient la culture pluri‐annuelle difficile. En ce qui concerne la lutte, il est essentiel de pratiquer les traitements chimiques au bon moment, si possible à l'aide de produits sélectifs, d'assurer une bonne pratique culturale (exemple de Tetranychus urticae) et de développer des systèmes intégrés pour lesquels le cultivateur devrait recevoir des instructions précises mais simples. Enfin, mention est faite de l'intéret que présente la disponibilité de matériel de plantation sain.
Influence de traitements effectués contre Ostrinia nubilalis avec la deltaméthrine sur l'entomofaune et les pucerons du maïs1
Authors: ROA L. , BOCQUET J. C. , BAUMEISTER R.
Published: April 2008

La deltaméthrine appliquée en pulvérisation à la dose de 20 g ha‐1 au stade 1 mà 1,20 m du maïs exerce une toxicité marquée sur une population de syrphes en phase d'installation. Le traitement a un effet également négatif sur microhyménoptères adultes, mais neutre en revanche sur une population de Scymnus arrivant 3 semaines plus tard. Le chlorpyriphoséthyl appliqué au stade ‘70% panicules visibles’a un impact plus limité que la deltaméthrine sur syrphes et microhymenoptères, par contre sa toxicité est plus marquée à l'égard de Scymnus. Comme, pendant toute la durée de l'essai, la population de Rhopalosiphum padi dans les deux parcelles traitées est restée inférieure ou comparable à celle du témoin, l'hypothèse d'une relation entre la destruction de certains auxiliaires et la proliferation de pucerons n'est pas vérifiée. Néanmoins, dans trois des 15 essais sur la valeur pratique de la deltaméthrine contre O. nubilalis menés en France en 1980–1983, les populations de pucerons ont augmenté significativement en fin de saison. Les causes du phénomène sont encore mal percues.
Influence de différents paramètres agronomiques et climatiques sur l'efficacité de quelques pyréthrinoïdes de synthèse1
Authors: HERVÉ J. J. , GAMAL A. , RUMEUR Cl. Le
Published: April 2008

L'expérience acquise durant plusieurs années en Egypte dans la lutte contre Spodoptera littoralis a prouvé que ce que l'on qualifie souvent de résistance est en fait un processus multiple qui dépend de l'alimentation et des conditions d'environnement, et non de facteurs génétiques. Lorsque l'on modifie le type de substrat alimentaire (differentes espèces végétales), le taux d'engrais azoté, la photopériode et la température, il faut souvent multiplier la DL50 par 5 ou 6.
Essais d'utilisation hivernale de la deltaméthrine (Décis et K‐Othrine EC 15) en forêt contre Thaumetopoea pityocampa1
Authors: DEMOLIN G. , MARTIN J.‐C.
Published: April 2008

D'après les essais effectués en 1984 et 1985, un traitement hivernal à la deltaméthrine (2,5 g m.a. ha‐1) est efficace contre Thaumetopoea pityocampa. Ces interventions réalisées en forêt par hélicoptère (ULV à 31 ha‐1) et dans les conditions normales de la pratique montrent que l'incidence sur la faune auxiliaire est particulièrement réduite en période hivernale.
The use of plastic bags as closed containers in screening for resistance to potato cyst nematode (Globodera rostochiensis and G. pallida)1
Authors: MARSHALL J. W. , GALLAGHER D. T. P. , SPINK M.
Published: April 2008

The use of a plastic bag as a closed container to screen for resistance in potatoes to potato cyst nematode in a controlled environment is described. Procedures to standardize the material tested and the inoculum used are outlined and the advantages of the system are discussed.
Experiences withBursaphelenchus xylophilusin Finland1
Authors: RAUTAPÄÄ J.
Published: April 2008

In 1984 a heavyBursaphelenchus xylophilusinfestation was observed in pinewood chips imported from USA and Canada into Finland. Because there are good reasons to suppose thatB. xylophilus, if spread to pine forests in North Europe, can cause significant damage, the import of coniferous wood into Finland has been prohibited since autumn 1984. In surveysB. xylophilushas not been found in roundwood or in chips imported from European countries into Finland. Neither hasB. xylophilusbeen detected in Finnish pine trees around harbours nor in paper mills handling North American wood.
Threats created by import of timber and chips into Norway1
Authors: VENN K. O.
Published: April 2008

In recent years, Norwegian forest industries have depended to some extent on imported coniferous timber and chips, which has to be debarked to fulfil phytosanitary requirements. However, the standard of debarking of logs and chips from North America is often low. Sunken areas on stems often develop from cankers or rot around knots, and often escape debarking. Besides, even debarked, timber and chips may carry dangerous pests (Inonotus weirii, Bursaphelenchus xylophilus). Precautions should be taken after landing to hinder further spread of such dangerous organisms.
Survival of Bursaphelenchus xylophilus in wood chips1
Authors: KINN D. N.
Published: April 2008

