bluuebunny/crossref_metadata_2025 huggingface dataset:
Interleukin‐6 receptor superantagonist Sant7 inhibits TGF‐β‐induced proliferation of human lung fibroblasts
Authors: Gallelli L. , Falcone D. , Pelaia G. , Renda T. , Terracciano R. , Malara N. , Vatrella A. , Sanduzzi A. , D’Agostino B. , Rossi F. , Vancheri C. , Maselli R. , Marsico S. A. , Savino R.
Published: April 2008

Abstract.  Objectives: Both interleukin‐6 (IL‐6) and transforming growth factor‐β (TGF‐β) are crucially involved in fibrotic events that characterize interstitial lung diseases (ILD). Therefore, the aim of this study was to investigate in primary cultures of normal and fibrotic human lung fibroblasts (HLF), exposed to either IL‐6 or TGF‐β1, the effects on phosphorylation of mitogen‐activated protein kinases (MAPK) and cell growth of IL‐6 signalling inhibition, performed by the IL‐6 receptor superantagonist Sant7.Materials and methods: MAPK phosphorylation was detected by Western blotting, HLF viability and proliferation were evaluated using the trypan blue staining and the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay, respectively. Results: Sant7, at a concentration of 1 µg/mL, was capable of significantly inhibiting HLF proliferation and MAPK phosphorylation induced by cell exposure to IL‐6 (100 ng/mL) or TGF‐β1 (10 ng/mL), whose actions were more evident in fibrotic cells. Conclusions: These findings suggest that, in HLFs derived from patients with ILDs, the proliferative mechanisms activated by TGF‐β1 are at least in part mediated by an increased release of IL‐6, leading to phosphorylation‐dependent MAPK activation. Such preliminary findings may thus open new therapeutic perspectives for fibrogenic ILDs, based on inhibition of signal transduction pathways stimulated by the IL‐6 receptor.
Patterns in the abundance and distribution of ichneumonid parasitoids within and across habitat patches
Authors: FRASER SALLY E. M. , DYTHAM CALVIN , MAYHEW PETER J.
Published: April 2008

Abstract1. Knowing how species are distributed across a landscape can considerably aid the management of populations and species richness. Insect parasitoids constitute a large fraction of terrestrial biodiversity and help regulate other insect populations, but their ecology is poorly known at a landscape scale.

2. Using Malaise traps distributed first extensively and then intensively across woodland patches in an agricultural landscape, we tested whether four ichneumonid subfamilies display (i) a positive relationship between abundance and occupancy, (ii) a positive relationship between abundance in the extensive sample and abundance in the intensive sample, and (iii) aggregation across traps.

3. A positive relationship between abundance and occupancy was found across species in both samples, and was relatively strong. Abundance in the extensive samples was positively correlated with abundance in the intensive samples. On average, species were aggregated in both samples, although aggregation was not necessary for a positive abundance–occupancy relationship.

4. These results suggest that ichneumonid species can largely be classified on a continuum from widespread and locally abundant to localised and locally scarce. The former species allow the potential for pervasive natural control of host populations. The latter species, which constitute a substantial majority of the species list, will be vulnerable to extinction through both stochastic forces and widespread adverse forces such as climate change and habitat modification. However, the assessment of species’ status is likely to be facilitated by the positive abundance–occupancy relationship.

5. Species inventories for ichneumonids will be taxing because of the need to sample both intensively and extensively to detect rare species, which constitute the majority of species. However, it is possible to generalise species abundances across spatial scales and years, facilitating monitoring.
La situation réelle en matière d‘évaluation des pertes de récoltes
Authors: Strickland A.H.
Published: April 2008

Summaire

Après un bref exposé historique portant sur les 100 dernières annèes, il est fait état des trois éléments intervenant dans l'estimation des pertes de récoltes, à savoir: détection de la présence de l'organisme nuisible, mesure de l'incidence ou de l'intensité de ses attaques et évaluation des réactions de la plante‐hôte. Une justification objective des interventions antiparasitaires d'envergure est demandée par les milieux politiques et économiques, tandis que les recherches se poursuivent sur les possibilités d'assurer des gains de production par une lutte efficace; l'accent est mis sur l'importance des prévisions indiquant la nécessité de tels traitements. II importe de bien définir les buts des évaluations envisagées afin de profiter au maximum des économies que permettent de réaliser les méthodes modernes de statistique.
Resistance as a Means of Control of the Potato Root Eelworm
Authors: Huijsman C.A.
Published: April 2008

A survey of the resistance of wild potatoes to the potato root eelworm and the use made of this property in potato‐breeding is presented. Several biotypes of this parasite have been found to exist. The use of resistant varieties in the control of the potato root eelworm, in connection with other methods of control (crop rotation and soil disinfestation), is discussed.
Some Aspects of Chemical Control of Soil‐borne Pathogens
Authors: Besemer A.F.H.
Published: April 2008

The effect of a soil fumigant on soil‐borne pests and pathogens depends largely on a sufficient distribution through the top soil and the availability of the fumigant or the biologically active degradation products in the water phase. Nearly all the fumigants are dispersed in the soil mainly in the vapour phase and therefore the amount of air between the soil particles is very important. Consequently on light soils it is relatively easy to obtain an efficient control, but on heavy or wet soils and on soil types with a high humus content it is rather difficult to get reliable results. The concentration of the fumigant in the upper few cm. of the soil is often insufficient to get good control after injection of the material at 15–20 cm. depth. The effect may be improved by using a plastic cover or a «split plot» application.

