bluuebunny/crossref_metadata_2025 huggingface dataset:
Recent Developments in Pesticide Application by the United States Animal and Plant Health Inspection Service1
Authors: WILLIAMSON R.L. , WOOD J.R.
Published: April 2008

Aerial application of pesticides is generally the method used by the United States Department of Agriculture (USDA) in the control of pests of rangeland, cultivated crops, and forested areas. With increased restrictions placed on pesticides, then‐ continued use requires improved application technology to meet acceptable levels of risk at reasonable cost The Animal and Plant Health Inspection Service of USDA is developing an aerial spray drift model for use by their field personnel to minimize drift from aerial application of pesticides to environmentally sensitive areas. Input information utilizing a low cost, field‐deployable microcomputer includes aircraft type, application technique and hardware, pesticide formulation, meteorological conditions, and type (roughness) and extent of the site. Expected output computations will be: 1) distribution pattern of downwind deposition, including evaporation corrections and matching to empirical field measurement; 2) optimal aircraft swath spacing; and 3) buffer distance between the target area and the environmentally sensitive areas.
Electrostatic Application with Rotary Atomisers1
Authors: ARNOLD A.J.
Published: April 2008

The APE80 charged rotary atomiser, and its larger, JUMBO, counterpart, both developed at Rothamsted, are briefly described. Recent design modifications allow control of the trajectory and subsequent distribution of the spray. Some field results illustrate the increase in deposition obtained with charged sprays and the effect on spray penetration.
New Experience with Formulations for ULV Application1
Authors: KEIM F.D.
Published: April 2008

For economical and environmental reasons, new application methods and formulations of pesticides are continually being tested. Amongst the application methods, aerial ULV spraying is becoming more and more important. There are two main fields for aerial ULV application: crop and non‐crop spraying. Non‐crop spraying is widely used for locust, mosquito and tsetse control. ULV formulations used for these purposes must be specially designed due to the extraordinary conditions in which they are applied. The choice of solvent, which should have a certain dissolving power, will determine the viscosity, volatility and phytotoxicity of the formulation. Because the positive and negative physical properties of the available solvents are sometimes inversely related, a suitable formulation is always a compromise. As an example, the physical properties of two endosulfan ULV formulations for crop spraying and non‐crop spraying (tsetse control) are discussed.
Some Aspects of New Technology for Protection of Field Crops in Poland (Machinery and Techniques)1
Authors: WACHOWIAK M.
Published: April 2008

The Institute for Plant Protection at Poznan (Poland) examines the biological efficacy of new plant protection equipment or techniques. Examples of recent studies include: 1) a sprayer with a lateral reach of up to 40 m under favourable conditions, which has been successfully used on crops liable to mechanical damage from traditional tractor sprayers (oilseed rape at flowering, field bean, seed crops of sugar beet and onion, sunflower, maize); 2)equipment for spraying potatoes against Thanatephorus cucumeris at the time of planting; 3) use of passage‐ways for sprayers in cereal crops, results having shown that spraying from passage‐ways gives better biological results and that adjoining plants compensate the losses due to absence of plants in the passage‐ways.
Evaluation of Novel Pesticide Application Techniques1
Authors: MATTHEWS G.A.
Published: April 2008

Most new pesticides are assessed in the laboratory and field assuming commercial application in sprays diluted to around 2001/na or more. Relatively few products are registered for ULV/CDA (ultra‐low volume/controlled droplet application) sprays. Methodology for comparative assessment of novel application techniques is considered.
Criteria for Choosing Application Techniques for Desert Locust Control1
Authors: COURSHEE R.J.
Published: April 2008

Insecticides may be applied in several ways to control desert locusts. The traditional method, of feeding poisoned bait to hopper bands, uses insecticide very efficiently and is inexpensive when put into practice on a limited scale. However, it is both expensive and ineffective when a plague arises. Treating individual bands with contact insecticides is similar and suitable for operations on a modest scale in countries where much of the land is developed for agriculture. Two large‐scale methods, matching the size of a locust plague occurring in uncultivated deserts, are the treatment of swarms of adults and spraying dieldrin onto the natural vegetation of the breeding sites. Despite the small dose rate of dieldrin needed ‐ tens of grams per hectare ‐ the last method is very expensive when breeding occurs over the large areas which are susceptible ‐ hundreds of thousands of square kilometres. Although all methods are suitable and used for particular circumstances, the last alone is the only one of general value and practical feasibility that can match the dimensions of a locust plague. Despite its high cost and the use of small dose rates of a persistent organochloride insecticide, the analysis of benefits and costs indicates that it will be the method mostly used in deserts, if a plague occurs again. The arguments leading to this conclusion are presented to illustrate an example of the type of study required to decide how to apply pesticides in practice for more familiar pest management tasks.
Trends and Costs in the Development and Testing of Plant Protection Machinery1
Authors: DIMITRIEVITS G.
Published: April 2008

New developments in plant protection technique give rise to new requirements in the development of spray equipment, which must then be tested for its efficiency, uniformity and optimum performance in relation to output and droplet characteristics. The problems in doing this are illustrated by the results of a trial on orchard spraying in Hungary. The need to relate performance to biological requirements is particularly stressed.
The Extraction and Diagnosis of Corynebacterium sepedonicum from Diseased Potato Tubers1
Authors: DINESEN I. G.
Published: April 2008