Preliminary results are presented on elimination of Bursaphelenchus xylophilus from pine wood chips by dry heat, hot water treatment and immersion in dithiocarbamate solution.
Seiridium cardinale and other cypress cankers1
Authors: GRANITI A.
Published: April 2008

Several species of microscopic fungi have been associated with canker diseases of wild and cultivated species of Cupressus and related genera. Seiridium cardinale was first reported in Europe (France) in 1944 and then spread to other countries, causing what at present is the major disease of cypress in Europe. Over the last two decades, heavy losses have been caused to the nursery industry, to cypress plantations used for forestation and windbreaks as well as to ornamental cypresses. The death of millions of trees has devastated the traditional and beloved landscape of areas where cypresses constitute a major element of the vegetation. Lepteutypa cupressi (anamorph Seiridium cupressi) has recently been reported in Greece (Kos). It had already caused considerable losses on cypress plantations in other geographical areas (Africa, Australia, Oceania). Some taxonomic aspects of the pathogen are discussed. The introduction of L. cupressi into the Mediterranean area, where S. cardinale has already spread, not only represents a serious threat to European cypress plantations, but also complicates the efforts made up to now towards the selection of resistant clones and the improvement of genetic resistance of the Mediterranean cypress C. sempervirens to S. cardinale. Thus, immediate action is required in order to eradicate the existing foci and to avoid further spread of the disease. Seiridium unicorne was first described in the USA in 1878 and then recorded again in North America, Europe, Asia and Oceania. The host range of this pathogen is not restricted to Cupressaceae and includes plants belonging to eight families. It seems that the canker disease due to S. unicorne is not so serious as that caused by S. cardinale or L. cupressi. L. cupressi has probably been misidentified as S. unicorne in records of epidemics in East Africa and other areas of the world.
Present phytosanitary situation of Portuguese forests
Authors: NEVES N. , MONIZ F. , DE AZEVEDO N. , FERREIRA M. C. , FERREIRA G. W. S.
Published: April 2008

Surveys carried out in conifer stands in the Azores and on the Portuguese mainland identified fungi causing serious new damage to pines and other conifer species. The most important are Dothistroma septospora found on needles of Pinus spp., Seiridium cardinale causing stem and twig canker of cypress and a new pathogen of the genus Elytroderma infecting needles of Pinus pinea with a subsidiary effect on stem and branches. After fires, new pathogens appeared in P. pinaster stands in North Portugal. Surveys in burnt plots showed the presence of the two very important root parasites, Rhizina undulata and Heterobasidion annosum, as well as species of the Ceratocystis complex producing not only blue stain, but also a wilt disease. Forest fires are often also associated with scolytid attacks on P. pinaster, specially by Tomicus piniperda, T. minor and Ips sexdentatus.
Occurrences of Ceratocystis ulmi in Norway1
Authors: VENN K. O.
Published: April 2008

Norway (in contrast to Denmark and Sweden) has so far had only a few outbreaks of Dutch elm disease, all in the southern part of Norway (cities of Oslo and Drammen) on one or a few Ulmus glabra trees in city parks, not far from harbours and railways. Scolytus laevis endemic to Norway is the only potential vector found in the diseased trees. Transmission of the fungus through root grafts cannot be disregarded. The fungus is currently considered a dangerous foreign organism in Norway, subject to treatment according to the Norwegian phytosanitary regulations. Control measures, aiming at eradication, have been applied in all known cases of attack. Removal and destruction of diseased trees, stump treatment with herbicide, and covering of stumps with soil, have apparently been successful measures.
Sanitation campaign against Ceratocystis ulmi in The Netherlands1
Authors: WATER J. K.
Published: April 2008

The introduction and rapid spread of the aggressive strain of Ceratocystis ulmi in The Netherlands led to development of a 100% subsidised nationwide felling campaign. Since 1978, all elms have been assessed twice a year for health and viability, and diseased trees have been destroyed within a month. This limited losses to 1% of the important elm clones planted along roads, but at high annual cost (6 million F1) because of the need also to destroy diseased field elms. In future, long‐term costs will be reduced by destruction of the less important field elms in the west of the country. In the east, the campaign has been abandoned (with some exceptions round cities).
Le problème des Ceratocystis européens des chênes1
Authors: DELATOUR C.
Published: April 2008

Tenant compte des données de la littérature classique ainsi que d'informations plus récentes, l'auteur fait état des limites qui demeurent dans la connaissance des Ceratocystis européens des chênes et de leur intervention éventuelle en tant que pathogènes dans les phénomènes de dépérissement. Certaines de ces interrogations, sans réponse depuis de nombreuses années, devraient faire l'objet de recherches concertées au niveau européen.
Les maladies du platane, avec référence particulière au chancre coloré; situation actuelle en France1
Authors: VIGOUROUX A.
Published: April 2008