The elimination of most of the fumigant, to avoid a phytotoxic effect is a cause for concern on wet soils and on soil types with a high organic content. Factors influencing the decrease of the fumigant residue in the soil are discussed. The soil fumigant application gives rise to important changes in the whole ecosystem in the soil. Information on the influence on non‐target organisms is scarce. The application of dichloropropene and of chloropicrin may lead to a noticeable effect on the nitrificating bacteria.

The soil application of fumigants may give rise to residues in plants of the parent chemical or, to a larger extent, to residues of metabolites e.g. Br‐ after soil disinfection with Br‐ containing fumigants such as methylbromide, EDB1), etc. The enrichment of the soil with Br‐ may cause phytotoxic effects on susceptible crops such as carnations. The fate of the metabolites arising from dichloropropene and related compounds has not been fully clarified.
Soil‐borne Pests and Pathogens Associated with Imported Plants, with Special Reference to Nematodes
Authors: Southey J.F. , Aitkenhead P.
Published: April 2008

The assessment of phytosanitary risks from imported soil entails recovery or assay of soil‐borne organisms, determination of pathogenicity and consideration of potential distribution as affected by environmental factors. Results are presented of examinations of soil from imported plants for nematodes and other pests. Nematodes were much more abundant than other pest groups. Plant‐parasitic nematodes were more common in natural soils than in potting composts, and non‐indigenous species were apparently more frequent from non‐European than European sources. The chief nematode hazards for northern European countries may be from new «pathotypes» of Heterodera species and ectoparasitic dorylaimid genera that include virus vectors. Nematodes and other organisms from tropical areas can become glasshouse pests in cooler climates.
Quarantine Aspects of the Epidemiology of Soil‐borne Pathogens
Authors: Kuiper K. , Boerema G.H.
Published: April 2008

For plant quarantine activities, more biological information on diseases in crops and natural vegetation along with more co‐operation are needed. Some phenomena, and results of studies on distribution and occurrence of fungi and nematodes are given in order to stress this necessity.
Recent Advances in the Bio‐ecology of Ceratitis capitata Wied. in Turkey
Authors: Tuncyurek M.
Published: April 2008

Since 1960, many studies on Ceratitis capitata Wied. have been carried out by entomologists in Turkey. A considerable number of host‐fruits were recorded. In 1961 the damage of C. capitata was recorded at 6.1 ‐ 7.8% in the western parts of the country and at 3.5 ‐ 6.2% in 1961–1965, in the south. The treatment period for controlling this pest has been determined by field observations in both western and southern Turkey. The population density of the fly in the field is shown.
Phenomena of Antagonism in Cultivated Soil
Authors: Zogg H.
Published: April 2008

Experience shows that yields ate normal if crop rotation is practised sufficiently. The case of Ophiobolus graminis Sacc. is studied in particular and it appears that after 2 or more years of the successive cultivation of winter wheat this fungus has accumulated to such an extent that the crop decreases to 50, 30 or even 10% depending on the weather conditions at that time. With sufficient crop rotation, the parasite is eliminated, within a certain time, by the antagonistic soil microflora. Methods of evaluating the impact of different species or groups on O. graminis are discussed and also the so‐called “decline” effect, according to which the accumulation of the pathogenic fungus responsible for losses in a continuous cultivation of the same crop is followed, after several years, by a depletion of the pathogen.
Problems in Monocultures
Authors: Kupers L.J.P.
Published: April 2008

In the author's opinion, modern farm management techniques compel a critical evaluation of established concepts of the use of rotations in arable farming as rapid changes have put many formerly accepted reasons for their use in doubt. From literature, examples are cited which show clearly that monocultures of cereals, or cereals grown in narrow rotations, can attain economically acceptable yield levels. From his own personal work in this field the author cites results which demonstrate that with adequate husbandry techniques, even monocultures of wheat can reach normal yields. In the conclusion, the need for close co‐operation between specialists in order to obtain results, which can be applied to a wider scale of farming conditions, is stressed.
Impact of Research on Grain Storage Practices in Canada1
Authors: Watters F.L.
Published: April 2008

Cold winters, a well‐developed bulk handling system, regular inspections of elevator premises, stored grain and cargo ships, and the application of pest control measures when necessary, minimize storage problems in Canadian grain. Research has played an important role in identifying the organisms and circumstances which cause infestations of stored grain and in developing and evaluating environmental, physical and chemical methods for preventing and controlling infestations. This information enables commercial grain organizations and government regulatory agencies to provide high quality grain for domestic consumption and export markets.
Remote Sensing Applications to Agricultural Monitoring1
Authors: Chiang H.C. , Meyer M.P.
Published: April 2008

The development of detection of insect infestations from aircraft was reviewed. It started with visual observation and written records, and developed to photographic recording with color films and infrared films, then to enhancement of photographic images.

