bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of the Common Vole, Microtus arvalis (Pallas) on Winter Wheat and Alfalfa Crops1)
Authors: Tertil R.
Published: April 2008

Impact of the common vole, Microtus arvalis (Pallas), upon the winter wheat and alfalfa crops was determined. Net‐bottomed coops were used for estimating the effect of vole grazing. Exposure of winter wheat to vole grazing at the stages of earing and flowering was the most harmful. Losses were up to 91% of the potential crop yield, while the proportion of the best grain size fraction (2.8 mm) dropped to a minimum level. Coefficients reflecting the influence of vole grazing on the crop were determined. The coefficient TOTAL is an index of the total impact of consumption. The impact, It, at time t equals the consumption, Ct, at this time multiplied by the value of TOTAL. For alfalfa, these coefficients range from 1.28 to 11.73. The results obtained in this study have made it possible to determine the effective rodent pressure on crop yield.
Small Rodent Abundance in Relation to Reforestation Measures and Natural Habitat Variables in Northern Sweden1
Authors: Larsson T.‐B.
Published: April 2008

Results of an extensive survey, 1972–1975, aimed at establishing the influence of forest management practices and other environmental variables on small rodent abundance are discussed. The study area included several habitat types and, in total, 1,878 small quadrats were marked out in 47 regeneration areas. Most areas were sampled twice a year, in the spring and autumn, and more than 5,000 voles were trapped; the species Clethrionomys glareolus (Schreber) and Microtus agrestis (L.) were trapped in about equal numbers, while C. rufocanus (Sundevall) was rather sporadic. The cycle increase started earlier in C. glareolus than in M. agrestis and C. rufocanus.

Data on environmental variables were collected partly by means of field observations and pardy from the literature. An analysis of the effect of environmental variables revealed considerable interaction making identification of primary factors difficult. The populations of C. glareolus and C. rufocanus generally decreased with an increase in time since clear‐cutting. For M. agrestis, highest numbers were found on sites in which clear‐cutting had been carried out 5–15 years previously. The influence of surface treatment, in particular, was found to be dependent on the population cycle. During increase and early peak phases, C. glareolus was found in smaller numbers in regenerated areas treated by burning or ploughing, compared with those where only normal patch scarification had been carried out. During the very gradual decline in numbers, conditions were the reverse. During increase and early peak phases, the highest catches of M. agrestis were made in scarified areas. This inverse relationship between the 2 species was also found in connection with many of the other environmental variables studied. M. agrestis was the most typical “regeneration phase” species, positively influenced by environmental factors such as moderately coarse grained soil texture, low soil acidity, moderate humus thickness, increasing moisture up to a certain level and a vegetation type with forbs predominating as opposed to the Vaccinium type. The pattern of displacement indicates that competition occurs between M. agrertis and C. glareolus.
Regulatory Mechanisms and Dynamics of an Island Population of Clethrionomys glareolus (Schreber, 1780)1
Authors: Bujalska Gabriela
Published: April 2008

A scheme of density regulation in an island population of Clethrionomys glareolus (Schreber) is presented. The key factor for the changes in numbers was mortality of untrappable voles. A peak in population numbers followed low mortality of the spring generation, and, in peak years, mortality of the autumn generation was always high. An experimentally enriched food supply resulted in low mortality of both the spring and autumn generations. Natality, which is usually stable, increased slightly as a consequence of the additional food supply. This was due to an earlier start of the breeding season (6 weeks earlier) and to an increase in numbers of mature (i.e. capable of reproduction) females.
Method of Selecting Preferred Baits and Rodenticides1
Authors: Howard W.E. , Marsh R.E.
Published: April 2008

To conduct bait‐choice tests, with species that will enter bait boxes, requires at least 10 bait boxes (25–40 cm long and about 20 cm deep) with openings at opposite corners, for exposing 3 to 5 trays of potential baits. Floors of boxes are dusted with a thin layer of talc or ground clay. The same boxes can be used to determine acceptance of the proven preferred bait treated with different rodenticides at different concentrations, except that different toxicants cannot be compared in the same box unless only chronic (multiple‐feeding) anticoagulants are used. Tracking tunnels or stations can be used to obtain a relative pre‐ and post‐control census of rodent populations. They are especially useful for determining whether there are survivors. If there axe survivors, the above non‐toxic bait‐acceptance tests and acceptance of prepared toxic bait tests must be repeated, for it is paramount to learn why the survivors were not poisoned.
Bromadiolone, a New Anticoagulant Rodenticide1
Authors: Marsh R.E.
Published: April 2008

A search for more effective anticoagulant rodenticides has brought about the development of a new compound, coded LM‐637, and temporarily named bromadiolone. Results of efficacy tests on 10 rodent species are discussed in detail. The compound was found to be a very potent and highly palatable anticoagulant which is capable of achieving 100% mortality in Norway rats, Rattus norvegicus (Berkenhout), with 1‐day feeding. Efficacy was demonstrated on all 3 commensal rodents and several important agricultural rodent pests native to the United States. A relatively few feedings (1 to 5 days) of bait containing 0.005 % bromadiolone produced death in most species tested. These rodenticidal properties make bromadiolone a most promising control agent.
Ecological and Toxicological Bases of Directed Control of Arvicola terrestris (L.) and Microtus arvalis (Pallas) in Agricultural Crops 1
Authors: Bykovski V.A.
Published: April 2008