Plus que d'autres espèces, le platane a vu récemment s'élargir l'éventail de ses parasites au point de devenir menacé. Depuis longtemps existaient partout en France plusieurs types d'affections: le champignon Gnomonia veneta qui défeuillait sévèrement les arbres lors des printemps frais et certains champignons lignivores. Mais se sont ajoutés depuis quelques années deux parasites foliaires notables, le champignon Microsphaera platani (oïdium) et l'insecte piqueur Corythuca ciliata. Enfin et surtout, se développe actuellement dans l'extrême sud‐est du pays le redoutable parasite Ceratocystis fimbriata f.sp. platani, agent de la maladie du chancre coloré. Introduite à Marseille à la fin de la Seconde Guerre mondiale, la maladie est restée longtemps relativement localisée, mais connaît depuis quelques années une phase d'extension active. Des trous se créent dans des alignements de plusieurs petites villes de Provence et, ponctuellement, des peuplements importants ont été anéantis. En plus de la transmission par les outils d'élagage ou les chocs divers, on a constaté une transmission directe par contacts racinaires et des possibilités importantes de transport et de contamination par l'intermédiaire des engins de terrassement. D'énergiques mesures prophylactiques prenant en compte ces divers éléments commencent àêtre mises sur pied et des travaux de sélection de clones résistants sont envisagés.
Situation d'Hypoxylon mammatum en Europe1
Authors: PINON J.
Published: April 2008

Hypoxylon mammatum, agent du chancre des peupliers de la section Leuce est vraisemblablement présent depuis longtemps en Europe (Andorre, France, Grande‐Bretagne, Italie, Suède et Suisse). En conditions naturelles, son incidence est importante surtout en régions montagnardes. Il constitue par ailleurs une menace sérieuse pour les trembles hybrides et les grisards artificiels dont la mise en culture en France est actuellement précédée d'une sélection pour la résistance.
Champignons pathogènes sur graines forestières1
Authors: MOTTA E.
Published: April 2008

S'il est bien connu que les champignons sont capables de s'installer à la surface ou dans les différents tissus de la graine, on ne dispose que de peu d'informations sur la présence de micro‐organismes sur semences de plantes forestières, mais trois types de champignons sont à considérer: (1) les champignons très communs, considérés couramment non pathogènes, mais qui peuvent, le cas échéant, provoquer une baisse de germination; (2) les champignons pathogènes spécifiques, qui attaquent les tissus de la graine et la plantule; ils causent un dégât direct à la pépinière et peuvent se diffuser, grâce au commerce des semences, dans une zone auparavant indemne; (3) les champignons pathogènes, pas forcément spécifiques, qui causent des dégâts à la plantule issue de la graine sur laquelle ils étaient présents et, en plus, sont capables de provoquer des fontes de semis. En ce qui concerne l'Italie, quelques observations ont été effectuées sur la présence de Seiridium cardinale sur semences de Cupressaceae et celle de Fusarium moniliforme et de F. moniliforme var. subglutinans sur semences de Pinus pinaster.
The elm bark beetle Scolytus kirschi and its control in Israel1
Authors: HALPERIN J.
Published: April 2008

Scolytus kirschi, a bark beetle new to Israel, was found in 1983 near Lake Kinneret affecting and killing young elm trees under stress. The main cause of the stress was water deficiency. Phytosanitation, seasonal irrigation and exposure of trap logs all slowed down the spread of the beetle and prevented further damage.
Attacks of Neodiprion sertifer on Pinus contorta1
Authors: HAYES A. J. , BRITTON R. J.
Published: April 2008

Neodiprion sertifer, the European pine sawfly, has in the past attacked mainly Pinus sylvestris. Afforestation of areas in northern Scotland with P. contorta in the early 1960s and subsequently has led to widespread outbreaks of N. sertifer on this species, attacks being most severe on trees 5 to 12 years old. The most serious damage is removal of the 1‐year and older needles. Complete loss of this foliage often occurs at the peak of an outbreak. Also, at high population densities, larvae may consume patches of bark, leading to weakening and stem breakage in high winds. Field studies comparing protected (undefoliated) randomized plots of P. contorta with defoliated plots in Shin Forest (Sutherland) were carried out over the 1982–1983 growing seasons. Comparison of leaf/sapwood basal areas in undefoliated and defoliated plots indicated losses of up to 27% of total leaf area, both removal of old foliage by larvae and a reduction in current‐year foliage being involved. Further, there were significant reductions in sapwood basal area and height increment between control plots and some of the defoliated plots. The impact of such defoliation is to prolong the rotation by approximately 2 years.
Current status of Corythuca ciliata in Europe1
Authors: MACELJSKI M.
Published: April 2008