Aerial photography was used to detect simulated insect defoliation in corn fields. Several guide‐lines were established: defoliation on top of plant was easily detected while that on the base of plant was less so; aero infrared film with a Wratten 89B filter gave the best results, morning flight at the scale of 1: 15,840 is to be recommended, and row direction, plant growth stage and time elapse since defoliation were not important factors.

The multiple uses of aerial photography in agricultural monitoring were proposed, and the research needed to implement the proposed scheme was outlined.

The potential and limitations of remote sensing from spacecraft such as the Earth Resources Technology Satellite and the SKYLAB were discussed.
Leptohylemyia coarctata (Fall.) ‐ Integrated Control and the Use of Economic Thresholds1
Authors: Bardner R.
Published: April 2008

Yields of crops attacked by wheat bulb fly can be predicted, but this cannot be done until much damage has occurred. In this situation the concept of economic thresholds is of limited use. It is much more important to be able to predict the likelihood of infestations as this enables the correct use to be made of prophylactic seed dressings. This and other approaches to integrated control are discussed.
La météorologie agricole au service des programmes de lutte intégrée 1)
Authors: Mueller W.
Published: April 2008

Sommaire

Les méthodes biomété orologiques qui intéressent les biologistes appelé s à développer des systèmes de lutte intégrée se distinguent nettement de la climatologie traditionnelle de l'abri. D'une façon générale, les différences peuvent se résumer comme suit: –les investigations se font essentiellement à l' échelle microclimatique; –les instruments sont très élaborés et particulièrement adaptés au but recherché; –l'établissement du réseau d'observations et les périodes d'études dependent des exigences biologiques; –la durée des périodes d'observation est limitée et la densité du réseau climatologique relativement faible grâce au recours à l'échantillonnage représentatif.

L'interprétation des résultats biométéorologiques est en général difficile puisqu'il y a souvent superposition de deux ou d'un nombre plus élevé de facteurs. II est done prudent d'inclure également, dans l'appréciation générale, les données de laboratoire et de s'efforcer de remplacer les données plus ou moins empiriques par des fonctions précises. Cette approche est proposée sous la forme d'une étude quantitative du bilan énergétique et hydrique des ravageurs. On peut ainsi obtenir des résultats de portée étendue, reposant sur des données physiques, d'une part, et des renseignements quantitatifs, d'autre part.

Un certain nombre de facteurs simples ou composés tels que le vent et la faculté de refroidissement sont à considérer dans les études biométéorologiques puisqu'ils contribuent à caractériser, et partant, à prévoir le comportement des espèces (par exemple l'activité de vol du carpocapse des pommes).

En définissant des « types de temps » favorables à l'activité d'un ravageur, il serait possible de prévoir le comportement de l'espèce en question.

Enfin, l' étude conjointe des vues prises par satellites à l'aide de films à infrarouge, thermiquement sensibles, et des observations biométéorologiques faites au sol apportera sur le plan macro‐ et méso‐climatique des éléments eminemment utiles au développement de la lutte intégrée.
Current Status of Integrated Control of Citrus Pests in Israel1)
Authors: Rosen D.
Published: April 2008

Following the spectacular biological control of the Florida ted scale, an effective program of integrated control was developed on citrus in Israel. In recent years, a gradual increase of various pests has brought about a marked increase in the amounts of non‐selective pesticides applied on citrus, which has in turn triggered still heavier pest resurgences. Intensive efforts are now being made to break that vicious cycle and restore the upset natural balance in the citrus eco‐system. A vigorous biological control program has been embarked upon. The prospects for successful integrated control are very good, especially if more realistic tolerances for insect damage on citrus fruit are adopted.
Cost‐Benefit Analysis of Crop Storage Improvements: A South Indian Pilot Study1)
Authors: Lipton M. , Cook I. , Nair N.
Published: April 2008

Storage research, especially at small‐farm level, makes too little impact on policy, largely for want of evidence that the benefits of grain savings – especially to the poor and hungry – justify the costs of improved structures. The paper describes a pilot survey of the costs and benefits of alternative means of paddy storage in two South Indian villages. Preliminary results suggest that subsequent, ongoing work in a larger sample of villages will justify substantial outlays on improved stores for small farmers and even landless labourers.
Yield Trends during Take‐all Decline in Spring Barley and Wheat Grown Continuously1
Authors: Shipton P.J.
Published: April 2008

The effects of take‐all, nitrogen and cropping sequence on grain yield were compared for spring barley and spring wheat grown in extended monoculture. Initial crops showed least take‐all and maximum yields. Yields fell to a minimum more rapidly in wheat than in barley while the take‐all intensity increased to a maximum; take‐all decline occurred and yields improved from the 4th and 5th years respectively. Without nitrogen, yields were at their lowest level; application of nitrogen increased yields considerably with responses in proportion to the rate applied. At optimum rates, yield losses were 33% for wheat and 11% for barley with maximum disease intensity but only 9% and 3% respectively with take‐all decline. Potential maximum yields in the absence of take‐all were calculated to be greater with barley than with wheat.
Studies on the Fecundity of Acarid Mites (Acarina: Acaridae)1
Authors: Boczek J. , Czajkowska B.
Published: April 2008

The effect of food on fecundity and its distribution during the life of Acarus siro L. was studied. In addition, the effect of repeated matings, of age of females and males, of parental age and of sex ratio on the fecundity of Tyrophagus putrescentiae (Schr.) was studied.