In order to protect crops during outbreaks of Arvicola terrestris (L.) or Microtus arvalis (Pallas), it is necessary to have formulations with acute action and high rodenticidal potential; rodenticides should be applied as baits corresponding to the hygrotrophic specialization of the species. When compared with zinc phosphide, Gliftor provides reliable control of voles in any season. The outlook of bactorodencide (bacterial preparation) applications is being determined with particular reference to their ecological effects.
Effectiveness of Nuvacron in Controlling Microtus arvalis (Pallas)1
Authors: Tuta Al. , Hamar M.
Published: April 2008

Studies were carried out on the rodenticidal effect of Nuvacron (40% emulsifiable concentrate) applied in 5 different dosages to clover crops and natural pastures subjected to high population densities of Microtus arvalis (Pallas).

The mechanical application of a single treatment per year (late in September) with Nuvacron 40% emulsifiable concentrate, at the rate of 3.51/6001 water/ha, resulted in a low density of this pest. Similar results were also obtained when the pesticide was tested on a 35 ha area, under commercial conditions. Consequently, its use is recommended for the control of M. arvalis in alfalfa and clover seed crops.
Experience in Denmark with Cereal Cultivars Resistant to Cereal Cyst Nematode (Heterodera avenae Woll.)1)
Authors: JAKOBSEN J.
Published: April 2008

On the basis of investigations on the cereal cyst nematode's distribution, it is presumed that one third of all the cereal growing areas in Denmark is infested to a degree, and that yield losses of 5 % or more may be assumed. This means an annual loss of about 100 million D.Kr. By using resistant cultivars every second year, the population of Heterodera avenae Woll. can be kept at a harmless level. It may be assumed that intensive growing of nematode‐resistant cereals includes a risk of promoting the occurrence of pathotypes other than the 2 known to exist in Denmark. So far, there is no indication for their existence.
Control of the Spiny Bollworm [Earias insulana [Boisd.]) in Cyprus
Authors: MELIFRONIDES I.D. , ZYNGAS J.Ph. , MARKOULLIS G.
Published: April 2008

Damage caused by larvae of Earias insulana Boisd. is of great economic importance to growers of okra (Hibiscus esculentus) in the areas of Kiti‐Perivolia, on the south‐east coast of Cyprus, near Larnaca. In order to minimize the damage caused by larvae feeding on okra fruits, several organophosphorous and organo‐carbamate insecticides with relatively low mammalian toxicity were tested during the years 1972, 1973, 1976 and 1977. Permethrin, methomyl, pirimiphos‐methyl and chlorpyrifos gave encouraging results.
Resistance and Resistance Breeding in Ornamentals 1
Authors: ZELLER W.
Published: April 2008

Heritability studies in ornamentals with regard to Erwinia amylovora (Burrill) Winslow et al. were started shortly after the introduction of the pathogen into northern Europe. Since that time, approximately 8,000 plants from 17 genera of Rosaceae have been tested; 7 genera were reported to be susceptible: the economically important Cotoneaster, Crataegus, Cydonia, Pyracantha, Sorbus, and, in addition, Chaenomeles and Stranvaesia. Moreover, 9,000 Cotoneaster seedlings comprising 15 cultivars were tested and the surviving individuals used for breeding purposes. The variation between these first results reported in the different European countries and some American findings is considerable because of different inoculation procedures and various epidemiological conditions. However, resistance sources have been identified and it would be desirable to start co–operation in this field on an international level.
Establishment of Integrated Control Systems1
Authors: KOCH W.
Published: April 2008

The integration of special measures into a system requires the evaluation of their absolute and relative importance. Processes have to be known and ways of their mathematical simulation are necessary. The very first steps have been done in this direction in weed science. One of the key factors for such simulations is the population dynamics of weeds and within this the dynamics of reproduction and survival is of special importance. Integrated control systems can be established. They could be much improved with a better understanding of the key factors and the interrelationships involved.
On–line Reduction of Microclimate Data on Turbulent Transfer of Moisture Using a Minicomputer1)
Authors: LENGKEEK J.G.
Published: April 2008

In research on the microclimate, data reduction is a necessity for the measurement of turbulent quantities. This can be a simple action, such as averaging, or a more complex one, such as correlation. Under conditions of neutral atmospheric stability, the measurement of turbulent transport quantities can be restricted to computing averaged profile gradients. Since minicomputers are available now for field application, direct measurement of turbulent transport is becoming increasingly attractive. This can be performed both by analogue and digital correlation techniques. The minicomputer applied as a digital correlator is preferable, because of its complete programmability.