Corythuca ciliata, a N. American heteropteran, has been spreading on plane in Europe since 1964 and is now certainly present in Italy, Yugoslavia, France, Hungary, Spain, Austria and Switzerland, and probably in some other countries. Besides weakening the trees, the insect much diminishes their amenity value and is a direct nuisance to man. Its biology and control are reviewed, with emphasis on the possibilities for a biological or integrated approach (IOBC/WPRS working group). Though several countries remain uninfested, the insect's capacity for natural spread makes it unlikely that phytosanitary measures would serve much purpose.
A note on the parasite complex of Thaumetopoea pityocampa in Yugoslavia1
Authors: HARAPIN M.
Published: April 2008

Egg, caterpillar and cocoon parasites of Thaumetopoea pityocampa, the most important pine pest of the Adriatic area, were identified and counted in six experimental plots over a 5‐year period.
Application of pityolure for detection and control of Thaumetopoea pityocampa in Israel1
Authors: HALPERIN J.
Published: April 2008

Trials were carried out with pityolure, the synthetic female sex pheromone of Thaumetopoea pityocampa, to test the various possibilities of its use in the management of the pest. Practical application consists of macromapping of infested and non‐infested areas, early detection of new foci of infestation, and timing of sprays with insecticides. Brief mention is made of possible uses not yet applied in practice, such as control by mating disruption, control by mass trapping and monitoring of the population level.

Des essais sur le pityolure, phéromone synthétique sexuelle femelle de Thaumetopoea pityocampa, ont permis de tester diverses possibilités d'utilisation pour la lutte contre cet organisme nuisible. Parmi les applications pratiques sont la macro‐cartographie des lieux infestés ou non infestés, la détection précoce de nouveaux foyers d'infestation et la détermination des dates d'application de pulvérisations d'insecticides. Quelques utilisations possibles mais non encore appliquées sont brièvement mentionnées: lutte par confusion des mâles, lutte par piégeages en masse et contrôle des niveaux de population.
Detection of latent infection of Erwinia chrysanthemi and Pseudomonas caryophylli in carnation1
Authors: MURATORE M. G. , MAZZUCCHI U. , GASPERINI C. , FIORI M.
Published: April 2008

Three methods for detecting latent infections of Erwinia chrysanthemi and Pseudomonas caryophylli in carnation stems were studied. The same procedure was used, in all three methods, to prepare the samples and to extract and concentrate bacteria. The samples consisted of 100–500, 1‐cm‐long, pieces of carnation stems. Under the standard procedure, the samples were homogenized in maceration fluid, then centrifuged at low speed to eliminate the larger tissue fragments and centrifuged again at high speed to obtain a final pellet with a maximum concentration of the bacteria to be detected. Immunofluorescence staining (IFAS), direct isolation (DI) and immunoenzymatic test (ELISA) were all applied to the final pellets. IFAS had a sensitivity threshold equal to 8.65 × 104 and 3.33 × 104 bacteria per 100 stem pieces for E. chrysanthemi and P. caryophylli. In simulated latently infected lots IFAS could detect down to 0.2% infected pieces for both pathogens, both at high and at low infection level. Although DI had a similar theoretical sensitivity threshold for both bacteria, it was less successful when applied to simulated latently infected lots. ELISA had the highest theoretical sensitivity threshold for both bacteria and as a consequence could only detect them in simulated latently infected lots with a high infection level. The comparative results are discussed in relation to the applicability of the methods to commercial lots of carnation.
Caractérisation des Erwinia chrysanthemi isolées de Solanum tuberosum et d'autres plantes‐hôtes selon les biovars et sérogroupes1
Authors: SAMSON R. , POUTIER F. , SAILLY M. , JOUAN B.
Published: April 2008

Des pourritures et flétrissements bactériens dus àErwinia chrysanthemi sont inventoriés aujourd'hui sur plus de 25 espèces de plantes cultivées (dont la pomme de terre depuis 1971) et dans de norabreux pays tempérés ou tropicaux. Cette diversité géographique et de gamme d'hôtes mérite des études approfondies. L'espèce bactérienne E. chrysanthemi est subdivisée dans le Bergey's Manual de 1984 en six pathovars: chrysanthemi, dianthicola, dieffenbachiae, paradisiaca, parthenii et zeae. Que faire des E. chrysanthemi isolées de pomme de terre, tomate, endive, artichaut? Au lieu de classer les isolats en pathovars, il paraît souhaitable, car simple et fiable, d'adopter le classement en biovars d'après des critères physiologiques de laboratoire mis en évidence ces dernières années, et qui se révèlent discriminants (croissance à 39°C; hydrolyse de l'arginine selon Moeller, de la lécithine et de la gélatine; utilisation des sources de carbone suivantes: cis‐aconitate, D(‐)arabinose, 5‐cétogluconate, inuline, mannitol, mélibiose, raffinose, D(‐)tartrate). Il est également important, avant d'entreprendre une détection par sérologie, de connaître l'appartenance des isolats aux sérogroupes connus (antigènes de paroi) et leur type flagellaire.
The distribution of potato spindle tuber viroid in potato plants and tubers1
Authors: WEIDEMANN H.‐L.
Published: April 2008

