bluuebunny/crossref_metadata_2025 huggingface dataset:
Potato Wart in the Federal Republic of Germany
Authors: LANGERFELD E.
Published: April 2008

A survey shows the present situation of the occurrence of potato wart (Synchytrium endobioticum) in the Federal Republic of Germany. By 1960 five different pathotypes (races) could be detected. Only 1 % of all foci identified after the Second World War belonged to the old pathotype 1 (← common race →). Questions of determination and emergence of new pathotypes as well as those of official restrictions on cultivar release are discussed.
Spread of the Musk‐Rat in the Federal Republic of Germany
Authors: PELZ H.J.
Published: April 2008

The spread of the musk‐rat in FRG is reviewed over the period since 1962. Very few areas are now free. While it has not been possible to prevent spread to the Bodensee area (lake Constance), a clear border has been established and maintained in Schleswig‐Holstein. In general, it would seem that populations are more affected by habitat and weather conditions than by trapping efforts and more work is needed on the real results of the trapping programme.
Costs and Benefits of Quarantine Measures against Liriomyza trifolii in Finland1
Authors: RautapäÄ J.
Published: April 2008

In order to prevent the entry of Liriomyza trifolii into Finland the importation of rooted chrysanthemum, gerbera, cucumber, tomato and lettuce plants is prohibited, as well as the importation of chrysanthemum cut flowers and leaves of gerbera. Unrooted chrysanthemums and gerberas must be cultivated in quarantine for two weeks before they are approved. During 1982 the total costs of this quarantine survey were 70,000 Fmk. Eradication of the pest has been more expensive; in 1980 its eradication from eight glasshouses caused total costs of 380,000 Fmk to the government, and in 1982 the corresponding figure with four glasshouses was 280,000 Fmk. The range of costs of chemical control in glasshouses growing vegetables and chrysanthemums while « living with »L. trifolii are estimated to be 0.8–8.8 million Fmk depending on whether 10 or 100 % of the growing area is to be treated. When all the costs caused by exclusion measures are summed (eradication + quarantine) and compared with the costs of « living with » the pest, the ratio will be 1: 3 to 1: 13 depending on the use of insecticides. The secondary effects of additional use of insecticides on biological control or marketing difficulties because of residues are not included in this comparison. In this case the most economical way of avoiding problems caused by L. trifolii is to invest in pre‐entry quarantine measures and prevent its spread into the country.
Containment and Eradication of Phytophthora fragariae in Sweden1
Authors: Gränsbo G.
Published: April 2008

Sweden is the only Nordic country in which Phytophthora fragariae is locally established. Growers and nurserymen have suffered severe financial losses in the last 5 years. Further spread is being limited by an intensification of the official compulsory certification scheme for strawberry planting material and by information, surveys and supervision of control. Imported material is subject to post‐entry quarantine.
Certification Schemes and their Benefit to Plant Protection1
Authors: Elhanan S.
Published: April 2008

In Israel, compulsory certification schemes have been of major importance in the protection of many crops. The examples discussed include carnation, rose, grapevine and avocado. Citrus certification in particular has provided an essential back‐up to the programme of eradication of citrus tristeza virus. New meristem‐culture techniques and virus‐testing methods will make such schemes easier to develop in future and open possibilities for internationally accepted schemes.
Establishment and Multiplication of Virus‐free Nuclear Stocks of Potatoes in Denmark1
Authors: Kristensen H. RØNde
Published: April 2008

A programme of meristem‐stem tip culture of potato was initiated in Denmark in 1977 to eradicate Corynebacterium sepedonicum and at the same time produce virus‐free stocks. The procedures for obtaining the cultures, and ksting for viruses, at the National Institute of Plant Pathology are described. The first tuber generation is further propagated for 2 years by the Research Institute for Potatoes at Tylstrup. Selected growers then multiply the « meristem potatoes » under the pre‐basic system for another 3 years, under the supervision of the National Committee for Health Control of Seed Potatoes.
Analyzing Cost Effectiveness of EPIPRE1
Authors: Zadoks J.C.
Published: April 2008

EPIPRE is an integrated pest and disease management system for wheat, fully computerized, based on on‐line calculations of costs and benefits of pesticide treatments; it is field‐specific and utilizes disease and pest monitoring in the field. The development of the project took five years (1977/1981). Cost effectiveness has been estimated in retrospect and in prospect using 1980 as a base year, covering the period 1977 through 1985. Future costs were disccrunted at a 10 % rate. The Net Present Worth of the project was estimated at nearly eight million Dutch guilders. The nonmeasurable effects of the project seem to be even more important than the measurable effect.
International Cooperation in Plant Protection1
Authors: Kristensen H. RØNde
Published: April 2008

Preventing the introduction of dangerous organisms into new countries and regions requires an international approach. The article reviews the most dangerous organisms for different continents, and describes in particular the procedures developed in Europe for assessing quarantine risks, through international cooperation within the European and Mediterranean Plant Protection Organization. The activities of EPPO are reviewed, and also those of the ISHS Plant Protection Commission, especially in relation to fruit‐tree viruses. The implementation of international cooperation within the European Community, and specifically in Denmark, is described.
The Prediction of Weed Infestations: Concepts and Approaches
Authors: Mortimer A.M. , Putwain P.D.
Published: April 2008