The application of an on–line minicomputer for measurement of the turbulent flux density of impulse and water vapour is presented in this paper. Specific attention is paid to problems concerning scanning rate and aliasing.
Simulation d'une épidémie deSeptorJ'a nodorum Berk, sur blé, étude des possibilités de résistance horizontale1)
Authors: RAPILLY F.
Published: April 2008

Sommaire

Les épidémies en pathologie végétale peuvent être représentées comme un systéme à compartiments comprenant un échange cyclique et un échange simple. Un modéle permettant de simuler une épidémie de septoriose àSeptoria nodorum a été construit. L'interrogation du modéle a permis de dégager les paramétres (vitesse de progression de la surface contagieuse, période de latence, port des feuilles) qui permettent de diminuer la vitesse de progression de L'epidémie par unité de temps et done d'augmenter le niveau de résistance horizontale de la population–hôte.
Systems Approach to Pest Management1)
Authors: TUMMALA R.L. , HAYNES D.L.
Published: April 2008

The principles and concepts which provide an overall prospective for coordinating modeling activities with other aspects of the environment to obtain ecologically and sociologically compatible and economically feasible –pest management –are discussed.

The discussion on off–line use of models emphasizes the utility of the models of different complexity in research and management. The use of simple models in the on–line management emphasizes the fact that the accuracy of the model can be sacrificed for more information from the real system. To this extent, implementation does not have to wait for complete and very accurate model development. On the other hand, research and understanding of the ecosystem will increase from complex modeling efforts and should continue.
Data Banks on Pesticides: A Feasibility Study1)
Authors: SCHOLTEN K.F.
Published: April 2008

Pesticide management is characterized, in terms of government responsibility, by an increasing need for flexibility to cope with fast change in science, technology, agricultural practice and environmental policy.

The feasibility study in question was started at the end of 1974, when it became clear that the variety of conventional information systems often caused delay, especially in the administrative follow–up of the official procedures with which government is involved. This concerns approval and registration as well as providing pesticide information to quite a variety of interested parties, such as industry, importers, dealers, users of pesticides and government agencies (Plant Protection Service, Extension Services, Public Health and Environment Authorities, Labour Inspectorate, etc.).

The computer–based pesticide management information system which is being developed now by a multi–disciplinary project–group should meet the needs of all those having government responsibility in the field of pesticide management.

It is planned as an on–line, geographically dispersed retrieval and storage system with terminal facilities for all users. The system is to be controlled by the Pesticides Bureau of the interdepartmental Committee for Phytopharmacy.
Prediction of Pests, Diseases and Losses: Principles and Computer Applications1
Authors: BENEDEK P.
Published: April 2008

Efficacy of plant protection is closely related to an appreciation of the seasonal development and population changes of harmful organisms. This necessitates national surveys on pest population dynamics and on the epiphytotics of plant diseases. From these surveys, regional forecasts can be produced to give advice to the farmers. This work needs highly sophisticated systems to cover both numerical and spatial aspects of pest situations. Thus, there is an urgent need to exploit computer applications in solving forecasting problems. However, the use of computers for forecasting the incidence of harmful organisms and losses is in its initial phase. At present, single pest and disease models prevail. Numerical aspects have been approached both empirically and experimentally. Empirical models, based on multiple regression analysis, are relatively simple and easy to use for various harmful organisms. However, simulation models of harmful organisms are expected to lead to much more reliable results, although, so far, little experience is available on their predictive powers in crop protection. Spatial aspects have been approached with a routine computer mapping technique, which seems to be an effective tool for recognizing and forecasting distribution trends, while loss predictions can be based on crop models, incorporating submodels forecasting the incidence of harmful organisms. The prospect for operational use, in forecasting, of the computer techniques mentioned is discussed.
Biologie du doryphore
Authors: BERRE J.R. Le , LOUVEAUX A.
Published: April 2008

Des populations de doryphores sont réguliérement observées depuis 25 ans, au cours de deux visites annuelles. Ces visites ont lieu selon un parcours déterminé, le long du littoral occidental du Département de la Manche. Les dénombrements d'adultes, de pontes et de larves sont effectués par échantillonnage dans une centaine de cultures. Des données quantitatives et suivies ont été recueillies sur la progression de la contamination par les doryphores, soit par déplacement au sol, soit par vol, dans les nouvelles cultures de printemps. La densité des populations imaginales et larvaires et ses variations d'année en année sont connues pour une vingtaine de localités du littoral. Le taux moyen de multiplication des imagos parfaits printaniers (Ipp) reste élevé en dépit de la lutte obligatoire contre le doryphore. Les causes des importantes fluctuations numériques observées tiennent assurément aux caractéristiques biologiques de l'insecte et aux façons culturales propres à la région. La connaissance des caractéristiques du potentiel biotique du doryphore est essentielle à une meilleure compréhension de la dynamique des populations dans le Cotentin et concerne directement le problème de la protection des lies Anglo‐Normandes. Ce sont en particulier les capacityés de dispersion et de résistance au jeǔne des Ipp qui ont été analysées au laboratoire alors que le test de l' envol est utilisé comme critère pour expérimenter la capacityé de dispersion du ravageur. L'aptitude à l'envol des doryphores printaniers, qui est nulle immédiatement après l'émergence du sol, croǐt pendant les 10 premiers jours à 25oC. L'éclairage continu épuise rapidement les individus et le jeǔne prolongé ainsi que l'absence d'eau en augmentent la mortalité, mais la capacityé d'envol des survivants reste néanmoins élevée.
Relations entre le doryphore et sa plante‐hôte
Authors: MOREAU J. P.
Published: April 2008