Corynebacterium sepedonicum causes a very severe disease in potato and it is therefore necessary for the method of its diagnosis to be specific and for the extraction technique to ensure that even small amounts of bacteria will be found. By using indirect immunofluorescence staining it was possible to get a reliable diagnosis. For this purpose a specific serum was produced. To find the best technique for extracting the bacteria from potato tubers, two methods were compared. One was based on maceration of the plant material in a Waring blender followed by centrifugation. Immunofluorescence staining was done on the resuspended sediment. The other method was carried out by cutting the potatoes into small pieces (about 1 cm3) and transfering them to a bottle containing sterile water. The bottle was shaken for 3 or 16 h and samples for immunofluorescence tests were taken from the fluid. Centrifugation could be used if necessary before immunofluorescence staining. The results show that the most reliable technique for extraction was to shake the plant material for 16 h followed by centrifugation. If there are heavy symptoms, dilution of the extracted material may be necessary.
Analyse économique concernant les mesures de quarantaine prises à I'égard de Phorecantha semipunctate en Espagne1
Authors: Cicuéndez D. Cadahia
Published: April 2008

L'introduction en Espagne et au Portugal de Phoracantha semipunctata a causé dinnombrables problèames, bien que ce ravageur provoque moins de dégits dans les cultures d'eucalyptus bénéficiant de conditions favorables. Afin de protéger la zone atlantique de l'Espagne demeuré indemne, l'importation de bois d'eucalyptus à partir du Portugal a été d'abord suspendue, puis soumise à de nouvelles exigences phytosanitaires (stockage du bois écorcé pendant 3–6 mois). De même, le transport de bois d'eucalyptus vers la région atlantique a été interdit. Le coût annuel des mesures de quarantaine interne s'élève à environ 22.500.000 pesetas, alors que la quarantaine extérieure représente pour le Portugal 60.000.000 pesetas de frais supplémentaires et que l'Espagne dépense 5.000.000 pesetas en plus pour l'inspection. II n'est cependant pas possible d'estimer le bénéfice retiré par l'absence du ravageur dans la zone atlantique.
Bilan éonomique des mesures de lutte contre le feu bactérien dans le Sud‐Ouest de la France1
Authors: Thiault J.
Published: April 2008

Le feu bactérien est apparu dam le Sud‐Ouest de la France en 1978 dans une région où la culture du poirier est importante. De sévères mesures prophylactiques ont été prises (arrachages, taille, pulvérisations) pour limiter l'extension de la maladie. Pour la période 1979–1983 cet ensemble de mesures a coété 21.470.000 francs, ce qui représente 2,5 % du chiffre d'affaires des vergers de poiriers et pépinières de la région. Sans ces mesures, on estime que la maladie aurait détruit en 5 ans un capital de 185 millions de francs, entrainant une perte annuelle de 205 millions de francs de recettes et la disparition de 1500 emplois.
The « Green Corner »; a Pre‐export Inspection System for Chrysanthemum Cutflowers and Pot Plants in The Netherlands1
Authors: Veenenbos J.A.J.
Published: April 2008

Under the « green corner » export inspection system for chrysanthemum cut flowers and pot plants, an intensive pre‐export inspection is preceded by a registration and inspection system of the nursery and by an inspection and marking of the produce with a green sticker at the auction. This inspection system gives a high level of security that the produce is free from Liriomyza trifolii and Puccinia horiana. It is in operation to fulfil the stringent import requirements of some countries.
The Need for an International Approach for the Production of Virus‐free Propagation Material1
Authors: VAN DER Graaff N.A. , Chiarappa L.
Published: April 2008

Propagating material of fruit trees, citrus and grapevine moving in international trade has a substantial risk of being virus‐infected. Developing countries in particular need to be able to import high‐quality « virus‐free » material from reliable sources. Even if such material is obtained, its multiplication and distribution entail risks of reinfection, observed in practice on many occasions, unless careful supervision by trained staff can be ensured. In the Mediterranean Region and the Near East, FAO, in conjunction with EPPO, is working towards a scheme in which special institutes in individual countries (France, Italy, Spain …) cooperate in an inter‐country programme for production of virus‐free stock and for training in its use. The establishment of a Centre for the Improvement of Mediterranean Horticultural Crops at Valenzano, Bari (IT) is a major element of this scheme.
Plant Quarantine Facilities in The Netherlands1
Authors: Veenenbos J.A.J. , Treur A.
Published: April 2008

In The Netherlands germplasm and plants collected in the wild for breeding and scientific purposes may only be imported with a special licence. For this material specific post‐entry import requirements are prescribed. A glasshouse with special quarantine facilities has been built on the premises of the Plant Protection Service at Wageningen. In this paper the special facilities needed to carry out post‐entry quarantine are described.
Extent and Economics of Biological Control of Tetranychus urticae and Trialeurodes vaporariorum in Danish Glasshouses1
Authors: Hansen L.S. , Jakobsen J. , Reitzel J.
Published: April 2008

