bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methods for Detection of Potato Cyst Nematodes1
Authors: Southey J.F. 
Published: April 2008

AbstractMethods are reviewed for inspection of growing potato crops and of soil sampling for detection and estimation of potato cyst nematodes (Heterodera rostochiensis Woll. and H. pallida Stone). Modifications of the Dutch soil‐sampling method are now widely used in Europe, including U.K. The statistical principles of soil sampling for Heterodera cysts are discussed. It is concluded that the efficiency of the method for detection is best improved by increasing both the quantity of soil examined and the number of sampling points per area sampled; the quantity is the most important factor which determines the level of infestation that can be detected. The area represented by a standard sample should be the same as that for which a separate decision will be made; variations in this area are unimportant because in effect one is sampling from an infinite population. It is concluded also that effective systems of control on potato‐growing land, and removal of soil from exported plants and potatoes, offer better prospects than soil sampling for preventing transport of cysts; a combination of these methods provides the best safeguard, e.g. for seed potatoes.
Reflections on Heterodera rostochiensis1
Authors: OOSTENBRINK M. 
Published: April 2008

AbstractIn 1955, the EPPO Heterodera rostochiensis Conference held in Wageningen (Anon., 1955) came to conclusions and recommendations which are analyzed together with other papers issued by EPPO between 1951–1959.In the course of the 18 years which elapsed since the Conference, major advances have been made in the following fields:– Origin, spread and distribution of the nematode, numerical dynamics and distribution of the nematode.– Numerical dynamics and genetic density and flexibility of nematode populations.– Breeding resistant potato varieties.– Development of new nematicides and integrated control.– Ecological limitations.Progress achieved along these lines is reviewed.
Host‐plants of Heterodera rostochiensis Woll. and the Breeding for Resistance1)
Authors: Huijsman C.A. 
Published: April 2008

AbstractThe two most important aspects of the host‐parasite relation of the potato and the tomato versus Heterodera rostochiensis Woll. are discussed. Many transitory forms between very poor and good hosts have been found in wild and primitive forms of these crops. The nature and the mode of inheritance of forms are described and their consequences for breeding work discussed. Several patho‐types are found and it is argued that many more exist.Much variation has also been found in the amount of damage in good hosts when heavily attacked. Some varieties, both in potato and in tomato, have been found with a high degree of tolerance to damage.
Chemical Control of Heterodera rostochiensis Woll.1)
Authors: Ouden H. den 
Published: April 2008

AbstractIn Dutch field experiments with Heterodera rostochiensis Woll. systemic nematicides at low and high nematode densities resulted in unfavourable cost/ benefit relations, as compared to other control procedures; on average, a 50 % reduction of the maximum multiplication of the nematode was observed. In England, better results were obtained at high nematode densities when higher dosages of nematicides were worked into the soil at a depth of 15 cm.In order to obtain a better effect of the mostly used contact nematicide DD‐mixture at a moderate dosage, a special treatment of the soil surface with the non‐fumigant dazomet was combined with the fumigation. On clay soil more than 99 % kill of stem nematodes was obtained with 30 g dazomet + 50 ml DD‐mixture per m When 10 g dazomet was added a 80% kill of Rolylenchus uniformis (Thorne) could be obtained on sandy soil; this was equivalent to 2 applications of the DD‐mixture alone. The combined treatment offers the great advantage of increasing the chances by 3 times to make the appropriate choice of the year for the treatment. Eggs of R. uniformis and H. rostochiensis are less susceptible to DD‐mixture than free living larvae and adults.
Thoughts on Quarantine Problems
Authors: Mathys G. 
Published: April 2008

AbstractPlant quarantine is a part of crop protection strategies and has generally not received the scientific support it deserves neither has the usefulness of quarantine actions which are a matter of public policy been verified. Experience shows that introduction of exotic pathogenic organisms often fails in establishment because the complicated sets of biological conditions needed are not met; however, with increased frequency of introductions, the probability of meeting the right combination of circumstances increases. This is of fundamental importance in quarantine.Protecting a bio‐geographical area rather than individual countries against emigrant pests and diseases is a prerequisite for a successful quarantine. It is explained how this approach is currently implemented within the EPPO area on the grounds of scientific data.A major breakthrough in evaluating the potential hazards inherent in emigrant pests has been made in the United States through mathematical modelling. Many gaps in the biological knowledge remain and there is a clear need for collaborative action on a global scale.
Health Aspects of Pesticides and their Residues1
Authors: Bressau G. 
Published: April 2008