La persistence de populations de doryphores à des niveaux élevés dans certaines régions de France (et en Europe du Nord au‐delà du 45e degré de latitude) a deux causes possibles: la culture de variétés précoces et tardives situées les unes à cǒté des autres, principalement en petites parcelles, et la synchronisation entre les stades de développement de l'insecte et de la plante. La résistance de la pomme de terre à cet insecte a étéétudiée depuis longtemps. Des croisements entre des espèces sauvages de solanacées et Solarium tuberosum ont constitué l'essentiel des directions suivies. De grandes difficultés ont été rencontrées, surtout dans l'obtention d'hybrides à partir des graines, à cause de la variabilityé géographique des réponses de l'insecte et des relations inverses entre la productivityé et les niveaux de glycoalcaloïdes dans les tubercules. A l'heure actuelle, la recherche est surtout axée sur le choix de variétés de S. tuberosum, en fonction de facteurs écologiques et culturaux, et de la physiologie de la plante. Dans le présent travail, sept variétés ont été plantées dans les conditions de plein champ. La ponte des femelles de doryphore, le nombre de larves obtenues, la consommation du feuillage et le rendement de la culture ont été considérés. Un variété (Résy), qui est peu sensible au mildiou, s'est montrée défavorable à la fois aux adultes et aux larves pendant trois années consécutives. Ainsi l'emploi judicieux d'une ou de plusieurs variétés peut affecter la dynamique des populations de ce ravageur. L'utilisation raisonnée des variétés peut ětre utilisée dans des programmes de protection intégrée contre les ennemis de la pomme de terre.
Colorado Beetle in the Channel Islands
Authors: THOMAS G. , WOOD F.
Published: April 2008

An account of the Colorado beetle in the Channel Islands is given which records the successful results obtained there in preventing the establishment of this serious crop pest. This has been achieved by means of extensive efforts within the Islands and by sustained international cooperation with France, through the auspices of EPPO, to prevent sea‐borne invasions from the Cotentin peninsula which threaten the Islands annually. This campaign has been amply justified and, as a result, no sea‐borne invasions have occurred in the Islands from 1965 to 1975 and precautionary spraying of the potato crops there was discontinued in 1966.
Control Measures Towards Colorado Beetle Eradication in Sweden
Authors: GRÄNSBO G.
Published: April 2008

Sweden suffered a heavy invasion of Colorado beetle in 1972, leading to the establishment of numerous infestation foci in the southern part of the country. The central campaign organized in the following years culminated in the eradication of the beetle by 1978. The beetle has the potential to survive and cause economic damage in Sweden.
Plant Protection Forecasting Service in the Federal Republic of Germany1
Authors: UNRUH M.
Published: April 2008

In the Federal Republic of Germany, plant protection is a matter for the several Federal Lander. Each of the regional plant protection offices has built up a warning system of its own, although there are no essential differences between them. The warnings are based on field investigations which are mostly carried out by technicians. However, it is not possible to inspect all fields, orchards, etc., as the areas of crops are too vast. Warnings follow a general pattern: information on the situation, followed by conclusions on further development; recommendations for control measures; and, most importantly, indications of possible undesired or even dangerous side‐effects and how to avoid them. The warnings are published and also distributed by telephone and radio. Warnings on sugar beet in the Nordrhein area are distributed by the sugar factories to each of the farmers concerned. The forecasting service can certainly be improved by scientific progress. On the other hand, practical improvement is indispensable. The main problem is how to get more information from the field. There is little hope that the personnel situation will change fundamentally, but every effort must be made, in view of the importance of the forecasting service.

En République féderale d'allemagne, les Lander sont chargés de la protection des végétaux. Les bureaux régionaux ont développe leurs proprés systemes de prevision, mais ceux‐ci sont neanmoins très semblables. Les avertissements sont basés sur des observations de plein champ qui sont réalisées pour la plupart par des techniciens. I1 n'est pas possible d'inspecter tous les champs, vergers, etc., en raison des enormes surfaces en jeu. Les avertissements reposent sur un système normalisé comprenant I'information sur la situation présente, suivie d'une évaluation de I'evolution ulterieure, dune recommandation sur les methodes de lutte, d'une indication sur les effets secondaires indesirables ou dangereux, ainsi que des moyens de les eviter. Les avertissements sont expedies sous forme de bulletins, ou communiques par telephone ou par radio. Dans la région de Nordrhein, les avertissements concernant la betterave sont distribues aux exploitants par les sucreries. Le système de prevision peut certainement btre ameliore, surtout sur le plan pratique en beneficiant des progres scientifiques qui sont realises. I1 est essentiel de mutiplier les observations de plein champ, mais il est improbable que les services responsables puissent disposer du personnel necessaire. Cependant, face à I'importance de la prévision, il faut tirer le meilleur parti des moyens disponibles.
Le problème des singularités en climatologie1
Authors: MUELLER W.
Published: April 2008