A survey was conducted among Danish tomato and cucumber growers concerning the use of biological and chemical control in Danish glasshouse crops in 1982. The survey revealed a widespread use of biological control of Tetranychus urticae and Trialeurodes vaporariorum on glasshouse crops of cucumber and tomato (87 and 77 % of the area, respectively). The growers estimated biological control to be cheaper than chemical control, and showed a pronounced preference for biological control (82 % of the replies). In cucumber crops, the area on which biological control was uninterrupted throughout the growing season was greater than in tomato crops, despite the fact that more chemical applications against other pests and diseases were necessary on cucumber crops. A list of the pesticides most commonly used in glasshouses in conjunction with successful biological control of spider mite is presented. Guidelines for biological and chemical control of spider mite on cucumber and whitefly on tomato are given.
La fumigation au bromure de méthyle dirigée contre le nématode des tiges, Ditylenchus dipsaci, contenu dans des lots de semences et de bulbes1
Authors: CAUBEL G. , DUCOM P. , MARRE R.
Published: April 2008

La semence contaminée représente un facteur de dissémination capital pour Ditylenchus dipsaci. La pratique de la fumigation au bromure de méthyle permet l'éradication des individus anabiotiques contenus dans les lots de semences. L'étude de plusieurs techniques au cours de diverses combinaisons de concentration (C) et de durée (T) montre que pour la fumigation de lots de luzerne l'éradication de D. dipsaci est atteinte, par exemple, à pression atmosphérique avec 80 g/m3 pendant 16 h (C x T théorique de 1280), ou après vide préalable avec 50 g/m3 pendant 20 h (C x T théorique de 1000). Si aucune altération de la faculté germinative n'est observée, même apres un delai de 2 ans après le traitement, on constate qu'un certain effet fongicide peut se révéler intéressant. Avec Vicia faba, les cssais préliminaires indiquent que pour cette espèce à grosse graine, le nématode est mieux protégé dans les cotylédons. La limite entre l'action nématicide et phytotoxique est restreinte; la technique du vide partiel pourrait présenter un intérêt. Pour l'ail, l'éradication de D. dipsaci est possible par la fumigation des têtes entières, mais un effet phytotoxique est à redouter au‐delà d'un produit C x T théorique de 800. Cette phytotoxicité, grave si la dormance de l'ail est levée, peut s'expliquer par une adsorption marquée. Il est néccssaire de poursuivre l'expérimentation en évaluant les risques présentés par d'éventuels résidus bromés dans les caïeux et en réétudiant l'utilisation de la phosphine, malgré son efficacité insuffisante lors de premiers essais.
Use of pheromone traps for the proper timing of fumigation in the storage environment1
Authors: LEVINSON H. Z. , LEVINSON A. R.
Published: April 2008

We have broadly divided the methods of storage insect manipulation into curative and preventive measures. Sex and aggregation pheromoncs combined with additional sensory stimuli in adhesive bait traps can be utilized as a preventive measure which may lead to insectistasis (a state wherein the insect population density is diminished to the extent of allowing storage without significant impairment). Insectistasis can be readily achieved by continual supervision of store rooms, use of adhesive bait traps in combination with a limited number of curative measures (e.g. gaseous or contact insecticides) timed according to the extent of trap catches. The sensory stimuli causing male storage moths (Phycitinae) to fly towards these bait traps involve, in sequence, a circadian rhythm, increasing or decreasing light (intensity approximately 1–10 Lux), an air current, a vertical rectangular figure and the main pheromone component. The antennae of male Anagasta kuehniella, Ephestia elutella and Plodia interpunctella comprise two types of receptor cells, of which one is selectively responsive to (Z,E)‐9,12‐tetradecadienyl acetate (TDA) and (Z)‐9‐tetradecenyl acetate (TA), while the other responds to (Z,E)‐9,12‐tetradecadien‐l‐ol (TDO).
Problems of development of resistance to phosphine by insect pests of stored grains1
Authors: DYTE C. E. , HALLIDAY D.
Published: April 2008

The FAO global survey of pesticide sensitivity of stored grain pests in 1972–73 showed an overall incidence of phosphine resistance of 9.7% in insect strains from 82 countries, especially in Tribolium spp. and Rhyzopertha dominica. The levels of resistance increased under laboratory selection. Generally, eggs and pupae were found to be more tolerant, and fumigation doses have to be designed with these stages in mind. With increasing worldwide use of phosphine, resistance has become more frequent and occurs at a higher level and in other species (Cryptolestes ferrugineus, Oryzaephilus surinamensis). Studies of fumigation under different conditions in Bangladesh showed that common procedures, without use of sheets, led to chronic underdosing, creating ideal conditions for the selection of resistant strains. Such strains are very likely to be introduced into the EPPO region and established there. While inspection and control procedures in ports could limit this risk, these are costly and impractical. The problem is best tackled at source, by supporting projects aimed at improving the conditions under which grain is stored and fumigated in developing countries.
Phosphine permeability of various plastic sheets and films1
Authors: WOHLGEMUTH R.
Published: April 2008

Effective phosphine fumigation depends on the maintenance of sufficiently gas‐tight conditions. The German Agency for Technical Cooperation (GTZ) has started a programme to ensure that suitable gas‐tight, mechanically resistant foils are available for developing countries. Six foils were tested for gas‐tightness under laboratory conditions before and after repeated twisting in a special apparatus. Much the best was Waloplast Combi, which was completely impermeable and not damaged by twisting, though its thinness makes it liable to splitting by sharp edges and it would be better combined with mechanically resistant materials. The other foils mostly gave similar moderately good gas‐tightness, but varied considerably in their susceptibility to damage.
A simple multiport valve and sampling technique for use in determining fumigant gas concentrations inside small enclosures1
Authors: POWELL D. F.
Published: April 2008