Nutrition affects the total fecundity and its distribution in A. siro. The highest fecundity of T. putrescentiae females occurred when mating occurred more than once a week. The fecundity of ageing virgin females decreases gradually with delays in the time of the first mating. The effect of male's age is not significant until the age of 60 days onwards. Females descending from 100‐day‐old parents showed 25% lower fecundity than females from young parents.

Density of males above the sex ratio 1:1 diminishes the fecundity of females molested by males. The higher the number of the males in the cage per female, the lower their fecundity.
The Detection of Latent Ring Rot (Corynebacterium sepedonicum [Spiek. et Kotth.] Skapt. et Burks.) in Potato Stocks1
Authors: Lelliott R.A. , Sellar P.W.
Published: April 2008

Very low numbers of Corynebacterium sepedonicum (Spiek. et Kotth.) Skapt et Burkh. in potato tubers can be detected by inoculating the bacterial fraction separated from cores (including the vascular tissue) taken from the heel end of tubers into young eggplants (Solanum melanogena). One tuber with simulated latent ring rot infection could be detected readily when mixed with 99 uninfected tubers.
Verticillium Wilt of Apricots
Authors: Popushoi I.S.
Published: April 2008

Following a brief introduction on the economic importance and reported causes of apricot dieback, the author describes the symptoms, both external and internal, induced by Verticillium dahliae Kleb., the wide host‐range of this fungus, and its diagnostic features on various culture media. Verticillium wilt characteristically affects vigorously growing trees, the latter being most susceptible from 3 to 10 years old. There is either a sudden wilting or a progressive dieback; necrosis is clearly visible and vessels become occluded. Optimum mycelial growth occurs at 22–24°C (range 9–33 °C) and at pH 6.1–6.85 (range 3–3.5–12). Factors affecting growth of the pathogen, particularly the role of ascorbic acid content of fruit trees, are discussed. Epidemiology and control are also reviewed. There are no means for curing diseased trees; breeding offers the best chance for control.
Plant Damage by Bank Voles (Clethrionomys glareolus [Schreber]) and Related Species in Europe1
Authors: Hansson L. , Zejda J.
Published: April 2008

A survey of the ecological adaptations of the bank vole, Clethrionomys glareolus (Schreber), indicates that this species is a potential pest, particularly to forest tree seeds and bark. Observations from most parts of Europe show clear cases of damage to seeds, young shoots and buds and bark of young trees above the snow level. Worst losses appear in central and eastern Europe. The bank vole may also attack a few year old seedlings (either bark or complete consumption). Widespread seedling attacks, which are economically very important in some countries, have, however, not been definitely proven for this species. In northern Europe, the bank vole may also cause damage to hay in barns.

Bank vole populations show greatest fluctuations in eastern and northern Europe. The cycle length is variable. Damage (except, possibly, seed consumption) appears mainly during or just after the appearance of peak populations. Baits with zinc phosphide seem to be the most efficient control method. A number of other preparations have been tried more or less successfully.

In summary, knowledge of the economic importance of the bank vole is very restricted. Specific studies are suggested for improving such an evaluation.
Usefulness of Stress Indicators in Forecasting Population Trends in Microtus arvalis (Pallas)1
Authors: Hamar M. , Tuta Al. , Petrescu Anca , Babes Liliana
Published: April 2008

The appearance of a stress condition in Microtus arvalis (Pallas) populations was established on the basis of histochemical analyses and correlated with population dynamics. It was found that stress appears only during invasions, i.e. when crop damage has already occurred.

Commonly, the population crash occurs 30 to 50 days after the appearance of stress. It is concluded that stress indices can neither be used for warnings nor for long‐term forecasts of outbreaks.
Studies of Variations in Weight and Volume of Internal Organs of Microtus agrestis (L.) and their Possible Relation to Fluctuations in Population Density1
Authors: Giege B.
Published: April 2008

This paper discusses the possibility of measuring the cumulative effect upon voles of measurable and immeasurable, endogenous and exogenous stress factors. Variations in certain internal organs (adrenals, thymus, spleen, brown adipose tissue) were studied in 2 populations of Microtus agrestis (L.) in Sweden.

Both these populations ended in a crash, but after a different period of time. Variations in the internal organs observed during certain investigation periods up to the crash are discussed. Weight of adrenals appeared to be dependent on population density. Spleen hypertrophy did not seem to appear untU stress reached a certain level and after that was more or less persistent. Thus, the spleen might well be a good indicator of the cumulative effect of exogenous and endogenous stress. The amount of axillary brown adipose tissue could, to a certain extent, be a measure of mean ambient temperature, and, perhaps, could also give information on incipient stress situations. The investigation indicated that there are reasons to assume correlation exists between spleen hypertrophy in voles and their damage to plants.
Evaluation of Rodent Depredations to Crops and Stored Products1
Authors: Jackson W.B.
Published: April 2008

Estimates of food losses to rodents vary widely. In most cases, such estimates are not statistically defensible. Adequate sampling techniques have only been developed for a few crops and a few situations. Often, estimates have been related to rodent numbers, which have not been validly determined.