Les singularités en climatologie, dont la signification a longtemps été controversée, se rapporte à L'existence de fréquences relatives dépassant sensiblement les écarts de certains éléments météorologiques (ou d'une combinaison de certains éléments rnétéorologiques) à certaines époques de L'annee sous latitudes moyennes. II est certain que la prise en considération de données quotidiennes, exprimant le risqué qu'une combinaison de valeurs bio‐météorologiques soit dépassée, améliore sensiblement la connaissance de la réponse biologique, et donc L'importance pratique des modèles de prévision. La fréquence relative statistiquement etablie d'une certaine singularite clirnatique au cours de 10, 20 …. n années d'observation (assez variable en fonction des oscillations climatiques) se révèle souvent décisive, par exemple, pour la réussite d'une récolte. L a singularité des « Saints de glace » (entre le 7 et le 14 mail en Europe occidentale et centrale a moins d'importance sur les dommages que subissent les plantes que ceux qu'entraine la singularité de la mi‐juin, en admettant que les températures et le taux d'humidité soient les mêmes. L'utilisation potentielle des singularites dans L'établissement de modéles réalistes prévisionnels de lutte contre les déprédateurs est démontrée.

Climatological singularities, whose significance has long been debated, are relative frequencies which exceed certain deviations in particular meteorological conditions (or combinations of these) from the seasonal norm in medium latitudes, which may recur year by year with a certain regularity. Knowledge of the probability that certain meteorological values will be surpassed on given days is undoubtedly useful for the understanding of biological responses, and therefore for forecasting models. The statistical frequency of particular singularities over 10, 20 or more years (which will vary in relation to climatic oscillations) is often critical for the success of certain crops. Assuming the temperature and humidity of the air to be the same, the early May singularity (“Eisheilige” 7–14 May) in Western and Central Europe is probably less important than the mid‐June singularity as far as damage to plants is concerned. These singularities can usefully be included in realistic forecasting models in plant protection.
Choix des éléments et de leurs limites dans L'établissement de modèles biométéorologiques1
Authors: PRIMAULT B.
Published: April 2008

Le chercheur qui se propose d'établir un modèle biométeorologique est placé devant L'alternative de suivre les phénomènes de la vie dans toute leur complexité ou de ne tenir compte que des impératifs de la pratique. Dans le premier cas, il doit pouvoir s'appuyer sur les systèmes les plus raffinés d'acquisition de données tant météorologiques que biologiques et disposer d'auxiliaires importants, en particulier d'un ordinateur à grande puissance, capable de lui démontrer de façon statistiquement irréfutable que les relations supposeées existent réellement. Dans le second cas, quelques indications très simples ne nécessitant qu'un matériel rudimentaire sont seules à envisager. Il semble done qu'il y ait opposition suivant L'option qui est prise, mais en réalité les deux approches sont étroitement liées et complémentaires. On a vu que le climat subissait, en un lieu donné, des variations importantes d'une année à L'autre et que certaines époques ou dates connaissent des revirements non négligeables. Par conséquent, seule une étude très approfondie des répercussions d'accidents météorologiques sur L'être vivant (organisme nuisible, parasite, prédateur ou hôte) permet de situer les limites de développement possible. Mais L'étude climatologique montre également quels sont les éléments principaux que le praticien doit observer ou mesurer et les seuils critiques auquels il faut se référer. Ainsi, si seuls des chercheurs disposant de laboratoires très bien équipés peuvent suivre le premier parti de L'alternative, d'autres, tres proches des réalités naturelles et de la pratique, doivent ensuite prendre le rélais pour mettre en valeur les resultats obtenus. Une telle succession de démarches apporte à L'exploitant L'outil dont il a besoin pour lutter efficacement contre es ennemis de ses cultures.

The establishment of a biometeorological model may either take account of biological phenomena in all their complexity or limit itself to practical considerations. In the first case, sophisticated data acquisition systems are required, for both meteorological and biological data, and a powerful computer is required to prove beyond doubt the statistical validity of any proposed relations. In the second case, fairly simple observations and equipment are sufficient. In spite of this opposition, both aspects are closely linked and complementary. The climate at a given site may vary considerably from one year to the next and sudden changes are quite common during control periods. Only a thorough study of the effects of meteorological incidents on organisms (host, predator or parasite) will show the possible limits to development. However, climatological studies also show the principal elements which must be observed and measured and the critical thresholds for each. Thus, well‐equipped laboratories can undertake the first task, leaving others closer to nature and practice to « digest » the results obtained and fulfil the second. This succession provides the means for effective pest control.
Monitoring Codling Moth (Cydia [Laspeyresia] pomonella L.) with Pheromone Traps1
Authors: CRANHAM J.E.
Published: April 2008

In England, codling moth is univoltine in most years and two, or even one, spray application will usually maintain the pest at very low levels. In the hot summers of 1975‐ 1976, moth numbers and the potential for damage to the fruit increased markedly. Many factors influence the numbers of moths caught in pheromone traps, and the relationship between trap catches and subsequent fruit damage has been very variable between orchards and between seasons. Nevertheless, the traps are reliable indicators of where sprays can be safely omitted and, alternatively, where a full spray programme is required. The effect of applying no sprays when catches remain below a threshold of five moths per trap per week is being widely tested. The rate of development of the first flight period varies markedly between orchards in a locality. Problems in the use of trap records to determine spray timing in individual orchards will be discussed.