The role of studies on the population biology of weed species is examined and the utility of such studies in the design of weed management systems assessed. It is argued that the development of predictive models of the population behaviour of weed species is likely to be crucial to the critical evaluation of weed control programmes in the future. Illustrations are given of the dynamics of herbicide resistance in Senecio vulgaris and of the calculation of infestation rates of Agropyron repens under differing control managements.
Pratique francaise de la fumigation aux frontières: situation, évolution1
Authors: DUCOM P.
Published: April 2008

Le Service français de la protection des végétaux assure la surveillance phytosanitaire du territoire et des frontières, et est responsable du contrôle des fumigations. Les neuf principaux ports sont équipés d'installations d'une capacité totale de presque 2000 m3, travaillant sous vide partiel. Une nouvelle legislation autorise également la fumigation sous bâche ou dans le conteneur. Le bromure de méthyle reste le principal produit utilisé, l'HCN et l'oxyde d'éthylène servant à certains traitements spéciaux. La phosphine ne convient, ni au traitement sous vide, ni aux chaînes commerciales rapides. Toutefois, son utilisation pour le traitement des produits en transit pourrait présenter un grand intérêt si les problèmes de sécurité et d'efficacité peuvent être résolus.
Modern means and methods of plant product fumigation in the USSR1
Authors: MORDKOVICH Ya. B. , MENSHIKOV N. S. , LUZAN N. K.
Published: April 2008

Recent advances in fumigation technique in the USSR are reviewed. The problem of fumigation in containers is being approached by introduction of the gas through air‐holes. Mixtures of methyl bromide with carbon dioxide are being used increasingly against storage pests, and allow lower dosage rates and safer application conditions. Recent experience on quarantine fumigation of potato tubers against Phthorimaea operculella is reviewed, and finally research is reported on neutralizers and absorbents of methyl bromide used to facilitate degassing.
Fumigant doses for the control of Trogoderma granarium1
Authors: BELL C. H. , HOLE B. D. , WILSON S. M.
Published: April 2008

The diapausing larvae of Trogoderma granarium are among the most tolerant of all storage pests to fumigation and effective dosage schedules are required. For this purpose, the toxicity of methyl bromide (MeBr), phosphine, methyl chloroform (MC), ethylene dichloride (EDC) and chlorobromomethane, and of mixtures of MeBr and MC, EDC and MC, and phosphine and MeBr, to diapausing larvae of the pest was examined at 15, 20 or 25°C. At 15 and 20°C the tolerance of larvae was high and very high dosages of MeBr or liquid fumigants, or long exposures to phosphine, were required for total kill. At 25°C larvae were more susceptible to phosphine but retained a high tolerance of other fumigants. A mixture of 2% MeBr in MC showed evidence of potentiation at 25°C and achieved control of larvae at moderate dosages.
Fumigation of gypsophila flowers against Liriomyza trifolii1
Authors: CARMI Y.
Published: April 2008

Gypsophila cut flowers were fumigated with methyl bromide against Liriomyza trifolii. Complete control was obtained at a dose of 40 g/m3 methyl bromide, for 3 h at 15–18°C. To get satisfactory results without injuring the flowers they had to be conditioned at the above temperature for 6 h prior to fumigation.
In‐transit control of Liriomyza trifolii in chrysanthemum cuttings1
Authors: MORTIMER E. A. , POWELL D. F.
Published: April 2008

Individual cuttings and leaves of chrysanthemum infested with eggs and larvae of the alien leaf miner Liriomyza trifolii (Burgess) and batches of pupae, were treated in the laboratory in order to find an effective quarantine treatment to control the pest in imported cuttings. Cold treatment for 2 days at 1–2°C followed by methyl bromide fumigation at 15°C with a range of concentration time products (CTPs) was used to obtain accurate dose‐response lines and estimate the LD99 and LD99.9 for each stage of the insect. The largest estimates of the LD99 for eggs, larvae and pupae up to 3 days old were less than the CTP specified in the existing (as at September 1983) United Kingdom statutory fumigation treatment designed to prevent the entry of Spodoptera littoralis (Boisd.). This statutory schedule for unrooted cuttings consists of cold storage for 2 days at 1–2°C and then fumigation with methyl bromide at a CTP of not less than 54 g·h/m3 with a minimum treatment period of 4 h at a minimum air temperature of 15°C. Our results indicate that the Spodoptera treatment should give high levels of kill for most stages of L. trifolii provided a CTP of 54 g·h/m3 and a temperature of 15°C (throughout the fumigation) arc achieved uniformly within packs of cuttings when they are fumigated in their transit boxes in commercial practice. The practicality of the technique will depend on whether it is possible to achieve this without causing unacceptable phytotoxicity. The LD99 values for pupae more than 3 days old were greater than those for eggs, larvae and young pupae. Therefore, if this treatment were adopted as a quarantine measure against L. trifolii, good prophylactic treatments and rigorous prc‐packing inspections in exporting countries would still need to be maintained, to minimize any risk of importing pupae. The results are presented in full by Mortimer E.A. & Powell, D.F. (1984). Development of a combined cold storage and methyl bromide fumigation treatment to control the American serpentine leaf miner Liriomyza trifolii (Diptera: Agromyzidae) in imported chrysanthemum cuttings. Annals of Applied Biology105, (3), 443–454.
Development of a fumigation treatment of oak logs against Ceratocystis fagacearum1
Authors: LIESE W. , RUETZE M.
Published: April 2008