Potato spindle tuber viroid (PSTV) in potato plants was investigated by ‘return’ gel electrophoresis. The experiments were carried out under quarantine conditions in the greenhouse with primarily and secondarily infected plants. The PSTV content in different plant parts was estimated by the intensity of the viroid band in polyacrylamide gel. The results showed a decrease of viroid content from the upper to the lower parts of the plant. In both primarily and secondarily infected plants, PSTV was reliably detected in the top leaves, but less so in the lower leaves. In four out of ten secondarily infected plants, PSTV was found in the roots. In dormant tubers, the bands were more intense with samples obtained from the rose end and the heel than from those obtained from the medullary tissue. With one exception, all 64 tubers from 26 primarily infected plants were infected with PSTV.
Exclusion of viroids from potato resources and the modified use of a cDNA probe1
Authors: HARRIS P. S. , JAMES C. M.
Published: April 2008

Threats from potato spindle tuber viroid (PSTV) to potato breeding and centralized elite seed‐tuber production have been identified in world potato genetic resources. In the UK effective diagnostic testing has proved essential in preventing acquisition. Inoculation of potato nucleic acids to tomato and subsequent viroid detection by polyacrylamide gel electrophoresis (PAGE) has proved a sensitive, but cumbersome, test over 8 years. Additionally, over 2 years, 32P‐labelled PSTV cDNA was used to probe denatured sap and nucleic acid extracts: 10‐4 of peak viroid concentrations in tissue could be detected. Spurious positives were seen in particular circumstances, but could be avoided. Probing of non‐denatured samples was not as sensitive. Tubers became infected and PSTV was readily detected by PAGE in leaves of potato experimentally inoculated and maintained below 20°C, but the cDNA probe could not detect infection in tuber sprouts growing at 8–10°C in darkness. Otherwise similar green‐leaved sprouts were faintly positive. Detection for all sprouts was unproblematic after movement to 25°C and light for 10 days.
Detection of potato virus Y in early‐harvested potato tubers by cDNA hybridization and three modifications of ELISA1
Authors: DE BOKX J. A. , CUPERUS C.
Published: April 2008

The standard ELISA method for detection of PVY in dormant potato tubers was compared with recently developed methods: (1) a hybridization technique, using a complementary DNA‐probe to PVYN; (2) three modifications of ELISA (standard monoclonal, Flegg & Clark polyclonal or monoclonal). Sap of six Dutch cultivars secondarily infected with PVY was subjected to these methods directly after lifting and after six subsequent one‐week intervals during storage at 20°C. During storage the detectability of PVY decreased, irrespective of the diagnostic method applied. However, decrease was less in susceptible than in resistant cultivars. Although the hybridization technique yielded slightly better results than the standard ELISA procedure, it was time‐consuming and involved hazardous reagents. The modifications of ELISA investigated were not, in general, more sensitive than standard ELISA.
Comparaison de trois méthodes de broyage d'échantillons végétaux destinés au test ELISA1
Authors: MATHON M. P. , TAVERT G. , MALATO G.
Published: April 2008

La detection des virus dans les végétaux par la technique immunoenzymatique ELISA exige une certaine préparation des échantillons et la phase de broyage demeure actuellement le principal facteur limitant la réalisation d'un grand nombre de tests journaliers. La présente étude compare les trois techniques les plus souvent disponibles dans un laboratoire: (1) le broyage par disperseurs‐homogénéisateurs travaillant à vitesse très élevée (type Polytron/Kinematica ou Ultra Turrax; (2) l'utilisation d'une presse dans laquelle l'échantillon est écrasé lentement entre deux rouleaux tournant en sens contraires (type MEKU Pollähne); (3) le broyage d'un échantillon conditionné entre deux épaisseurs de gaze dans un sachet individuel de plastique. La dilacération des tissus est assurée par un dispositif à roulements à billes monté sur une perceuse (système Tekan/Inotech). C'est cette dernière technique alliant simplicité, économic et rapidité qui convient ainsi le mieux à un laboratoire assurant en routine ce type de tests.
Detection of Corynebacterium michiganense in tomato seed lots1
Authors: VAN VAERENBERGH J. P. C. , CHAUVEAU J. F.
Published: April 2008