En Angleterre, le carpocapse est le plus souvent univoltin et deux traitements, ou même un seul, suffisent à le maintenir a un niveau de population très bas. Durant les étés chauds de 1975 et 1976, le nombre de carpocapses a été beaucoup plus eleve, ce qui a considerablement augment les risques de dommages aux fruits.

De nombreux facteurs determinent le taux de capture dans les pièges à phéromones, ce qui entraine un manque de relation entre les captures et les déglts effectifs d'un verger et d'une saison a I'autre. Néanmoins, le piégeage permet de definir les périodes pendant lesquelles les traitements sont déconseilles ou, au contraire, indispensables. La suppression de tout traitement pour le cas ou les captures ne depasseraient pas un seuil de cinq individus par piege et par semaine est envisageée.

L'évolution du premier vol varie largement selon le verger. Ceci entraine des problemes d'extrapolation des résultats du piégeage pour la programmation des traitements.
Role of Population Quality in Forecasting for Plant Protection1
Authors: FRANZ J.M.
Published: April 2008

In order to assess the future abundance of a pest as the basis of the damage to be expected, actual numbers of individuals will not suffice. It is not only pre‐damage mortality of parasitized or diseased individuals that modifies threshold levels or the results of forecasting future losses. In addition, the quality of populations must also be considered, as it affects the expression of behaviour, reproduction and survival. This is illustrated by using two parameters: the effect of enzootic diseases and differences in yolk content of lepidopterous eggs, both of which have a strong influence on the validity of prognoses. The concluding recommendation is to find and to utilize qualitative differences between individuals as an aid to developing an improved method of forecasting insect development. Such progressive pest management would include forecasting the development of both pest and beneficial organisms and it would optimize means of proper manipulation.

Le dénombrement d'un ravageur ne suffit pas à la prévision de l'évolution future des populations de celui‐ci. A part la mortalité des insectes parasités ou malades, qui entraine la modification des seuils de tolérance et des prévisions de pertes, il faut tenir compte de L'effet de la qualityé des populations, dans la mesure ou celle‐ci influe sur le comportement, la reproduction et la survie des ravageurs. Deux paramétres exercant une influence importante de ce genre servent dillustration; il s'agit de L'effet des maladies enzootiques et des differences de teneur en vitellus des ceufs de lépidopteres. Il serait donc utile de recenser les differences qualitatives entre individus, ce qui pourrait servir à L'amélioration des previsions sur le developpement des insectes. Ceci est realisable aussi bien pour les insectes nuisibles que pour les auxiliaires et permet d'assurer une approche dans le sens du management.
Computer Mapping and Analysis of Nematode Distribution1
Authors: TAYLOR C.E. , BROWN D.J.F. , TOPHAM Pauline B.
Published: April 2008

A computer program was used to map the distribution of Longidorus and Xiphinema nematodes in the British Isles and to analyse relationships between distribution and vegetation or soil factors. Most of the records were obtained by taking soil samples from five vegetation types in each 10 km square of the Universal Transverse Mercator (UTM) maps of the British National Grid and the Irish National Grid. Nematodes were extracted from aliquots of each soil sample by a sieving and decanting technique, then killed by heat and fixed in triethanolamine formalin. A mapping program was written in FORTRAN to produce crude line‐printer maps for checking and for sets of standard 80‐column cards as input for the Biological Records Centre where the final maps were produced. Analysis of relationships between nematode occurrence and various biotic and abiotic factors was carried out using a standard computer program designed for social survey work and available at the Edinburgh Regional Computing Centre. The maps produced from survey data clearly defined the limits of distribution of Longidorus and Xiphinema species within the British Isles and analysis indicated factors such as soil type or vegetation which may be important in limiting their occurrence. It is suggested that similar survey and computer mapping procedures can be used to establish a European Survey of Plant Parasitic Nematodes.

Un programme sur ordinateur a permis d'établir des cartes de distribution des especès de Longidorus et Xiphinema dans les Iles britanniques et danalyser les relations qui existent entre la distribution des nematodes et les facteurs biotiques et édaphiques. Les données proviennent pour la plupart d'échantillons de sol preleves par reference a cinq types de vegetation dans chacun des carres de 10 km formant le réseau cartographique de la Grande‐Bretagne et de L'Irlande. Les nematodes sont extraits des echantillons de sol par une methode de tamisage, suivie d'une decantation; ils sont ensuite tues par la chaleur et fixes dans une solution de formaline‐triethanolamine. Un programme cartographique a ete etabli en FORTRAN afin d'obtenir des cartes brutes imprimées qui permettent des verifications et le transfert des donnees sur cartes à 80 colonnes qui alimentent le systeme du « Biological Records Centre » dont la tiche consistera a produire les cartes definitives. Lanalyse des relations entre la distribution des nematodes et divers facteurs biotiques et abiotiques a été réalisée par un programme normalisé, en usage pour les enquctes toxicologiques du Centre régional dinformatique d'Edimbourg. Les mêmes methodes pourraient être utilisees pour L'etablissement dune etude de la distribution des nematodes au niveau europeen.
Forecasting Crop Damage by Nematodes: Nematode Population Dynamics1
Authors: JONES F.G.W. , KEMPTON R.A.
Published: April 2008