European veneer manufacturers depend greatly on oak imports from the USA. To prevent the accidental introduction of the American oak wilt disease (Ceratocystis fagacearum) into the member states of the European Community, a disinfection treatment was developed for oak logs with respect to the special demands of the veneer industry. Laboratory experiments and field trials in Europe and the USA showed that the fungus can be eradicated from large oak logs with bark attached, by a fumigation with 240 g methyl bromide/m3 applied for 3 days at temperatures of 3°C or above.
New techniques in fumigation under development by DEGESCH1
Authors: SULLIVAN J. B.
Published: April 2008

The diminishing availability of fumigant compounds makes it essential to improve fumigation techniques if adequate pest control is to be maintained. Three approaches developed by DEGESCH are discussed. Phosphine fumigation is now possible in cold weather if magnesium phosphide rather than aluminium phosphide is used as the source. Gas recirculation (the J‐system) provides for much more rapid fumigation in large grain silos. Finally, techniques are being developed to allow material to be added to, or removed from, a store during fumigation without hazard to the applicator.
Activité comparée du bromure de méthyle vis‐à‐vis de divers microorganismes du sol et mode d'action1
Authors: CUANY A. , ARVIEU J. C. , BERGE J. B. , BONNET P.
Published: April 2008

Les résultats obtenus montrent que l'activité biocide du bromure de méthyle est correctement mesurée par le produit C1T (concentration du bromure de méthyle dissous en mmole 1−1 x temps d'exposition en heures des organismes au toxique), mesure qui convient spécialement aux traitements du sol, le gaz y étant présent en solution aqueuse. Les valeurs de C1T qui produisent un effet léthal varient selon les particularitiés morphologiques des organismes et la température pour des raisons de réactions biochimiques et de cinétiques d'échanges physico‐chimiques. Il existe de plus un seuil de concentration minimale en deçà duquel l'effet pesticide n'est plus perceptible. Dans nos conditions standardisées de mesure, il apparaît que l'effet nématicide et herbicide se manifeste pour des C1T semblables, alors que les champignons et surtout les bactéries sont plus résistants. Ainsi, les perturbations observées sur la flore bactérienne du cycle de l'azote à la suite d'un traitement ne sont généralement que temporaires. Il est prudent toutefois d'éviter les traitements à fortes doses.
A critical review of so‐called cold sterilization in the field of foods1
Authors: JORDY A.
Published: April 2008

The contamination of raw materials with microorganisms is a potential hazard to human health, especially if these materials are kept for a certain time under conditions that enhance microbial multiplication. Since the goods in question are by no means cheap bulk materials, but are highly ranked substances, the method of germ reduction by heat treatment is not suitable, and various so‐called cold sterilizations have to be used (chemical, irradiation). The article examines the value of these, and in particular how they are assessed. Until the sixties, it was mainly the microbicidal effect of these treatments that was judged; today, the emphasis is on the assessment of the secondary reactions of the agents with the treated commodity and in particular their residual toxicity. In the case of chemical treatments, toxicity is determined directly by application of overdoses. It should be stressed that this is not comparable with the indirect assessment of the toxicity of gamma irradiation, by feeding irradiated goods. Of the available chemosterilants, formaldehyde has great disadvantages in spite of its high volatility, because of its high protein factor and its delayed vaporization from surfaces, due to polymerization. Propylene oxide is less active, requiring higher concentrations, which in turn results in increased residues. Therefore, the agent of choice is still ethylene oxide, since it diffuses quickly and is highly reactive; selection of genetically resistant microorganisms is therefore not possible, as opposed to the case of gamma radiation.
Les traitements thermiques de désinfestation des céréales et des produits céréaliers: possibilité d'utilisation pratique et domaine d'application1
Authors: LESSARD F. FLEURAT
Published: April 2008

La désinsectisation des grains et des produits céréaliers par un choc thermique est un moyen simple de lutte curative qui peut être rapidement installé dans les entreprises agro‐alimentaires. L'étude d'un procédé de désinsectisation thermique du blé et de ses produits de mouture dans un lit fluidiséà haut rendement est présentée. Il est montré qu'avec un équipement de laboratoire, puis à l'échelle pilote, les lits fluidisés à haute température (60 à 180°C) sont efficaces pour détruire rapidement l'infestation apparente ou cachée sans élever la température du produit au‐dessus de 72°C et avec un refroidissement immédiat. Le choc thermique à des températures d'air n'excédant pas 120°C n'altère pas de façon significative l'ensemble des qualités technologiques des produits désinsectisés: blé tendre panifiable, blé dur et semoules. Le prix de revient global du traitement est comparable à celui d'une fumigation. Son usage systématique est possible sur une gamme de produits dérivés des céréales qui ne peuvent recevoir d'application avec un insecticide de contact.
Evolution and biogeography of cyst‐forming nematodes1
Authors: FERRIS V. R.
Published: April 2008

Phylogenetic systematics is based on genealogy, rather than overall similarity, and a cladogram constitutes a potentially falsifiable hypothesis that can bring a new perspective to our understanding of the distribution and biogeography of a group of organisms. Sufficient data now exist for phylogenetic analysis of the Heteroderidae. New data at new levels of analysis comprise potential falsifiers for existing schemes.
Species, subspecies, race and pathotype problems in nematodes1
Authors: STURHAN D.
Published: April 2008