Environmental management is basic to rodent control, both in terms of growing crops and stored products. Many aspects of intermediate technology have important applications to this need.

Needs relate to better understanding of rodent ecology, adequate assessment of damages, training of specialists in management of vertebrate pests, and use and development of appropriate technologies.
Methods of Laboratory Toxicological Investigations on the Common Vole (Microtus arvalis [Pallas])1
Authors: Nikodémusz E. , Nechay G.
Published: April 2008

This paper reports on some laboratory methods for evaluating the toxicity of rodenticides to the common vole. Test conditions including the experimental animals used, their housing, feeding and handling (measuring body weight, marking of the individuals, route of administering the toxicant), test materials and observations are presented.

New toxicants were screened simultaneously on white rats and on voles. For each compound, the following data were determined: a) the acute (single dose) approximate LD50 (= ALD50), b) the acute (single dose) LD50, as well as the multiple dose toxicity for anticoagulants, c) the approximate 5‐day LD50 and d) the 5‐day LD50.

For the determination of a) and c), about 6 animals were used. The LD50 values were determined by giving 6–8 doses to each of 10 rats and 4 doses to each of 4–6 voles.

A brief report is given on the determination of the joint toxic action of the 2 chemicals.

Rodenticidal formulations were tested on voles in various no‐choice and choice feeding tests. No‐choice tests with compounds having an acute toxicity were carried out for 24 h, those with anticoagulants for 5 × 24 h and those with narcotics for 2 × 24 h. The corresponding periods for choice tests were 2 × 24 h, 5 × 24 h and 4 × 24 h, respectively.

Preference and repellency tests were also carried out.

The stability of a rodenticide in baits exposed to weather, as well as the effectiveness of fumigants on solid carriers were investigated under simulated environmental conditions.
New Rodenticides Against Anticoagulant‐resistant Rats and Mice1
Authors: Lund M.
Published: April 2008

The comparatively few newly developed rodenticides are mentioned, and their effectiveness against warfarin‐resistant rats and mice is discussed. Two compounds, an acute poison and an anticoagulant, seem to be more promising than others.
Methods of Monitoring Rat Infestations, and Approval Schemes for City‐wide Deratization Operations1
Authors: Gacs F. , Herczeg T. , Papocsi L. , Elek S.
Published: April 2008

An account is given of the program for deratization of Budapest (city and suburbs) and the maintenance of a rat‐free state. A single contractor, the Babolna Disinfecting Station, was entrusted with carrying out the 3 phases of the program, which consisted of large‐scale poisoning of rats with Racumin 57 (3 [α‐tetralyl] ‐4‐hydroxycoumarin), in houses, factories and sewers. Use was made of the mass media to encourage the public to help in reporting infestation foci. Between January 1971 and December 1972, rat infestation levels were reduced from 43% to 0.065%. Continued vigilance has ensured that this acceptably low level has been maintained. There were no indications of resistance to the rodenticide used developing.
Recent Progress in Breeding for Fireblight Resistance in Apples and Pears in North America1
Authors: ALDWINCKLE H. S. , ZWET T. VAN DER
Published: April 2008

Resistance in apple is evaluated by needle–inoculation of succulent shoot tips with 106–107 cells of a virulent isolate of Erwinia amylovora (Burr.) Winslow et al. (the incitant of fireblight) and measurement of the resulting cortical lesion when extension is complete. Data are now available on practically all commercial cultivars, some of which have a useful level of resistance. Some newer cultivars, particularly those with resistance to scab (Venluria inaequalis [Cooke] Wint.) derived from Malus floribunda, have good resistance to E. amylovora. A very high level of resistance is present in Asiatic Malus species, including M. x robusta, M. x sublo–bata, M. x atrosanguinea, and M. prunifolia, and in the North American species M. fusca. This type of resistance appears to be inherited polygenically, and because of its detectability in young seedlings can be used conveniently in breeding.

Objectives of pear breeding programs are aimed at developing superior fruit quality combined with resistance to fireblight, psylla, and Fabraea leaf spot. Many high quality cultivars of Pyrus communis are extremely susceptible to E. amylovora and sensitivity appears to be controlled by a dominant gene Se. A high level of resistance is present in P. ussuriensis but varies considerably between clonal selections of other Pyrus species. Pear seedlings from controlled pollinations are artificially inoculated in the glasshouse with a similar bacterial suspension as used for apples, and only the most resistant ones are selected and planted in the field for future evaluation. In Beltsville, heritability studies of crosses between non–sensitive parents have indicated that selection for resistance within progenies results in a high degree of genetic gain. Interspecific hybridization has an advantage over P. communis crosses mainly when insect or fungus resistance is required.
Introduction to Weed Problems 1
Authors: FRYER J.D.
Published: April 2008