Factors affecting the ease or difficulty of forecasting and modelling cyst, root‐ectoparasitic and soil surface nematodes are mentioned. To relate pre‐planting to post‐harvest populations of cyst nematodes, a version of the logistic curve is derived from first principles and modified to take account of the injury done to root systems as numbers increase, and of eggs carried over to the following year. Egg hatch, when potato or other crops are grown, appears to be independent of population density. So also does root invasion over the population densities encountered in field plots. In the absence of enemies, population density is determined by competition for feeding sites induced by females in the root system, and by the size of the root system. Population oscillations about the equilibrium point are affected mainly by the proportion of the population that fails to hatch and the damage to the root system. The process of model building and the parameters required are outlined. The model includes hypotheses relating to intraspecific (genetic) competition and interspecific competition. The limitations of models and the need to make them stochastic are discussed.

L'article fait état des possibilites et difficultés rencontrees dam la prévision et la modelisation des populations de nematodes a kystes, de nematodes ectoparasites des racines, et de nematodes de surface. Afin detablir la relation entre les populations de nematodes a kystes avant le semis et apres la recolte, il est recouru a la courbe logistique, derivee des principes fondamentaux. Celle‐ci se trouve modifiee afin de tenir compte des degits croissants subis par les racines en fonction de I'augmentation des populations et de la survie d'une partie des ceufs d'une annee a I'autre. L'eclosion des ceufs semble être independante de la densite des populations dans les champs de pommes de terre et de toute autre culture. Ceci s'applique egalement a I'invasion des racines, dans le cas des densites de populations observees dans les parcelles experimentales. En I'absence dennemis, la densite est determinee par la competition pour L'acces aux sites de nutrition que les femelles preparent dans les racines, et par L'importance du systeme radiculaire. Les ecarts de population observes a partir dun equilibre sont principalement dus a la proportion de la population non eclose et aux deggts subis par les racines. I1 est fait etat d'une modelisation, basee sur certains parametres essentiels. Le modele repose sur L'hypothese d'une concurrence intraspecifique (genetique) et interspecifique. Les limites des modeles sont considerees, ainsi que la necessite de passer a une approche stochastique.
The Forecasting System for Plant Protection in the USSR: Its Theory, Methods and Organization1
Authors: POLYAKOV I. Ya.
Published: April 2008

In the USSR, the system of forecasting the occurrence of crop pests and diseases consists of long‐term, yearly or seasonal forecasts, and a warning service. They allow for prophylactic plant protection to be adequately planned and organized both on a country‐wide and a regional scale. Theoretically, all kinds of forecasts are based on a knowledge of the population dynamics of pests. The criteria used to develop forecasts are the state of certain climatic and energetic factors during previous seasons, which determine the morphophysiological features of populations and the way they will react to the environment in the future. On this basis, mathematical formulae can be developed and the management of pest population dynamics can be planned. The main biological information required for forecasting is collected by the State Plant Protection Service. Data on climatic conditions and the state of crops are supplied by the Hydrometeorological Service. Methods of data collection, treatment and interpretation are developed by research institutes according to the accepted model of pest population dynamics.

En URSS, les previsions se font a long terme, a echeance d'une annee et sous forme d'avertissements saisonniers. La protection des plantes peut, de ce fait, etre planifiee a I'echelle nationale et regionale. En principe, toutes les previsions sont basees sur la connaissance de la dynamique des populations de ravageurs et maladies. Les criteres utilises pour la preparation de previsions comprennent le recours a une serie de facteurs climatiques et energetiques qui ont prevalu durant les saisons precedentes. Ceux‐ci determinent les caracteristiques morphophysiologiques des populations et la faGon dont elles vont repondre aux conditions de I'environnement. Ceci permet de developper des formules mathematiques de prevision et de planifier le management des populations des depredateurs. La plus grande partie des donnees necessaires a ces previsions sont recueillies par le Service de la protection des vegetaux. Les donnees sur le climat et sur la phenologie des cultures parviennent au Service hydrometeorologique, alors que les methodes de lutte sont developpees par les instituts de recherches, sur la base de modeles de la dynamique des populations.
A Warning System for Fruit Pests in Eastern Switzerland1
Authors: MANI E.
Published: April 2008

A warning system for fruit pests has been developed in eastern Switzerland during the past 25 years. A network of 30 observers is supervised by regional advisers. From spring until autumn, the advisers collect data on pest occurrence each week and transmit this by telephone to the Wadenswil station. Here, the information is summarized, interpreted (in discussion with the regional advisers) and condensed. This text is sent each week to subscribers, including advisory specialists of the state, of cooperative societies and of industry. Recommendations given by different agencies to growers have become highly coordinated by this system.