By reference mainly to cyst nematodes, certain aspects concerning the species category and intraspecific categories are considered. Special attention is paid to the existence of cryptic or sibling species, the possibility of interspecific hybridization, the phenomenon of reduced reproductive compatibility of certain populations within a species and the loss of subspecies and race identity in mixtures. Both terms ‘biological or physiological race’ and ‘pathotype’ can be used to express differences in host specificity in nematology, entomology and plant pathology. A distinction is made between the two categories and differences among them are outlined in detail. Whereas ‘race’ is considered as a population concept, pathotypes are defined as virulence phenotypes. Races are genetically variable groups of related populations, while pathotypes are a priori‘artificial’ entities, established for practical reasons and characterized by constancy of their relevant characters.
Possibilités et limites de l'utilisation de la variabilité protéique dans la détermination des espèces et races de nématodes à kystes1
Authors: BERGÉ J. B. , DALMASSO A.
Published: April 2008

Cet article est une revue bibliographique des résultats obtenus dans l'étude des protéines et enzymes des genres Heterodera et Globodera. Ces travaux ont permis de mettre en évidence une variabilité inter et intraspécifique. L'utilisation de ces caractères, comme outil taxonomique, ne sera optimisée qu'à condition de pousser aussi loin que possible l'analyse génétique de ces phénotypes. De plus, si l'on veut caractériser des entités subspécifiques (pathotypes), par les protéines ou enzymes, il est nécessaire de travailler sur des protéines liées à la fonction pathologique.
Modelling multigenic resistance to potato cyst nematodes
Authors: JONES F. G. W.
Published: April 2008

After making simplifying assumptions, the ability of female potato cyst nematodes to develop and reproduce is modelled by expressions of the type ix·x and ix·(1 ‐ x), where x is the frequency within a population of females able to circumvent the effects of a real resistance gene. Such females are potentially able to develop to maturity and reproduce to maximum capacity. For this class of females ix= 1, i.e. they are unaffected by the resistance gene. The frequency of other classes of females is given by (1 ‐ x) and for them ix ranges in value from just less than 1 to 0 according to the effectiveness of the gene. When ix approaches 0, females in these classes are eliminated and the gene responsible is said to be a ‘major’ resistance gene. For values of ix greater than 0, the genes responsible are called ‘minor’ genes. If full reproductive power is 1, then the total reproductive power in the presence of the resistance gene is [x+ix(1 ‐ x)] or when several genes are present by [x+ix(1 ‐ x)]·[y+iy(1 ‐ y)]·[z+iz(1 ‐ z)] etc. That is, the effects of these genes depend on the frequencies of females able to reproduce in their presence and on the effectiveness of the different genes as measured by i. Furthermore, ‘major’ and ‘minor’ genes are part of a continuum described by i. The model is used to illustrate the effects of combining ‘major’ and ‘minor’ genes and the effects of some arbitrary combinations are calculated. Data with which to test the model are sparse but what little there is tends to support it. Interactions between resistance genes, the fitness of females, the selection of males and the effects of resistant cultivars on populations are discussed. Selection by resistant potato hybrids in pots is surprisingly rapid and sometimes becomes evident after only five generations. Ways in which resistant cultivars might be used to prolong the useful life of resistant cultivars are briefly discussed.
Testing potato clones for resistance to Globodera rostochiensis (Ro1) and Globodera pallida (Pa2 and Pa3) by root‐ball screening1
Authors: HANSEN L. M.
Published: April 2008

Clones from the international test assortment were tested for resistance to Globodera pallida (Pa2 and Pa3) and estimated by root‐ball counting and by extraction of the total number of cysts to show the practicability of the root‐ball test. New clones in a breeding programme were tested by root‐ball counting for resistance to Globodera rostochiensis (Ro1) and G. pallida (Pa2 and Pa3), and the statistical aspects are discussed. The conclusion is that testing new clones early in a breeding programme by root‐ball counting of cysts with four to five replicates is a sufficient method to separate the susceptible clones from resistant and moderately resistant ones.
Morphological—taxonomical studies and pathotype classification in potato cyst nematodes1
Authors: OLSSON E.
Published: April 2008

Tests on differential clones for pathotype determination of potato cyst nematode populations were supplemented with morphological studies of male spicules. Such studies often speed up the process and are sometimes necessary for a proper pathotype identification.
Fungicide resistance: definitions and use of terms
Authors: DELP C. J. , DEKKER J.
Published: April 2008

On the basis of an analysis of current use of terms concerning resistance to fungicides, a series of definitions is proposed for discussion. Consistent use of such terms in scientific publications will facilitate understanding and avoid possible misinterpretations.
The fungicide resistance problem: will it grow worse?1
Authors: DEKKER J.
Published: April 2008

Failure of plant disease control due to development of resistance in fungi has become one of the major problems in chemical control. It is very important to prolong the use of a resistance‐prone fungicide by development of strategies to counteract resistance development. Various aspects are discussed, which are relevant to reaching this goal and in preventing the fungicide resistance problem from growing worse.
Résistance de Botrytis cinerea aux benzimidazoles et aux dicarboximides dans le vignoble français: conséquences pratiques1
Authors: LEROUX P. , BESSELAT B.
Published: April 2008

Des souches de Botrytis cinerea, agent de la pourriture grise de la vigne, résistantes aux benzimidazoles et/ou aux dicarboximides sont présentes dans de nombreux vignobles français et peuvent être à l'origine de réductions d'efficacité de ces fongicides. Une méthode basée sur l'action de ces produits au niveau de la germination des spores ou de l'élongation des filaments germinatifs permet d'analyser la composition de la population de B. cinerea au sein d'une parcelle donnée. La prospection réalisée chaque année dans les vignobles français á l'aide de cette technique permet de réaliser des préconisations régionalisées de lutte anti‐botrytis la saison suivante.
Resistance of Botrytis cinerea to benzimidazoles and dicarboximides: present situation on grapevine in Italy1
Authors: GULLINO M. L. , GARIBALDI A.
Published: April 2008