Single‐tube sampling systems may extract a significant proportion of the volume of gas in small enclosures, artificially increasing gas diffusion rates. A loop‐sampling system, which recirculates the gas through the enclosure, was designed to overcome this problem. A multiport sampling valve is described which allows a single thermal conductivity meter to be used with sampling loops to measure gas concentrations at up to three points in succession.
The control of mole, water vole and muskrat with phosphine1
Authors: JOBSEN J. A. , UILENREEF H. E.
Published: April 2008

The number of rodenticides for control of outdoor rodents and the number of uses of the remaining products is declining. Phosphine is valued highly because it causes no secondary poisoning and is considered to be environmentally safe. Although it has been used against mole (Talpa europaea) and water vole (Arvicola terrestris) in some countries for decades, in other countries a breakthrough is more recent. The development of a new formulation, generating phosphine rapidly, may also contribute to a wider use. In the Netherlands investigations have been undertaken on the mode of application against mole and water vole. Experiments against muskrats (Ondathra zibethicus) show promising results. The use of phosphine against this rodent could save on labour considerably, when compared to trapping.
Effets de la matière organique sur la bioactivité et la dégradation du bromure de méthyle dans le sol1
Authors: ARVIEU J. C. , CUANY A.
Published: April 2008

La matière organique des sols et des substrats de culture donne lieu à des interactions physico‐chimiques avec le bromure de méthyle, qui déterminent les propriétés et le devenir du pesticide. La matière organique réduit par adsorption la concentration en pesticide biodisponible dans l'eau ou l'air du sol. L'amplitude et la faible réversibilité du phénomène affectent la bioactivité et le transfert par diffusion en phase gazeuse. Les molécules irréversiblement adsorbées ne présentent plus d'activité pesticide; elles pourraient être à l'origine d'une persistance du pesticide sous forme de résidus liés. La matière organique est également le principal facteur de la dégradation du bromure dc méthyle dans le sol. Sa réactivité varie toutefois en fonction de sa composition et de son degré d'évolution. La vitesse du phénomène est telle que la dégradation doit représenter un élément important dans le bilan du pesticide. Une optimisation des modalités de traitement, visant à diminuer les doses appliquées et le niveau de résidus bromés formés, doit done tenir compte de ces interactions.
Co‐evolution of potato cyst nematodes and their hosts: implications for pathotypes and resistance1
Authors: STONE A. R.
Published: April 2008

The co‐evolutionary process is believed to have resulted, through interaction of wild populations of potato cyst nematodes and their hosts in geological time, in the resistant hosts now utilized in plant breeding programmes and in nematode populations with genes for resistance‐breaking or virulence. It is argued that all such interactions between highly adapted, truly parasitic plant nematodes and their hosts are likely to be governed by gene‐for‐gene interrelationships. Practical implications of this hypothesis are that only pathotypes (resistance‐breaking races) defined against identified resistance genes are scientifically sound and of practical value; that, in the case of potato cyst nematodes, other pathotypes (Ro2, Ro3, Ro5 and Pa2 and Pa3) should be abandoned; and that oligogenically based resistance to potato cyst nematodes, especially important in providing resistance to Globodera pallida, is non‐durable. Working definitions of the terms ‘pathotype’, ‘host‐race’ and ‘virulence’ are provided.
Breeding for resistance to Globodera pallida at CIP1
Authors: DE SCURRAH M. , FRANCO J.
Published: April 2008

Breeding for resistance to Globodera pallida, at the International Potato Center (CIP), is directed at pathotypes P4A and P5A. The polygenic nature of resistance and the variability of pathotypes complicate breeding and testing for resistance. Recurrent selection for resistance genes and for agronomic characteristics is used to increase resistant gene frequency in potato populations. Mass seedling screening, as an early indicator of segregation ratios in a progeny, and a petri‐plate technique for accurate assessment of resistance in potato clones have proven to be useful aids in selecting for resistance. Clones with partial resistance could be grown by farmers under certain conditions; partial resistance may also be useful in breeding programmes. New differential or tester clones which are better adapted and resistant to P5A populations should be utilized in the Andean region. Although Solanum tuberosum ssp. andigena has been the main source of resistance, especially to pathotype P5A, the CIP breeding programme should now turn to wild species in order to broaden the base of resistance.
Field performance of potato cultivars resistant and partially resistant to Globodera pallida1
Authors: DALE M. F. B.
Published: April 2008

Results of field trials of cultivars resistant or partially resistant to Globodera pallida are reported. The effects of the varying resistance levels on the nematode populations were examined. The initial population levels had an important effect on the Pf/Pi ratio. The ranking of the cultivars using the field Pf/Pi values consistently agreed with the resistance ranking obtained using the closed canister method of assessment. Many of the partially resistant cultivars effectively limited the level of increase of the final cyst‐nematode population, if not decreasing the levels from their initial values. It is argued that such partial resistance can contribute positively to the control of potato cyst nematodes within the context of a crop rotation.
Breeding potatoes with dihaploids1
Authors: UHRIG H.
Published: April 2008

Tissue culture methods, particularly anther culture and protoplast fusion, can be useful tools to overcome some problems in the conventional combination breeding of potatoes. The use of dihaploids facilitates the analysis of segregation patterns of interesting characters, androgenetic derived plants may supply homozygosity and somatic hybridization may result in a predictable combination of selected genotypes. This article reviews current knowledge and results on the incorporation of these techniques into the breeding programme of the Max‐Planck‐Institute for Breeding Research in Köln (FRG), with special reference to resistance including that to Globodera pallida and G. rostochiensis.
Résistance des solanacées àGlobodera et influence de certains facteurs sur les résultats des tests de résistance1
Authors: MUGNIÉRY D.
Published: April 2008