Methods used for assessing fruit pests include inspection of trees in spring and summer, inspection of twig samples in winter, pheromone traps for tortricids. Observers focus their attention on the main pests which often exceed the economic threshold, as well as on occasional pests that are easily overlooked by the grower.

The warning does not constitute an order to the grower as to when and how to spray; it is a short summary of the pest situation and an indication regarding what kind of inspections are necessary at the orchard level. This regular information gives more security to the grower about pest problems and helps him in making his own decisions. The warning system has been a main factor in reducing and stabilizing the application of insecticidal sprays in fruit growing.

Un systeme d'avertissement contre les ravageurs des arbres fruitiers a ete mis en place, puis ameliore en Suisse orientale au cours des 25 dernieres annees. Un reseau de 30 observateurs est supervise par des conseillers regionaux. Ceux‐ci recueillent des donnees sur la densite des ravageurs, chaque semaine du printemps a I'autornne, et transmettent celles‐ci par telephone a la Station de Wadenswil. Les donnees sont alors traitees en consultation avec les conseillers et les conclusions de I'etude sont envoyees chaque semaine aux abonnes, ainsi qu'aux conseillers gouvernementaux ou travaillant pour les cooperatives ou pour I'industrie. 11 en est resulte une harmonization importante des recommandations emises par toutes ces instances.

Les methodes utilisees pour les denombrements comprennent I'inspection des arbres au printemps et en ete, L'inspection dechantillons de branches en hiver et le recours au piegeage sexuel des tordeuses. Les observateurs concentrent leur attention sur les ravageurs principaux qui depassent souvent leurs seuils de tolerance economique ainsi que sur certains ravageurs occasionnels qui risquent d'etre negliges par les producteurs. Lavertissement ne comporte pas une recommandation precise sur la date et la methode de traitement. I1 resume plutbt la situation relative aux ravageurs et indique le type d'inspection qui est recommande dans les vergers. Le producteur qui reGoit ces informations regulierement prend ses propres decisions d'intervention avec plus d'assurance. Le systeme d'avertissement a permis de reduire et de stabiliser le nombre de traitements insecticides en arboriculture.
Developpement d'un système de prévison et de lutte contre le carpocapse (Laspeyresia pomonella L.) en Suisse romande: rôle du service regional d'avertissement et de L'arboriculture1
Authors: CHARMILLOT P.J.
Published: April 2008

La lutte contre le carpocapse repose sur un systéme de prévision basé sur des informations valables au niveau régional ainsi que sur des moyens de contrôle au niveau de la parcelle. Les services officiels fournissent des points de repère dans le cycle évolutif. lis indiquent les périodes durant lesquelles les différents contrôles doivent étre effectués par L'arboriculteur. L'outil principal de L'avertissement régional est la somme des températures moyennes supérieures à 10oC. Au niveau de la parcelle, 3 moyens d'avertissement sont utilisés: le piégeage sexuel, le contrôle des pénétrations et les relevés des bandes‐pièges. L'arboriculteur peut intervenir par une lutte au moment du dépassement du seuil de tolérance, ou par une lutte précoce pour éviter les traitements de seconde génération.

Control of codling moth depends on a forecasting system based on information at the regional level and on orchard inspections. The official services provide the reference points in the development cycle. They recommend the times at which the grower should make appropriate inspections. The main method for regional warning is the heat‐sum above 10oC. At the orchard level, three methods are used to provide warnings: pheromone trapping, inspection of penetration and collection of trapping strips. The grower can treat when tolerance thresholds are passed, or control at an early stage to avoid second generation treatments.
Early Warning System for Apple Pest Management in Canada1
Authors: TROTTIER R.
Published: April 2008

Since 1973, research has been carried out in eastern Canada to develop early pest warning systems for apple pest management programs. The development and standardization of effective monitoring techniques and biometeorological indices has permitted precise forecasting of critical events in the life cycle of the major pests. The formation of a computerized network which links, by Telex and Code‐a‐Phone, all the major apple growing regions in Ontario has permitted the implementation of the early warning system. Our system is based on a mini‐computer. Twice a week biological and weather information, from the different growing regions, is received at our computer center. Computer programs are executed and early warnings are returned on the same day. In this way apple growers are being advised in real‐time of the optimal dates for pesticide applications. As a result, most apple growers in Ontario have reduced pesticide applications by 40 to 50 %.

Depuis 1973, des travaux de recherche se poursuivent dans les stations federales de I'est du Canada afin de mettre en place un systeme de previsions phytosanitaires. Grice a I'etablissement de modeles biometeorologiques ainsi qu'a de nouvelles methodes de piegeage, il est maintenant possible de predire avec precision les stades critiques du developpement des principaux ravageurs. L'ordinateur est a la base de notre systeme de prevision. Deux fois par semaine I'information biologique et meteorologique provenant des regions pommiferes converge par telex au centre des donnees. De cette faqon il est possible d'aviser les pomiculteurs, d'une region donnee, des dates de traitements les plus favorables au succes de la lutte dirigee.