Corynebacterium wilt of tomato causes severe losses in France and Belgium. The disease can be seed‐transmitted and sanitary selection of seedlots is a direct prophylactic control method. It must be selective, objective and sensitive and must provide information on the pathogenicity of the bacteria detected. A method is proposed that associates immunofluorescence (IF) staining with bioassay and isolation. In a preliminary comparison of inoculation on different host plants, tomato seedlings with two or four leaves were the most sensitive. Artificially and naturally contaminated seed extracts were IF‐screened and confirmed by isolation of the pathogen from inoculated seedlings. The detection method consists of maceration of tomato seeds in PBS‐cycloheximide buffer, filtration and centrifugation of the seed extract, and IF screening of the pellets with two antisera. Pellets with positive or suspect IF reading (threshold 5 × 103 cells in the pellet) are inoculated into tomato seedlings incubated at 25°C. Within 30 days the seedlings are inspected for typical wilt symptoms and isolation experiments are carried out from the vessels. The method has been tested on commercial seedlots.
New approach in detecting phytopathogenic bacteria by combined immunoisolation and immunoidentification assays1
Authors: VAN VUURDE J. W. L.
Published: April 2008

Antibodies coated onto a suitable solid phase, e. g. polystyrene beads, rods for inoculating agar plates, or petri dishes, enable selective trapping of homologous bacteria and of immunologically related bacteria by immunoaffinity. After washing away unbound organisms, the bound organisms are desorbed and plated on a suitable medium. Selective immunoisolation has been demonstrated for various phytopathogenic bacteria including Corynebacterium michiganense ssp. michiganense, Erwinia chrysanthemi, E. carotovora ssp. atroseptica, Xanthomonas campestris pv. begoniae and Pseudomonas syringae pv. phaseolicola. Three serological methods are described for additional rapid immunoidentification of colonies directly on agar plates and for screening for cross‐reacting microorganisms: (a) direct immunodiffusion on dilution plates, (b) agar mixed‐antibody assay, (c) fluorescent antibody colony staining. Schemes are presented for increasing the reliability and sensitivity of sample screening for quality indexing of plant material, and for efficient screening and isolation of possible cross‐reacting microorganisms to enable production of more specific antisera.
Evolution et situation du feu bactérien en France1
Authors: BOUÉ H.
Published: April 2008

Entre 1972 et 1982, le feu bactérien est apparu successivement dans le nord de la France, l'Aquitaine et l'Alsace. De nouveaux foyers se sont développés en 1983 et 1984 dans plusieurs autres régions de la moitié ouest du pays. La maladie affecte surtout les vergers de poiriers. Elle est également observée sur les plantes‐hôtes ornementales dans les espaces verts de certaines villes, et parfois en pépinières. Sur aubépine, elle est fréquente dans les régions du nord de la France. Différentes mesures ont été mises en place afin de réduire les foyers et d'éviter leur extension.
Present status of fireblight in the Federal Republic of Germany1
Authors: ZELLER W.
Published: April 2008

The three phases of spread of fireblight in FRG are described, from its first appearance in 1971 to the present day. The disease is now well established in Schleswig‐Holstein and Niedersachsen and scattered outbreaks have occurred over the whole of the rest of the country (but only one in Bayern). The control strategy now centres on destruction of diseased plants within 500 m of any outbreak found in an orchard or nursery (object protection).
Recent research progress on Xanthomonas ampelina1
Authors: PANAGOPOULOS C. G.
Published: April 2008

Bacterial blight of grapevine (caused by Xanthomonas ampelina) occurs in Greece, France, Spain, Italy, Turkey, Portugal, USSR and South Africa. It is a serious, chronic vascular disease which is widespread in some areas of grape production, affecting commercially important cultivars. There is evidence that the disease is presently spreading into new areas in some countries. The actual distribution of blight may be much wider, since its symptoms may be confused with those of other diseases. It is therefore essential to confirm the presence of X. ampelina by isolation and identification. X. ampelina is an anomalous member of the genus Xanthomonas which is readily distinguished on the basis of a few tests. The pathogen may also be rapidly detected in grapevine sap using the indirect immunofluorescence technique. The susceptibility of shoots to infections, under Cretan conditions, is highest from November to late January and very low during February and March. It has been found that up to 50% of apparently healthy canes obtained from diseased vineyards were latently infected. Transmission of the pathogen through soil and roots during the control of Daktulosphaira vitifolii or frost damage by flooding has been demonstrated in France. Several of the more widely grown cultivars were found to be very susceptible to the pathogen while no completely resistant cultivar has been detected. Control trials based on four sprays with a number of chemicals were unsuccessful. Control policy should be directed: (a) to preventing spread of the disease, by exclusive use of certified material; (b) to minimizing the disease in affected areas by suitable sanitary, cultural and preventive measures.
Current status of Xanthomonas ampelina in Spain and susceptibility of Spanish cultivars to bacterial necrosis1
Authors: LÓPEZ M. M. , GRACIA M. , SAMPAYO M.
Published: April 2008