Resistance of Botrytis cinerea to benzimidazoles is present in Italy in almost all vineyards monitored, while resistance to dicarboximides has been detected in 36, 27 and 49% of tested vineyards during 1981, 1982 and 1983, respectively. In 1981 less than 1% of tested bunches carried dicarboximide‐resistant conidia. This value increased slowly with time: in 1983 4.9% of the tested bunches carried dicarboximide‐resistant conidia. Furthermore, only a low percentage (< 10%) of the conidia obtained from each bunch were resistant. Therefore, the present situation of resistance to dicarboximides on grapevine in Italy is certainly not serious and differs from that reported in other countries or on other crops. As a consequence, dicarboximides are still performing well, even in vineyards where resistance has been detected at a low level. No failure of grey mould control has been reported on grapevine in Italy up to now.
Effect of chlorothalonil on resistance of Botrytis cinerea to dicarboximides in cucumber glasshouses1
Authors: KATAN T. , OVADIA S.
Published: April 2008

Failures to control grey mould by dicarboximides on winter‐grown cucumbers in glasshouses in Israel were attributed to the development of resistance to these fungicides in populations of Botrytis cinerea. A survey of 18 glasshouses in the winter of 1983‐84 revealed that resistance is widespread where dicarboximides have been used extensively. During the summer, resistant B. cinerea populations often shift back to sensitivity; however, following few dicarboximide sprays in the subsequent winter, resistant strains reappear, increase rapidly and become dominant in the pathogen population. In two out of three glasshouse experiments, combination of chlorothalonil and dicarboximides in spray programmes slowed down the increase of resistant strains, whereas in a third experiment such a programme had no effect. The usefulness of chlorothalonil in fungicide‐alternation programme to suppress dicarboximide resistance is dicussed in relation to the fitness properties of established versus newly‐appearing resistant mutants.
Resistance to acylalanines in Phytophthora infestans in The Netherlands1
Authors: DAVIDSE L. C.
Published: April 2008

In The Netherlands in 1980 a severe late‐blight epidemic involving metalaxyl‐resistant strains of Phytophthora infestans did considerable damage to the potato crop. As a consequence metalaxyl or metalaxyl‐containing products were withdrawn from the Dutch fungicide market for the control of potato late blight. In 1981 the majority of the P. infestans isolates obtained from various parts of the country were sensitive to metalaxyl. In three areas where metalaxyl mixtures were used on a relatively large scale metalaxyl‐resistant strains dominated the population. Incidental use of metalaxyl mixtures in 1982 and 1983 showed adequate late‐blight control and, when in 1984 an early and in some areas severe epidemic developed, a metalaxyl/mancozeb mixture was reintroduced for curative application in combination with conventional fungicides. Although disease control was adequate, resistant strains were present in a small number of fields. Whether resistant strains will increase in frequency and threaten the usefulness of mixtures of acylalanines will heavily depend on how well potato farmers adopt strategies involving a limited use of mixtures of acylalanines in a spray schedule with conventional late‐blight fungicides.
Resistance to acylalanines in Pseudoperonospora cubensis1
Authors: PAPPAS A. C.
Published: April 2008

Resistance to acylalanine fungicides in Pseudoperonospora cubensis, the downy mildew of cucurbits, is reviewed. Insensitive strains of the fungus predominated during the second year of metalaxyl application in cucumber glasshouses in Greece and Israel. Resistance was detected either on detached cucumber leaves floated on metalaxyl solutions or on potted plants treated (sprayed or drenched) with this fungicide. Metalaxyl‐resistant strains of P. cubensis showed good pathogenicity and fitness, and competed favorably with the sensitive strains in the absence of the fungicide. A synergism between these two biotypes resulted in an increased virulence of the resistant forms on metalaxyl‐treated plants. Metalaxyl‐resistant strains of the pathogen exhibited cross resistance to other acylalanine fungicides. Strains resistant to acylalanines and to the chemically unrelated oomycete‐fungicides fosetyl‐Al and propamocarb were isolated in Israel, as well. In Greece, however, protective sprays with fosetyl‐Al, cymoxanil and mancozeb gave good control of cucumber downy mildew when the pathogen was resistant to metalaxyl. P. cubensis is the first case of fungus which developed resistance to acylalanines in the field.
Occurrence of metalaxyl‐resistant isolates of Pseudoperonospora cubensis in Israel: a 5‐year survey1
Authors: SAMOUCHA Y. , COHEN Y.
Published: April 2008

The occurrence of metalaxyl‐resistant isolates of Pseudoperonospora cubensis, the causal agent of downy mildew in cucurbits, was surveyed during 1980–1984 subsequent to their first appearance in December 1979. Metalaxyl use was abandoned in mid‐1981 and resistant isolates diminished in late 1981. Metalaxyl use was renewed in 1982 and a gradual increase in frequency of resistant (R) strains was detected. In 1983, 31 out of 40, and in 1984, 43 out of 47 isolates tested were highly resistant to the fungicide with 65 and 91% of them, respectively, collected from plastic houses or fields not treated with metalaxyl. The survey indicates a rapid build‐up of R strains of the fungus and the need for alternative chemicals for combating downy mildew in cucurbits.
Méthode d'évaluation du taux de souches résistantes aux anilides dans une population de Plasmopara viticola: application à la surveillance du vignoble en France1
Authors: CLERJEAU M. , MOREAU C. , PIGANEAU B.
Published: April 2008