La résistance àGlobodera rostochiensis et àG. pallida chez la quasi‐totalité des clones de pommes de terre connus s'exprime essentiellement par un blocage du développement des larves L2 et, pour les individus qui parviennent a se développer, par une orientation préférentielle vers le phénotype mâle. Tout effet défavorable sur les nématodes accentue ces deux phénomènes. Certains effets, tels que la compétition intraspécifique, le vieillissement des larves et les interactions avec la population choisie comme inoculum standard, sont analysés. Il en ressort que, quel que soil le type de test pratiqué, en pots ou en boîtes de Pétri, il faut porter la plus grande attention à l'origine de l'inoculum et l'idéal est d'utiliser une population se développant bien dans les clones sans résistance. Ce choix fait, il convient de limiter les niveaux de compétition intraspécifique: en boîtes de Pétri, un effectif de cinq larves par racine est un optimum; en pots, une densité de 0,25 larves par g de sol est souhaitable. Pour les tests exécutés en boîtes de Pétri, il faut veiller á ne pas utiliser des larves conservées trop longtemps á basse température, condition classique de conservation qui diminue leur potentiel infectieux.
Standard methods to test the side‐effects of pesticides on natural enemies of insects and mites developed by the IOBC/WPRS Working Group ‘Pesticides and Beneficial Organisms’
Authors: HASSAN S. A. , BIGLER F. , BLAISINGER P. , BOGENSCHÜTZ H. , BRUN J. , CHIVERTON P. , DICKLER E. , EASTERBROOK M. A. , EDWARDS P. J. , ENGLERT W. D. , FIRTH S. I. , HUANG P. , INGLESFIELD C. , KLINGAUF F. , KÜHNER C. , LEDIEU M. S. , NATON E. , OOMEN P. A. , OVERMEER W. P. J. , PLEVOETS P. , REBOULET J. N. , RIECKMANN W. , SAMSOSE‐PETERSEN L. , SHIRES S. W. , STÄUBLI A. , STEVENSON J. , TUSET J. J. , VANWETSWINKEL G. , VAN ZON A. Q.
Published: April 2008

A short description is given of 19 laboratory, 12 semi‐field and 5 field methods to test the side‐effects of pesticides on beneficial organisms. The methods were developed according to standard guidelines by members of the Working Group ‘Pesticides and Beneficial Organisms’ of the International Organization for Biological Control (IOBC), West Palaearctic Regional Section (WPRS); 28 members in nine countries participated and the beneficial organisms (natural enemies of insects and mites) included: 6 Hymenoptera, 4 Coleoptera, 2 Diptera, 1 Neuroptera, 1 Heteroptera, 3 Acari, 1 Aranea, 1 entomopathogenic fungus (Hyphomycetes). There is agreement that a combination of laboratory, semi‐field and field tests is needed to show the side‐effects of pesticides on beneficial organisms and that the beneficials chosen for the test should be relevant to the crop on which the pesticide is to be used.
Potato cyst nematodes: a critical review of the current pathotyping scheme1
Authors: TRUDGILL D. L.
Published: April 2008

The pathotype scheme proposed by Kort et al. (1977) is critically reviewed. It is proposed that many of their pathotypes are artifacts resulting from their using an arbitrary Pf/Pi value of ± 1 and differential clones with quantitatively based polygenic resistance to separate pathotypes. It is concluded that most European populations of potato cyst nematodes are heterogeneous for virulence genes and that Pf/Pi measurements are influenced too readily by several factors, including initial population density, the vigour of plant growth, and the viability of the nematode, to be used as either a measure of nematode virulence or plant resistance. Instead, reproduction should be related to that on appropriate non‐resistant or partially resistant controls and the aim should be to quantify the proportion of virulent individuals in the population. For greatest accuracy it will be necessary to use procedures which minimize genotype × environmental interactions.
Comparison of the Fenwick can and Schuiling centrifuge methods for the extraction of potato cyst nematodes from soil1
Authors: CLAYDEN I. J. , TURNER S. J. , MARKS R. J.
Published: April 2008

An evaluation of the efficacy of the Schuiling centrifuge and traditional Fenwick can methods of extracting Globodera cysts from infested field soils confirmed the accuracy of the Schuiling centrifuge extraction method. Experience has shown that samples with a high organic matter content may reduce extraction efficiency. Improvements in the mechanical and electrical construction of the present Schuiling apparatus are needed, but once they have been made the choice of extraction method in large‐scale statutory and advisory programmes need only depend on considerations such as convenience of use and cost‐effectiveness.
Monitoring and forecasting in plant protection in the German Democratic Republic
Authors: SPAAR D. , EBERT W.
Published: April 2008