The causal agent of bacterial necrosis of vine, Xanthomonas ampelina, was first recorded in Spain in 1978 on grapevines in the region of Zaragoza, where the total infested area is now around 9000 ha. The disease was later recorded in Rioja where small foci of around 50 ha were found, and in Galicia, where it exists in the area of Ribeiro and Pontevedra. Surveys done in other grapevine‐growing areas of the country have not led to the detection of the disease. The symptoms described in Spain are the same as those in other countries and bacterial necrosis has not, at present, been identified on table grapes. Losses resulting from the disease are closely linked to climatic conditions and the drought of these last few years has practically eliminated symptoms of X. ampelina in Aragon and the area of Rioja. Chemical control of the disease through the use of cupric formulations is not sufficient during rainy years with favourable conditions, and the best method for preventing the disease seems to be the use of resistant cultivars or those displaying weak susceptibility. A 3‐year experimental field study of the varietal susceptibility of 30 Spanish cultivars has shown that Airén, Garnacha tintorera, Juan Ibáñez and Vidadillo are the most susceptible. Cardinal, Garnacha negra, Mazuela, Merseguera, Monastrell and Trepat are the least susceptible of all the cultivars studied. A parallel study of the susceptibility of plants grown in vitro has been undertaken and may be useful for rapid testing of varietal susceptibility.
Le dépérissement bactérien (Pseudomonas spp.) de l'abricotier: situation en France1
Authors: PRUNIER J. P. , COTTA J.
Published: April 2008

Le dépérissement bactérien de l'abricotier prend progressivement de l'importance en France avec le développement de cette culture. L'étude récemment entreprise sur cette maladie fait apparaître une situation complexe, car trois espèces bactériennes appartenant au genre Pseudomonas sont associées aux dégâts: P. syringae pv. syringae, P. viridiflava et P. syringae pv. mors‐prunorum. La maladie se présente sous trois formes principales succintement décrites. Le rôle de certains facteurs liés au milieu physique (froid) ou au matériel végétal (porte‐greffe) est discuté et fait l'objet d'études en cours.
The problem of bacterial canker of hazelnut in Greece caused by Pseudomonas syringae pv. avellanae1
Authors: PSALLIDAS P. G.
Published: April 2008

The present situation of the disease in Greece and its main aspects, causal agent, symptomatology, epidemiology and control measures are described. The characteristics differentiating the pathogen from some other Pseudomonas species are also reported.
Problems of Agrobacterium tumefaciens in planting material and its control1
Authors: GARRETT C. M. E.
Published: April 2008

Crown gall caused by Agrobacterium tumefaciens is a problem in many European nurseries especially on stone fruits, apples and some herbaceous hosts (biovars 1 and 2) and on grapevines (biovar 3). Nursery infection can arise from land infested with the pathogen. Disease incidence can be reduced to some extent by cultural methods such as crop rotation, minimizing wounding and selection of less susceptible cultivars. The best control of infection is the use of a pre‐planting dip in the antagonist A. radiobacter strain 84, which gives excellent control of strains of the pathogen harbouring the nopaline‐type Ti plasmid. The antagonist is not yet cleared for use in all European countries. This biological control is sometimes ineffective because of the presence of mixed populations of sensitive and resistant strains of the pathogen, use of too low inoculum doses of the antagonist or because the host plant affects the antagonist action. All controls are preventive and not curative, so latent infections in layer or stool beds cannot be prevented from developing. Control of the strains of the pathogen insensitive to strain 84 may be possible in future by the use of other antagonistic organisms or by genetic manipulation of strain 84. Until such a new development becomes available, growers must make careful selection of propagating material to minimize the risk of spreading infection.
Results of seven years of biological control of Agrobacterium tumefaciens in Spain1
Authors: LÓPEZ M. M. , GORRIS M. T. , TEMPRANO F. J. , ORIVE R. J.
Published: April 2008

Biological control of Agrobacterium tumefaciens using the K84 strain of A. radiobacter has been practised in Spain since 1979. Strain K84 is produced in Sevilla by the Agricultural Research Service and is mixed with peat. This formulation is authorized for use on stone fruits and roses, since results of various trials on rootstocks of these crops have shown that K84 is effective in controlling the disease in naturally infected nursery soil, as well as in experimental tests carried out on artificially inoculated soil. Results of biological control trials have shown that K84 has some effect on A. tumefaciens strains resistant to agrocin 84. Factors other than susceptibility to agrocin 84 influence the efficacy of biological control. This was demonstrated by using a K84 agrocin non‐producer strain which proved effective against both resistant and susceptible strains. Biological control on apple or pear is not yet authorized in Spain due to a paucity of data on field trials. However, initial pot tests showed good K84 activity on these hosts, against Spanish strains of A. tumefaciens. On grapevine, most of the A. tumefaciens strains that were isolated belong to biotype 3 and are resistant to agrocin 84. Because the disease is systemic on this species the use of K84 is not authorized.
A bacterial leaf spot of wisteria in Italy1
Authors: VARVARO L.
Published: April 2008