Depuis la mise en évidence en 1981 de souches résistantes aux anilides chez Plasmopara viticola, la surveillance (‘monitoring’) du vignoble français est une nécessité pour adapter les prescriptions de lutte contre le mildiou à la nature des populations du parasite. Les tests d'inoculation sur disques de feuilles de vigne placés ou non en présence de métalaxyl sont bien adaptés aux besoins de cette surveillance. Utilisés à des fins de détection qualitative des souches résistantes (présence ou absence), ces tests ne présentent cependant qu'un intérêt partiel. Les données issues de contaminations artificielles par des populations contenant des proportions connues de souches résistantes (R) nous permettent de proposer une méthode d'évaluation quantitative. Cette méthode d'estimation permet de suivre l'évolution du taux de souches résistantes dans le temps ou dans l'espace et d'émettre des hypothèses sur les exigences écologiques comparées des souches sensibles et résistantes ou sur l'influence des stratégies de traitements sur la dynamique de ees souches. L'organisation du ‘monitoring’ en France est présentée.
Haustorial development test to characterize metalaxyl resistance and genetic variability in Plasmopara viticola1
Authors: HERZOG J. , SCHÜEPP H.
Published: April 2008

A new method is described for assessing haustorium formation in Plasmopara viticola on metalaxyl‐treated grape leaves. Using this method, three types of sensitivity of P. viticola to metalaxyl could be distinguished and the precise ratio of sensitive, ‘reduced sensitive’ and resistant zoospores of selected isolates could be determined.
Efficacité du phoséthyl‐Al contre les souches de Plasmopara viticola résistantes aux anilides (acylalanines)1
Authors: GAULLIARD J. M.
Published: April 2008

Onze souches de Plasmopara viticola ont étè prélevées en diverses régions de France (Charentes, Beaujolais, Touraine) sur des parcelles ou les traitements avec des fongicides de la famille des anilides avaient manqué d'efficacité. Elles ont été mises en culture sur vignes en serre. Dix d'entre elles ont manifesté une forte résistance aux anilides; par contre, toutes se sont montrées sensibles à une application de phoséthyl‐Al. Le phoséthly‐Al conserve done son activité sur les souches de mildiou de la vigne devenues résistantes aux anilides.
Benzimidazole resistance in Pseudocercosporella herpotrichoides: results of ADAS random surveys and fungicide trials in England and Wales, 1982–19841
Authors: GRIFFIN M. J. , KING J. E.
Published: April 2008

Surveys of 59 and 528 randomly selected winter wheat and winter barley crops in 1982 and 1983 respectively, showed that benzimidazole‐resistant strains of the eyespot fungus (Pseudocercosporella herpotrichoides) were common and widespread. The frequency of occurrence of resistant isolates, both in 1982 and 1983. was positively correlated with the number of benzimidazole fungicide applications since 1975. Resistance was much more frequent in R‐type than in W‐type strains of P. herpotrichoides. Fungicides or fungicide mixtures, applied to winter wheat at growth stage (GS) 31, were compared for control of eyespot at six sites in 1983 and one in 1984 where benzimidazole‐resistant strains were readily detected prior to spraying. Carbendazim alone gave no control of eyespot and in some trials actually increased disease levels compared with the unsprayed control. Prochloraz, either alone or in mixture with carbendazim, was the most effective fungicide giving a moderate control of eyespot (33–42% reduction) and cost‐effective yield increases. DPX‐II6573, tested only in the 1984 trial, was as effective as prochloraz. The practical implications of these findings are discussed.
Two different processes for the selection of fungicide‐resistant sub‐populations1
Authors: SKYLAKAKIS G.
Published: April 2008

Plant pathogen populations subjected to selection for fungicide resistance have responded either qualitatively through the establishment of a new highly resistant population or quantitatively through a gradual loss of sensitivity. The type of response seems to be dictated by the toxicant rather than by the target organism. The qualitative response is better understood, proceeds faster, and leads usually to a sudden and complete loss of disease control in the field. The quantitative response is less well understood, proceeds slower, and loss of disease control associated with it is gradual and frequently incomplete. It seems that the same strategies, fungicide mixtures and alternations, can be used to delay both responses; however, substantially more direct experimental evidence is needed to support and better quantify the effects of these strategies.
The resistance strategy for acylalanine fungicides1
Authors: URECH P. A. , STAUB T.
Published: April 2008

Since the commercial introduction of metalaxyl and the outbreaks of resistance that followed soon thereafter, a number of new acylalaninc‐type fungicides have been developed which have or will shortly come onto the market. Based on the understanding that anti‐resistance strategies can only be effective if they are followed by all manufacturers, there has been considerable effort over the past few years to coordinate anti‐resistance strategies among the companies involved. The most important of these is that acylalanine fungicides will only be available in prepacked mixtures with residual contact fungicides so that the use of the single product is excluded. At the same time only two to four applications per season arc recommended and no curative use of the products. In order to ensure the success of such restrictions, it is necessary that their need should be recognized and their enforcement supported by extension and advisory bodies.
Strategies to prevent build‐up of resistance to fungicides in cereal crops in Switzerland1
Authors: GINDRAT D. , FORRER H. R.
Published: April 2008