In the GDR, a regional pest monitoring scheme run by the State Plant Protection Service collects data on 87 pests for preparing national pest management warnings and recommendations and for strategic planning. Within each farm, plant protection specialists follow a field‐level crop monitoring procedure to guide them in their immediate decision making. Regional ‘standard values for control’, oriented according to national economic requirements, are adjusted in the light of immediate local ecological and agrotechnical conditions into ‘control thresholds’ used for local decision making. Simulation models assist in fixing these control indices. In particular, SIMPHYT I and SIMPHYT II calculate the course of Phytophthora infestans epidemics and provide the basis for the PHYTEB forecasting procedure. These systems have been operational in GDR since 1982 and in general result in saving at least one spray per season. SIMPHYT III, a new system under trial, incorporates fungicide behaviour as well, SIMLEP I has been operational since 1983 and provides forecasts of Colorado beetle populations. Five other such systems are at an advanced stage of development. In orchards control decisions will instead be based on locally installed automatic microchip‐based warning devices. These monitor temperature, humidity, leaf wetness and wind velocity and can be programmed for all the major orchard pests and diseases. Trials in five intensive orchards in 1982/84 have been given very promising results and it is suggested that one such device, representative of an area of 500–1000 ha, could save about 150,000 Marks per annum in reducing the number of ‘insurance’ sprays.
Recent situation of the Colorado beetle (Leptinotarsa decemlineata) in Poland
Authors: PIEKARCZYK K. , LIPA J. J.
Published: April 2008

During the last 20 years there have been two outbreaks (1972 and 1976) of the Colorado beetle and one decline (1980). The new outbreak in 1983 was unusually massive as the population density of the pest was 2–3 times higher than in previous years. Almost 100% of potato crops and more than 50% of plants were attacked by the pest. This was due to low mortality of hibernating beetles during winter of 1982/83 and very favourable weather conditions in 1983 which resulted in an early emergence of hibernating beetles in the spring, intensive migration and high female fecundity. In 1983 insecticide treatments were applied to an area of 3.49 million ha as compared to 1.8 million ha treated in an average year. In 1984 there was a serious decline of the Colorado beetle population.
Further development of a computer model for simulating pest life cycles
Authors: BAKER C. R. B. , COHEN L. I.
Published: April 2008

Modifications to the PETE computer model developed at the University of Michigan, USA are described. These include: routines to allow use of non‐linear relationships between temperature and rate of development or progress of diapause, as alternatives to temperature sums; thresholds for ecdysis to mimic synchronisation observed in natural populations; adult activity levels and oviposition optionally controlled by temperature, sunshine and rainfall; calculation of day length and temperature at the time of the daily peak of adult activity; obligatory diapause; photoperiodic induction of facultative diapause and preliminary ideas on simulation of microclimate. Validation is discussed particularly in relation to simulating the life cycle of the Colorado beetle.

Les modifications apportées au modèle informatique PETE, mis au point à l'Université du Michigan (USA), sont décriles. Elles comprennent: 1) des méthodes pour utiliser des relations non linéaires entre la température et le taux de croissance ou le cours de la diapause plutôt que les sommes de températures; 2) des seuils pour l'ecdysis entraînant une synchronisation observée dans des populations naturelles; 3) les niveaux d'activité des adultes et l'oviposition éventuellement contrôlés par la température, l'ensoleillement et les précipitations; 4) le calcul de la longueur du jour et de la température au moment du pic journalier d'activité des adultes; 5) la diapause obligatoire; 6) l'induction photopériodique d'une diapause facultative et des éléments préliminaires sur la simulation du microclimat. La valeur du modèle est discutée, en particulier dans le cas de la simulation du cycle biologique du doryphore.
Detection of plum pox virus in Spain
Authors: LLÁCER G. , CAMBRA M. , LAVIÑA A.
Published: April 2008

Until recently, plum pox (sharka) virus (PPV) was never detected in Spain on any of the material analysed by the enzyme‐linked immunosorbent assay (ELISA). It was only in June 1984 that the virus was first detected by two different antiscra in Japanese plum trees (Prunus salicina), cv. Red Beaut, showing typical symptoms of the disease. The detection was later confirmed by graft‐transmission to GF‐305 peach seedlings, and also by immunoelectron microscopy. The PPV was experimentally transmitted from GF‐305 to GF‐305 by aphids and from GF‐305 to herbaceous plants by mechanical inoculation. Thus far (January 1985), PPV has been detected basically in Japanese plum trees in Sevilla, Murcia, Valencia and Castellón, in apricot in Castellón, and in peach trees in Sevilla and Lérida.

De nombreuses analyses par la méthode ELISA n'ont, pendant longtemps, pas permis de détecter le plum pox virus (agent de la sharka) en Espagne. Ce n'est qu'en juin 1984 que la présence du virus a été confirmée, par l'utilisation de deux antiséra différents, chez des pruniers japonais (Prunus salicina) cv. Red Beaut qui manifestaient des symptôines typiques de la maladie. La détection a été confirmée par greffage sur des plants du pêcher GF‐305, ainsi que par microscopie immuno‐électronique. La transmission du PPV de GF‐305 à GF‐305 a été réalisée à l'aide de pucerons et de GF‐305 à des plantes herbacées mécaniquement. A cette date (janvier 1985). le PPV n'a été détecté quc dans des prunicrs japonais dans, les provinces de Sevilla, Murcia, Valencia et Castellón, ainsi que dans des abricotiers en Castellón et dans des pêchers en Sevilla et en Lérida.
Morphological and physiological characteristics of dicarboximide‐sensitive and resistant isolates of Botrytis cinerea1
Authors: LORENZ G. , POMMER E.‐H.
Published: April 2008