Bacterial leaf spot was observed on Wisteria sinensis in the south of Italy. Lesions on leaflets were small, round, dark brown, surrounded by an extensive yellow halo. Upon artificial inoculation, lesions similar to naturally occurring ones were reproduced. The causal organism was rod‐shaped, Gram‐negative, aerobic, motile by polar flagella, fluorescent. On the basis of morphological, biochemical and physiological tests, the bacterium was identified as Pseudomonas syringae pv. syringae.
Recent problems with Pseudomonas syringae pv. pisi in UK1
Authors: STEAD D. E. , PEMBERTON A. W.
Published: April 2008

Bacterial blight of peas caused by Pseudomonas syringae pv. pisi was found for the first time in a UK field crop during 1985. The outbreak was confined to a seed crop of the compounding protein pea cv. Belinda. All stocks derived from the original imported basic seed lot were traced and the seed crops from some 180 farms were removed from the certification schemes and were not allowed to go for planting. The pathogen, belonging to race 2, was found in approximately two thirds of these stocks. Protein pea seed is produced in UK, whereas most seed for vining crops is imported. The UK climate with its cool, wet summers is considered ideal for the establishment of pea blight and we consider that the disease could be particularly damaging in susceptible cultivars. Statutory control methods will be reviewed in an effort to maintain freedom from the disease. Surveys of field crops will also be carried out.
Strategies for combating fungicide resistance—avoidance of curative and eradicative applications
Authors: KABLE P. F.
Published: April 2008

The avoidance of curative or eradicative use has been recommended as one element in the strategy for combating the development of resistance against acylalanine fungicides. The concepts involved are discussed in relation to the mechanisms of fungicidal action and resistance development. This element in the strategy requires a more critical reformulation, and this in turn will depend upon new research and experience with resistance development. Practical and economic factors encountered in applying fungicide resistance management strategies are mentioned.
Evaluation des propriétés antagonistes de 11 souches de Trichoderma sur Botrytis cinereaà l'aide de plusieurs méthodes de laboratoire1
Authors: JAILLOUX F. , FROIDEFOND G.
Published: April 2008

L'étude du pouvoir antagoniste des spores et du mycélium de 11 souches de Trichoderma appartenant à neuf ‘species aggregates’ (classification de Rifai) a été réalisée sur les spores et le mycélium d'une souche de Botrytis cinerea résistante au bénomyl. Six gouttes contenant chacune une suspension de spores de Trichoderma (1, 10 ou 100 spores par μ1) et de B. cinerea (1 ou 10 spores par μl) sont déposées à la face inférieure d'une feuille de vigne du cv. Muscadelle placée en chambre humide à la température de 22°C. Dix jours après l'inoculation, les nécroses formées pour chacune des huit répétitions par traitement sont notées. La confrontation mycélienne d'une culture de B. cinerea et de chaque souche de Trichoderma pendant des temps variables à la température de 22°C a permis d'observer la vitesse de recouvrement du mycélium de B. cinerea et de vérifier sa viabilité après transfert sur un milieu contenant du bénomyl. Nous avons pu montrer qu'à l'égard de B. cinerea, le pouvoir antagoniste des spores de 11 souches de Trichoderma est semblable à celui de leur mycélium. Deux groupes de souches ont pu etre différenciés: sept souches très antagonistes appartenant aux espèces T. hamatum, T. harzianum, T. koningii, T. longibrachiatum et T. viride; quatre souches non antagonistes appartenant aux espèces T. aureoviride, T. polysporum, T. pseudokoningii et T. reesei.
Studies on the biological control of plant pathogens in Finland1
Authors: TAPIO E.
Published: April 2008

Studies on biological control of plant pathogens in Finland were started by Pohjakallio in the 1950s, concentrating especially on the microbes parasitizing fungal sclerotia. At the turn of the 70s, Kallio studied the protective effect of Finnish isolates of Phlebia gigantea against the most important forest pathogen Heterobasidion annosum with positive results. The preparation was put on the market. Later in the 1970s, the observation by Tahvonen that Finnish light‐coloured peat had an inhibitory effect on the infection of plants by some seed and soil‐borne fungal pathogens led to further investigations. Of the microbes isolated from peat, Streptomyces spp. proved the most effective antagonists in both in vitro and in vivo tests. Studies are in progress with S. griseoviridis and several other fungal and bacterial antagonists as potential biocontrol agents against some seed and soil‐borne pathogens and storage diseases.