The use of fungicides in wheat and barley production has increased impressively during the last 10 years in Switzerland. Although no resistance to fungicides has yet been recorded in the field, strategies to delay resistance build‐up have been developed. They are the result of collaboration between official research and advisory services. More co‐operation is desirable, however, between officials and chemical companies at the level of farmer advice. Our recommendations are based on the following points: 1) minimal numbers of applications; 2) whenever possible, fungicides with multisite action should be used; 3) all components of a mixture should aim at pathogens present to a significant extent in the crop; 4) long‐term, flexible strategies. Implementation of these strategies is made easier by several methods for deciding when and whether to treat (EPIPRE; risk evaluation; disease threshold levels). We recommend the alternation of single‐site compounds according to their mode of action, rather than the use of mixtures (multi‐ + single‐site, or single‐site). A major reason is the common, simultaneous occurrence of a variety of pathogens in cereal crops. Preferring a ‘mixture strategy’ to alternation would imply the use of cocktails of several compounds with possible major disadvantages such as cost, residues, and iatrogenic diseases.
Aims and activities of industry's fungicide resistance action committee (FRAC)1
Authors: WADE M. , DELP C. J.
Published: April 2008

FRAC is a GIFAP‐sponsored inter‐company committee dedicated to prolonging the effectiveness of fungicides liable to encounter resistance problems and to limit crop damage during the emergence of resistance. Through FRAC and the Working Groups it co‐ordinates, companies are striving to establish more effective communications to alert all people involved in the research, production, marketing, registration and use of fungicides to the problems of resistance. With an enlightened attitude, effective strategies can be conceived and adopted. Co‐operative action is deemed essential if the invaluable option of chemical disease control for crops is to be preserved. Working Groups for acylalanines, benzimidazoles, dicarboximides and sterol inhibitors are well organized and functioning in various monitoring studies and cooperative actions. FRAC meets regularly to review the activities of the Working Groups and to deal with the wider aspects of fungicide resistance. FRAC initiates, stimulates and monitors Working Groups, provides guidelines and co‐ordinates the efforts of the Working Groups, helps Working Groups communicate their conclusions, publicises guidelines on procedures/definitions of practical resistance research, provides technical counsel for fungicide‐resistance courses and research studies, and liaises with universities, advisers, farmers, distributors, governments.
Citrus certification in Mediterranean countries1
Authors: NAVARRO L.
Published: April 2008

Citrus suffers severe losses from virus and similar diseases, which are mainly spread by grafts, stocks and scions. This planting material needs to be made virus‐free throughout the Mediterreanean region. The standards published by EPPO in 1980 remain valid for this purpose: they provide techniques for elimination of the viruses and for protecting healthy material from reinfection. The actual situation in individual Mediterranean countries is reviewed, especially with regard to certification programmes (still not started in several cases). Healthy planting material of certain cultivars can be obtained on the international market, but this is not true of local cultivars which also need to be certified. In any case, the import of planting material carries the risk of introducing diseases not yet present in the Mediterranean region, so that strict quarantine procedures are needed.
Programme d'amélioration sanitaire et de certification des agrumes au Maroc1
Authors: NADORI E. B. , NHAMI A. , TOURKMANI M.
Published: April 2008

Le verger agrumicole du Maroc est en général fortement contaminé par les virus, viroïdes et mycoplasmes. La sélection sanitaire par indexage, la sélection nucellaire et la régénération sanitaire par microgreffage d'apex permettent actuellement d'obtenir un matériel sain pour les principaux cultivars, qui servira de base à la production de plants d'agrumes certifiés dans des pépinières controlées et soumises à un règlement technique officiel.
Maladies de l'eucalyptus1
Authors: LANIER L.
Published: April 2008

Les eucalyptus constituent—au moins au meme titre que les genres Pinus et Populus—l'un des genres d'arbres forestiers les plus importants à l'échelle mondiale, et en particulier par l'extension considérable des reboisements (plus de 4 millions d'ha) en régions tropicales, sahéliennes et tempérées chaudes. L'article tente de faire le point sur les problèmes posés par les maladies pouvant gener cet effort de reboisement, notamment en région méditerranéenne, et souligne l'importance et l'avenir des eucalyptus dans cette région. Il est procédéà un inventaire général, à l'échelle mondiale, des maladies des eucalyptus et de l'importance des parasites en cause. Un certain nombre d'entre eux sont étudiés plus en détail, selon qu'ils sont présents dans le pays d'origine des eucalyptus ou dans les zones où ils ont été introduits. Une section est réservée à la région méditerranéenne, où certaines maladies s'en prenant aux racines, aux rameaux, aux feuilles ou au bois ont été identifiées; pour l'instant, la plupart d'entre elles ne sont pas trop graves. Enfin, des propositions et des règles de protection phytosanitaire, visant à restreindre les risques d'introduction des parasites les plus dangereux ou d'extension de ceux existant actuellement, sont citées, en insistant sur les risques de transport de maladies d'une région à une autre par l'intermédiaire des échanges de matériel végétal autres que les graines.
Importance des insectes ravageurs de l'eucalyptus en région méditerranéenne1
Authors: CADAHIA D.
Published: April 2008