Various morphological and physiological characteristics, such as mycelial colour and appearance, mycelial growth rates, sporulation, pathogenicity on different hosts, activity of cell‐wall degrading enzymes, competitive ability and osmotic sensitivity of five dicarboximide‐resistant isolates of Botrytis cinerea were compared to those of their sensitive parent strains. There were only small reductions in mycelial growth rates of resistant strains as compared to the sensitive ones, whereas all of them showed greatly reduced rates of sporulation. With only one exception, the pathogenicity of the resistant isolates was reduced by varying extents compared with the sensitive parent strains. While the proteolytic activity of resistant strains tended to be higher, the activities of peclolytic enzymes were often lower than those of the sensitive isolates. In competition tests, resistant conidia often completely disappeared after a few passages on untreated plants. In only one of the resistant isolates tested so far was dicarboximide resistance related to a high osmotic sensitivity.
Failure to detect highly resistant strains in dicarboximide resistant field populations of Botrytis cinerea1
Authors: KATAN T.
Published: April 2008

Field isolates of Botrytis cinerea with moderate levels of resistance to dicarboximide fungicides (ED50 1.0–4.9 μg ml−1) and to dicloran were obtained from glasshouses where vinclozolin and iprodione failed to control grey mould. From sensitive and moderatcly‐resistant cultures, laboratory isolates were selected on dicarboximide‐amended medium, which were highly resistant to these fungicides (ED50 125‐>3000 μg ml−1). Conidia of all the resistant isolates germinated well on media amended with 100 μg ml−1 of the dicarboximides vinclozolin, iprodione, procymidone and myclozolin and with 5 μg ml−1 of metomeclan. However, the spores of the moderately resistant isolates did not germinate on 100 μg ml−1 metomeclan while the spores of the highly resistant isolates germinated well. Using media with 100 μg ml−1 of metomeclan to distinguish between the two phenotypes, no highly resistant strain was detected among 312 resistant samples from five cucumber glasshouses with a high frequency of moderately resistant strains. From air‐borne inoculum of five glasshouses with 100% resistant populations, 1604 colonies were recovered on vinclozolin‐amended (100 μg ml−1) medium and none on metomeclan‐amended (100 μg ml−1) medium. It is concluded that strains of B. cinerea highly resistant to dicarboximides are absent from field populations.
Caractéristiques culturales et pathogéniques de souches de Botrytis cinerea résistantes aux imides cycliques isolées de fraisiers en Belgique1
Authors: MEUNIER S. , MARAITE H. , MEYER J. A.
Published: April 2008

La DE50 de vinchlozoline pour des souches de Botrytis cinerea isolées de 1980 à 1984 varie de 2 μM a plus de 300 μM de vinchlozoline, néanmoins 93% des souches présentent une DE50 comprise entre 2 et 24 μM. En l'absence de fongicide, la capacité saprophytique et pathogéne des souches résistantes est dans l'ensemble égale ou légèrement inferieure à celle des souches sensibles. En présence de vinchlozoline, à des concentrations inhibant les souches sensibles, les souches résistantes colonisent les féves, les paprikas ou les rondelles de concombre; toutefois, les substrats traités sont généralement moins rapidement colonisés que les témoins non traités. Ce retard augmente avec la concentration en fongicide et diminue lorsque le niveau de résistance de la souche croît; les souches à DE50 supérieure á 300 μM de vinchlozoline ne sont plus affectées par le traitement. L'association de la vinchlozoline avec d'autres fongicides présente un effet synergique sur certaines souches. Le mélange vinchlozoline+tolylfluanide réduit la fréquence d'apparition de colonies résistantes in vitro. Les souches + DE50 supérieure à 300 μM sont plus sensibles aux pressions osmotiques élevées quc les souches sensibles.
Dynamics of the response of barley mildew to the use of sterol synthesis inhibitors1
Authors: WOLFE M. S.
Published: April 2008

Since 1980, the increase in the use of triazole fungicides to control Erysiphe graminis on barley in the UK has been accompanied by an increase in the frequency of pathogen isolates with different levels of reduced sensitivity to the fungicides. In each year, the rate of change varied, probably in relation to the degree of selection at different times in the host life cycle. In the first years, isolates with reduced sensitivity were less pathogenic than sensitive strains on a range of host cultivars. These differences were less obvious on cultivars with the Mla6 and Mlv resistance genes. More recently, reduced sensitivity has become widespread in the pathogen population and the general pathogenicity of this part of the population has increased. As a result, the yield benefit previously associated with mildew control by the triazoles is becoming severely diminished. This effect is not due primarily to the increase of highly insensitive isolates, but to the high frequency of isolates with intermediate insensitivity that are able to cause epidemic increase of the pathogen soon after fungicide application.
Sensitivity of Erysiphe graminis f. sp. hordei to ethirimol in relation to field performance in UK1
Authors: HOLLOMON D. W. , LOCKE T. , PROVEN M.
Published: April 2008

When introduced as a seed treatment 5 years ago, triadimenol (Baytan) was more effective against Erysiphe graminis f. sp. hordei than was the alternative ethirimol (Milstem). This contrasts with the current situation on the powdery mildew‐susceptible cv. Golden Promise, where ethirimol is generally better than triadimenol. In part this reflects a decline in the performance of triadimenol seed treatment, as a result perhaps of some decrease in sensitivity to this fungicide. However, laboratory assays of field isolates also revealed that negatively correlated cross‐resistance between triadimenol and ethirimol might exist. In field trials the sensitivity of E. graminis to triadimenol was indeed increased after treatment with ethirimol, but triadimenol hardly altered sensitivity to ethirimol. The possible causes of these changes in fungicide sensitivity are discussed.
Résistance à la dodine chez Venturia inaequalis dans les vergers de pommiers de l'Italie septentrionale1
Authors: CESARI A. , FIACCADORI R. , BRANDOLINI V.
Published: April 2008