I have approached the very wide topic of this paper by outlining the modern concept of weediness as traced from the beginnings of agriculture and then giving examples of some important present day weed problems from various parts of the world. Weeds have no place in nature and are essentially a reflection of the environment and of man's activities and desires. When these change, the weed flora responds and weed control methods may have to be modified. In developed agricultural systems, weed control has been revolutionised by herbicides which have also allowed major advances in methods of crop production and land and water management. As a result some classical weed species are no longer important whilst hitherto unimportant species have emerged as major problems. In many parts of the world there are obstacles to the introduction of chemical weed control techniques, and weed problems and control methods are much the same as they have always been. With the increasing world population and the need to provide more food, intensification of agriculture is inevitable. If weed control is not to be a limiting factor, more recognition and support must be given to weed science as an essential discipline of agricultural research.
A Concept of Pest Risk Analysis
Authors: KAHN R.P.
Published: April 2008

A pest risk analysis curve on a graph is used to present diagramatically 1) the concept of pest risk analysis, and 2) the interaction of biological, economical, social, and political factors with quarantine policies, regulations, or decisions. The culmination of these regulatory activities often leads to a decision about the entry status of a wide spectrum of imported “items”. While the concept pertains to animal as well as plant quarantine matters, this paper concentrates on plant quarantine. Most of the examples presented relate specifically to the pest risk associated with importing plants or plant parts for propagation. Some of the examples presented have wide application in international quarantine circles while others relate only to the United States.

The method of illustrating pest risk analysis as a curve should be useful in effectively communicating quarantine philosophy, principles, policies, and decisions not only to the commercial, lay, and scientific public, but to plant quarantine officers. For within–house quarantine activities, the diagrams may be useful in training, explaining assignments or responsibilities to officers, determining priorities or planning budgets, and as a means for emphasizing the biological aspects of decisions about entry status of imported items.
The Place of Multiple Regression Analysis in Modern Approaches to Disease Control1)
Authors: ROYLE D.J. , Burr D.J.
Published: April 2008

In this paper multiple regression models are compared with fundamental models in the context of the plant disease system. The value of the regression technique for analysing the pathogen–host–environment complex and for prediction is discussed. Although there are limitations to the use and interpretation of multiple regression equations, their underlying simplicity can be of advantage for the solution of many practical problems in disease management. Despite the empirical nature of multiple regression, it can be used to advantage in the construction of hybrid models of the deductive–inductive type which combine the summary of experience with the fundamental principles of disease mechanisms.
Predator–prey Systems with Mites1)
Authors: RABBINGE R.
Published: April 2008

Population models of fruit tree red spider mite and predatory mite are given, which are used to explain the regulation of spider mites by predatory mites and may be used to manage spider mite systems in apple orchards.

The models are based on extensive experimental knowledge of the bionomics of prey and predator. A detailed analysis of the prey–predator relations on the individual level paved the way for the development of prey–predator models on the population level. These models, based on the state variable approach, simulate the population fluctuations: of prey and predator in dependence of the changing abiotic factors during the season using time steps of a quarter of an hour and trace all state variables, as the number of eggs, larvae, adult females and gut content of the adult female predator. Verification of the models at different levels of integration showed good agreement between model output and the results of independent experiments, and this enabled a sensitivity analysis with the model. This sensitivity analysis showed the relative importance of different factors, so that management strategies to achieve tolerable prey–predator levels throughout the year may be developed.
Lutte biologique contre Eurygaster integriceps
Authors: VOEGELÉ J.
Published: April 2008

Un nombre important d'organismes vivants limitent, dans les conditions naturelles, les pullulations d'Eurygaster integriceps. L'inventaire exhaustif de ces auxiliaires reste généralement à faire, d'autant qu'il peut exister pour une espèce donnée des populations plus ou moins bien adaptées à cet hôte ou à des conditions écologiques données. Le choix étant fait, il reste à multiplier ces auxiliaires en très grand nombre. Cette production de masse peut être imaginée en recueillant des hôtes dans la nature, à partir d'hôtes de substitution vivants produits en laboratoire ou a partir de milieux synthétiques. II reste ensuite à conditionner ces auxiliares pour leur faire jouer leur fonction en temps opportun et pendant une durée convenable. La date et la décision de traitement dépendent de la détermination d'un seuil d'intervention. La distribution des parasites sur le champ est également à considérer et il y a lieu de rechercher un contrôle d'efficacité suffisamment sensible. Le renforcement des potentialités des auxiliaires doit également être examiné sur le plan de l'aménagement du milieu et sur celui d'une continuité de leur action dans le temps. Une telle lutte est finalement à concevoir dans un ensemble de mesures beaucoup plus larges qui constitue ce que l'on appelle communément la lutte intégrée.
Assessing Risks from Exotic Pests1
Authors: BAKER C.R.B.
Published: April 2008