Ce travail résume la situation phytosanitaire du genre Eucalyptus en se référant aux insectes ravageurs qui mettent en danger les plantations artificielles dans le monde et plus particulièrement dans le bassin Méditerranéen. Parmi les 54 espèces citées, 10 ont dépassé les frontières de leur aire d'origine et, parmi ces derniers, 6 se trouvent sur d'autres continents et 3 dans la région méditerranéenne. Il est fait état aussi des mesures phytosanitaires touchant à la quarantaine, mises en place pour l'Eucalyptusà l'initiative de l'OEPP. Les ravages causés par les insectes polyphages dans la région méditerranéenne sont récapitulés. Les 3 insectes mentionnés sont spécifiquement inféodés au genre Eucalyptus et causent des dégats en région méditerranéenne. La présente étude s'y attache en précisant leur extension et les moyens de lutte susceptibles d'etre mis en oeuvre. En ce qui concerne Ctenarytaina eucalypti quia atteint nos régions durant les années soixante, on assiste à son extension, mais l'action des syrphides prédateurs parvient à en contenir les populations. Quant àGonipterus scutellatus apparu en région méditerranéenne vers 1975, il n'a pas connu l'extension à laquelle on pouvait s'attendre en tenant compte de son potentiel de dispersion élevé. L'espèce demeure peu préoccupante, mais doit faire l'objet d'attention surtout sur les eucalyptus ornementaux où les dégats peuvent etre sensibles. Elle se rencontre sur la Riviera italienne et dans le Midi de la France où ses populations sont controlées par le parasite oophage Patasson nitens. Au cours des dernières années, le ravageur le plus redoutable est certainement Phoracantha semipunctata qui s'est répandu dans la partie occidentale du bassin Méditerranéen. En ce moment, seules la France, la Yougoslavie et la Grèce sont demeurées indemnes. Cette diffusion rapide est à mettre en rapport avec l'état d'extreme déficience des arbres, essentiellement du à la sécheresse et à la pauvreté des sols. La stratégie de lutte menée en Italie s'est révéléc efficace; elle consiste à intervenir dès le début de l'attaque des peuplements en pratiquant des coupes et en utilisant rapidement le bois affecté. De cette facon, l'importance des populations s'est vue considérablement réduite. D'une facon générale, les racines ont donné des repousses vigoureuses sauf dans les cas où les coupes ont été faites tardivement. L'expérience espagnole de lutte par des arbres‐pièges sur de vastes étendues est également très intéressante. Par ce moyen il a été possible d'observer une réduction moyenne des populations de 75% avec une rentabilité de 246–611%.
Influence of plastic mulching and disinfection on the fungal flora of soils in Belgium1
Authors: WELVAERT W. , POPPE J.
Published: April 2008

Plastic mulching was tested in Belgium over several years as a method for modifying the population of pathogens and saprophytic fungi in the soil, both in the glasshouse and in the field. The plastic film was kept on the soil for 3 or 6 months, and treatments with formaldehyde, methyl bromide or dazomet were also applied. In the glasshouse the fungal flora was decreased after 6 months’plastic cover without disinfectants, especially for Mucor and Rhizoctonia, but Trichoderma was favoured. The plastic layer together with formaldehyde resulted in 50% killing of soil fungi. In the field with plastic layer only, there was a slight decrease in some fungi and an average increase in bacteria. With plastic combined with formaldehyde (250 ml m‐2), methyl bromide (100 gm‐2) or dazomet (80 g m‐2), better results were obtained. Fungi were reduced 75% with formaldehyde and 80–100% with methyl bromide or dazomet depending on soil depth. Qualitatively there was a clear shift towards Trichoderma, while pathogenic fungi such as Verticillium and Fusarium were nearly 100% killed.
Control of Verticillium dahliae on tomato in Tunisia by resistant cultivars and soil disinfestation1
Authors: MOENS M. , AICHA B. BEN
Published: April 2008

Verticillium dahliae is an important soil‐borne pathogen of vegetables in the central coastal region of Tunisia. Cultivation of resistant tomato cultivars does not always give satisfaction as they do not fulfil agronomic requirements (earliness, fruit size and yield). Soil treatment with dichloropropene/methyl isothiocyanate mixture (36.12 g + 16.45 g m‐2) gave excellent control of verticillium wilt and nearly tripled the yield of the susceptible cultivar H63–5. Dazomet (60 g m‐2) caused only slight disease depression and less yield increase.

Parmi les pathogènes édaphiques des cultures maraîchères, Verticillium dahliae occupe une place importante dans le Sahel tunisien. Bien que les cultivars résistants donnent entière satisfaction sur le plan phytopathologique, leur utilisation est limitée à cause de leurs faiblesses agronomiques (précocité, calibre des fruits et rendement). La désinfection du sol avec le mélange dichloropropène/méthyl‐isothiocyanate (36, 12 g + 16,45 g m‐2) réduit considérablement la verticilliose et triple presque le rendement de l'hybride sensible H63‐5. L'incidence du dazomet (60 g m‐2) sur la trachéomycose et le rendement était moindre.
Techniques of applying nematicides to soil1
Authors: WHITEHEAD A. G.
Published: April 2008

Methods of applying currently available fumigant and non‐fumigant nematicides to soil are briefly discussed. These are: seed, seed furrow, crop row, seedbed, planting hole, localised topsoil and topsoil treatments. The choice of treatment depends on many factors including the pest to be controlled and the value of the crop. The Vertical Band‐Rotary Harrow technique can be used for seed furrow, wide band and topsoil treatment and has advantages over conventional techniques.