Des recherches réalisées au cours des trois dernières années sur l'éventuelle variation de la sensibilité de Venturia inaequalisà la dodine ont mis en évidence la résistance de certaines populations à ce fongicide, utilisé depuis très longtemps et de façon intensive dans les vergers d'Italie septentrionale. Les résultats ont été obtenus dans des vergers traités à la dodine depuis aumoins 10 ans. Les mêmes échantillons ont montré une variation de la sensibilitéà la dodine au cours des applications d'une seule saison.
Resistance to benzimidazoles in Pseudocercosporella herpotrichoides1
Authors: FEHRMANN H.
Published: April 2008

In a long‐term monitoring experiment in winter wheat between 1976 and 1980 no substantial change in the benzimidazole resistance of Pseudocercosporella herpotrichoides was observed; carbendazim or related chemicals were applied twice a year. In 1982, a high percentage of the fungus population was benzimidazole‐resistant. There is no conclusive explanation for this sudden change. Paralleling this development, since 1982 farmers in northern Germany complain about failures in eyespot control with benzimidazole‐type fungicides. In a survey in 1983 (52 fields from all over the country; 10 haulms per field), spore germination tests (on 2 ppm carbendazim) in nearly 50% of the fields showed the fungus population to be carbendazim‐resistant. This result was confirmed by other findings (disease assessment, yield data). In 1984, plants were again taken from more than 150 unsprayed plots all over the country. This time benzimidazole resistance was expressed by the frequency of isolates on carbendazim‐containing medium (100 haulms per field). The previous results were confirmed. Benzimidazole resistance is still much more a problem in northern than in southern Germany. There seems to be some relationship between benzimidazole resistance in the field and the history of benzimidazole‐type applications on the plot.
Benzimidazole resistance in Pseudocercosporella herpotrichoides—monitoring programme in Denmark1
Authors: NIELSEN B. J. , SCHULZ H.
Published: April 2008

Surveys in Denmark show decreasing effectiveness of benzimidazole fungicides against Pseudocercosporella herpotrichoides since 1980, and a high% of fields with resistant isolates of the fungus. Farmers have only escaped serious losses because of good weather at harvest. New recommendations are made for fungicide use.
Laboratory studies on benzimidazole resistance in Septoria tritici1
Authors: GRIFFIN M. J. , FISHER N.
Published: April 2008

A technique is described for testing isolates of Septoria tritici from winter wheat for resistance to benzimidazole fungicides. Secondary spores from 23 isolates were tested on Czapek Dox V‐8 agar amended with benomyl at 1–10 μg ml. Twenty‐one isolates were recovered from eight crops in England in 1984 and two (PBI isolates) were obtained in 1973. Thirteen isolates, including both PBI isolates, were sensitive to benomyl at 1 μg ml−1 and nine were resistant at 10 μg ml−1. The remaining isolate had a low proportion (1:3.7 x 104) of resistant spores. The minimum inhibitory concentration for sensitive isolates was 0.2–0.4 μg ml 1 benomyl and for resistant isolates was more than 1000 μg ml 1. Benomyl‐resistant isolates were cross‐resistant to carbendazim, thiabendazole and thiophanate‐methyl, but not to 12 other fungicides with different modes of action. The implications of these findings are discussed.
The genetic basis of classification of fungicides according to resistance risk1
Authors: GEORGOPOULOS S. G.
Published: April 2008

In order to render a chemical ineffective, target organisms must possess appropriate genetic variability. Depending on whether plant pathogenic fungi can meet this requirement, our agricultural fungicides can be classified into three groups characterized as follows. 1) Major changes in sensitivity result from single‐gene mutations. Such major genes are apparently present in all sensitive species. Risk of control failure is high or moderate, depending on the effect of resistance mutations on fitness. 2) Single‐gene mutations have small effects on sensitivity. Positive interaction between several mutant genes often leads to a stepwise increase in resistance, but usually at an increasing cost in terms of fitness. Resistance risk is low to moderate. 3) Ability for mutational modification of sensitivity never demonstrated, so that appropriate variability is apparently unavailable and low, if any, resistance risk is involved. The paper examines what evidence is available for the classification of each important agricultural fungicide into one of the above groups and what are the implications of this classification on disease control strategies.
Integration of host resistance and fungicide use1
Authors: WOLFE M. S.
Published: April 2008

The current strategies for using host resistances and fungicides encourage the increase of pathogen strains with matching pathogenicity or insensitivity. Diversification of cultivars and fungicides is recommended, but involves only diversification between crops and does not include integration of the two methods of control. A strategy of complete or total diversification requires diversification within as well as between crops. For example, the system of using cultivar mixtures can provide assured high yields, even though control of pathogen development is incomplete. Within‐crop diversification of fungicides applied to seed is becoming a practical possibility with the development of film‐coating of carriers that can adhere different materials firmly to different seeds whilst maintaining uniform seed‐flow characteristics. An ideal system would involve integrated total diversification of host cultivars and fungicides. Field data indicate that this can provide excellent profit margins and disease control, while maximising evolutionary problems for the pathogen. The system is technically feasible using developed methods of cultivar mixing together with the new technique of film‐coating.