Detailed assessment of the potential of an alien species to become a pest when introduced into a new area requires a comprehensive knowledge of the biology of that species. In the absence of such knowledge, species can be classified for temperate areas into one of four categories of risk on the basis of capacity for survival in similar climates and presence of host plants outdoors or under glass. The categories are: 1) potential outdoor pests, 2) potential glasshouse pests, 3) species that have outdoor hosts but are unlikely to become pests on them unless they adapt genetically (no hosts under glass), and 4) species that have no host plants outdoors or under glass, or are incapable of prolonged survival outdoors. Some aspects of the more detailed assessment of better known species are suitable for computer simulation modelling. The features of a phenological model currently being developed in England are briefly described. Estimates of the benefits derived from excluding a particular alien pest can be obtained from the cost of the additional annual control measures likely to be required if the pest were to be introduced. Estimates of factors such as crop losses, environmental problems and increased research and advisory work must be added to obtain a range of costs for years when pest populations are likely to be ← high →, ← normal → and ← low →. Costs of excluding the pest must include cost to government (staff costs, eradication measures, publicity etc.) and costs to industry. The resulting comparison of benefit with cost can aid decisions on the design and enforcement of phytosanitary regulations.
Potential Pathogens on Native and Exotic Conifers grown in Northern Europe1
Authors: YDE‐ANDERSEN A.
Published: April 2008

The article reviews the principal exotic diseases of conifers and the means by which they may be introduced into Europe. There is a need for agreement between theorganizations concerned (EPPO, EEC and national plant protection services) on the diseases which merit specific mention in regulations and off the measures to be adopted to prevent their introduction.
Exotic Virus and Virus‐like Diseases of Fruit Trees1
Authors: DUNEZ J.
Published: April 2008

According to the results of enquiries by the ISHS Working Group on fruit‐tree virus diseases, about 40 of these could be considered as exotic for the EPPO area. In fact, most are probably due to the same pathogens and no more than 12 exotic diseases of some economic importance exist. Those which are described here are, with a few exceptions, those reported in the EPPO Al list and in the EEC directives. Some are associated with mycoplasma‐like organisms (X disease, peach rosette, peach yellows, little peach), others with rickettsia‐like bacteria (peach phony, plum leaf scald), others with viruses (peach yellow bud mosaic, prunus stem pitting, apple union necrosis, cherry rasp leaf, flat apple, plum line pattern) and some, at last, are of unknown origin (peach mosaic). Most of these diseases show a natural spread, are able to infect many different species and would find, in the EPPO area, favourable conditions to settle and spread. Avoiding introduction of exotic diseases requires that the fruit‐tree growing countries, and especially those which have recently developed their fruit‐tree industry, should complete an inventory of the viruses present. ISHS has been struggling over recent years to standardize indexing methods and to arrive at better and more uniform international virus testing. The tremendous progress recently observed in the field of indexing now allows a contamination to be detected within weeks or even hours and consequently should help avoid or limit the introduction of new pathogens.
Modern Developments in Fungicide Use on Cereals1
Authors: FEHRMANN H.
Published: April 2008

The control of the main pathogens of cereals by fungicide sprays is reviewed, with reference to several new and promising fungicides. New fungicide mixtures are also available to replace mercury as a seed treatment. The risks of fungicide resistance are briefly considered. One side‐effect of fungicide use may be in influencing the incidence of minor pathogens, possibly through interaction with the phylloplane microflora. Fungicide use in cereals should be determined by systems of fungicide management currently being developed.
Unexpected Effects of Fungicides on Cereal Yields1
Authors: COOK R.J.
Published: April 2008

Field experiments with barley have generally shown a good relationship between disease and yield. However, in some experiments the yield response is greater than would be expected from the level of disease. In contrast, other trials have shown a reduction of yield following applications of tridemorph to spring barley. On winter wheat, trials in Germany have shown a poor relationship between disease incidence and yield following application of carbendazim or captafol at GS 30–31. About 10 96 of these responses were negative, although there was an average yield increase of 2–3 %. Similarly, in a series of trials in Britain an average yield increase of 3 % was not related to disease level. In these trials about 25 % of results showed no increase in yield. The carbendazim fungicides, and also certain others, have some cytokinin‐like activity and it is possible that this is related to extended green leaf survival. Other interactions with host‐cell chemistry can be envisaged. Fungicides also influence stability of the leaf microflora. By this effect they may favour diseases such as Typhula and Rhizoclonia, or else suppress secondary pathogens (Alternaria, Cladosporium) at the end of the season.
The Effect of Environment on Survival and Hatching of Heterodera avenae1
Authors: Meagher J.W.
Published: April 2008

Eggs within cysts of Heterodera avenae are able to survive long periods of desiccation and can be held for several years at 5oC when stored at low relative humidity. While this provides an excellent means of storing the nematode for use in laboratory experiments, field experiments show that desiccated eggs are readily dispersed by wind. Tolerance to desiccation is similar in free and encysted eggs, which hatch at the same rate. When eggs are desiccated, water is withdrawn from the larva within the egg shell. If cysts are exposed to conditions favouring eclosion, subsequent desiccation reduces egg viability and larval emergence. The importance of defining pre‐test conditions in survival studies is emphasized, and differences in the physiological state of eggs may explain different observations in Australian and European studies.
Population Dynamics and Control of Heterodera avenae ‐A Review with some Original Results1
Authors: Andersson S.
Published: April 2008

Control of Heterodera avenae should largely aim to keep densities below tolerance limits at sowing‐time (in spring oats < 1 egg/g soil, in susceptible barley < 3 eggs/g soil; spring wheat is only slightly less sensitive than oats, autumn‐sown cereals are more tolerant than spring‐sown ones). To obtain this, knowledge of population dynamics is important. Essential items in population dynamics are the host properties of different plants (characterized by two factors which do not always covary: maximum rate of multiplication and equilibrium density of the nematode), population decline of the nematode under fallow and non‐hosts and the external factors influencing these characteristics. For cereals the following host efficiency order is found: winter oats (best), spring oats, spring wheat, spring barley, winter wheat, rye. Winter barley may be close to spring barley, and maize is a bad host. Grasses are generally less good hosts than cereals and usually cause high and moderate densities of H. avenae to decline. However, especially in first‐year leys, rather high equilibrium densities may sometimes be maintained. Host properties of plants vary between sites and years and also relations between hosts may change. Populations decline under fallow, non‐hosts and resistant cereals, usually in the order of 70–85 96 annually. H. avenae populations are favoured by lighter soils and heavier soils with a proper structure and also by good plant nutrient conditions. Soil moisture in interaction with temperature influences population dynamics in a complex way, in which natural enemies of the nematodes may also be involved, not least certain fungi. In many fields these may keep nematode populations at harmless levels. Traditional control measures like proper crop rotations can only be used to a limited extent. The most promising approach for controlling H. avenae is an appropriate use of resistant cultivars, of which barley cultivars are also tolerant, while oat cultivars are usually very sensitive. Biological control has hitherto not been used actively. Chemical control is profitable in Australia but not under European conditions. Farmers should check the need for control through soil sample investigations or by other means.
The Decline of Heterodera avenae Populations1
Authors: Kerry B.R.
Published: April 2008

Populations of the cereal cyst nematode fail to multiply in many soils in Europe and farmers are able to grow susceptible crops intensively on infested land. Similar numbers of females develop on roots in summer in soils where numbers of the nematode increase or decline. Two fungi, Nematophthora gynophila and Verticillium chlamydosporium parasitize females on roots, prevent cyst formation, decrease fecundity, and limit nematode numbers. Formalin (38 % formaldehyde) soil drenches at 3000 1/ha reduce the activity of these fungi and populations of the nematode increase, N. gynophila is an Oomycete which infects by motile zoospores whose activity is decreased when summer rainfall is light whereas V. chlamydosporium is much less affected by soil moisture. The decline of Heterodera avenae populations is associated with large numbers of spores in soil. At present it is not possible to control the nematode by introducing these fungi into soils where they are few or absent.
Meteorological Forecasts and Other Services for Agriculture and Plant Protection1
Authors: HRBEK J.
Published: April 2008

A brief outline is given of the meteorological services for agriculture and plant protection and of the present state and future development of meteorological forecasts for farmers.
Modifications of Meteorological Elements within Winter Wheat Canopies1
Authors: MÜLLER W.
Published: April 2008

The importance of measurements in situ within crops is demonstrated. The purpose is to know the different conversion factors between meteorological screen values and the values within the canopy. Canopy effects have been shown on light penetration, temperature regime, interception of precipitation and duration of leaf wetness. The reference station was Ihinger Hof, near Stuttgart (FRG), for the period 1978–1981.
Utilisation en temps réel des relevés du système automatique suisse d'acquisition de données météorologiques dans la lutte contre le mildiou de la pomme de terre1
Authors: PRIMAULT B.
Published: April 2008

Partant du modèle allemand « PHYTOPROG », on a établi un programme qui utilise directement, c'est‐à‐dire en temps réel, les relevés horaires provenant du système automatique suisse d'acquisition de données météorologiques ANETZ. Comme le veut le modèle retenu, l'ordinateur calcule chaque jour l'indice correspondant aux 7 jours précédents. On tient ainsi régulièrement compte des périodes critiques, quelles que soient leur longueur ou leur place dans la semaine. Les premières expériences faites ont montré la nécessité d'adapter le modèle primitif aux conditions suisses, adaptation qui a fait ses preuves. L'utilisateur reçoit automatiquement par télex la liste des indices calculés. A lui d'effectuer la somme depuis l'apparition des premières feuilles sur son domaine. Pour cela, il peut procéder de deux façons: ou bien ne retenir qu'un jour dans la semaine ou bien diviser chaque fois l'indice par sept et effectuer ensuite la somme jour par jour. Pour des raisons techniques, on envoie le bulletin complet (toutes les stations considérées) à chaque abonné.
Mesure de l'humectation: transformation d'un thermohygrographe en thermohumectographe et application à une station automatique agroclimatique1
Authors: PINGUET A.
Published: April 2008

Le Service Technique d'Etudes des Facteurs Climatiques de l'Environnement (STEFCE) de l'Institut National de la Recherche Agronomique (INRA) de France a mis au point un « kit » de montage permettant de transformer un thermohygrographe en appareil enregistrant, outre la température et l'humidité, la durée d'humectation. L'enregistrement simultané de ces trois paramètres permet ainsi d'évaluer les risques de développement des parasites de certaines plantes. Ce principe a étéétendu à une station agroclimatique automatique qui numérise et enregistre les informations.