AbstractVarious important factors in the evaluation of the acute and chronic toxicity of agricultural pesticides are discussed. Special attention is drawn to the residues in food and fodder of active ingredients, including their degradation and reaction products. A general evaluation of the effects of pesticides on roan, animals and the environment is only possible if their properties and behaviour in the different fields of application and under various conditions are known. This is illustrated by a few examples.Manufacturers (especially involved in residue analysis), chemists, toxicologists, biologists, advisors, farmers and operators dealing with pesticides are faced with many questions and problems which can only be solved through close cooperation. Public authorities and responsible organizations have to elaborate national and international guide‐lines, rules and regulations, which have to be constantly improved and adapted to the latest state of knowledge ‘for the sake of safety and efficacy.’The expression « health aspects » is often used as a synonym for « toxicological aspects ». In order to avoid misunderstandings, it is pointed out that toxicology is merely one important part of general health aspects; this is illustrated by some examples.
Taxonomy of Potato Cyst‐Nematodes1
Authors: Stone A.R. 
Published: April 2008

AbstractPotato cyst‐nematode pathotypes fall into 2 groups distinguished by morphological and biological differences, corresponding to the species Heterodera rostochiensis Wollenweber, 1923 (the golden nematode) and H. pallida Stone, 1973. The species may most readily be distinguished by differences in length and knob shape of second stage juveniles' stylets, by differences in the cuticular pattern of the female or cyst perineum (the region between vulva and anus) and by the colour of the maturing female. Both species occur in the United Kingdom, continental Europe, South America and elsewhere, and include pathotypes able to develop on potato cultivars bearing genes for resistance.
Désherbage et environnement1
Authors: Mathys G. 
Published: April 2008

SommaireL'étude des répercussions des herbicides sur la biosphère a suscité un vif intérêt depuis que la sauvegarde de l'environnement est devenue une préoccupation prioritaire. La documentation qui s'y réfère est encore fragmentaire; elle concerne l'impact de ces produits sur la faune sauvage, les poissons et les abeilles, ainsi que sur le sol et l'eau en général. Il est fait état des recherches dans ces domaines et des conclusions que l'on peut en tirer. L'eau demeure un point vulnérable dans le cadre des applications de certains herbicides en raison des dangers de contamination par la dérive et des possibilités d'infiltration dans les zones de captage d'eau potable.
Recent Developments in Deciduous Orchard Pest Management in the United States1
Authors: Glass E.H. 
Published: April 2008

AbstractA realistic appraisal of insect and mite control on apple suggests that the existing status of almost total reliance on chemicals is very precarious. During the past 10 to 15 years integrated systems of biological control of mites and chemical control of insects have been developed. The most common integrated system makes use of predacious phytoseiid mites resistant to insecticides used for the control of major pests.In the United States, there are currently 4 federally funded apple pest management projects (Washington, Pennsylvania, Michigan and New York). While there are differences among these in their scope and structure, they all aim at implementing new pest management systems on a commercial level and to train fruit pest managers.SummaryThe pest problems on apples in North America, which include insects, mites, fungal, virus and bacterial disease organisms, weeds and mammals, are very complex and difficult to solve. Chemical control of insects has been practised on this fruit since before 1900 with considerable success but there have been problems of acquired resistance and destruction of parasites and predators by certain insecticides and fungicides. As a result mites and a few insects have become greater problems than formerly. Currently organophosphates are being used as the basic control agents for most insects. Phytophagous and some predacious mite species are now resistant to these materials. Chemical control is needed in all commercial apple planting to prevent severe fruit damage.During the past 10 to 15 years successful integrated systems of biological control of mites and chemical control of insects have been developed in several widely scattered apple‐growing areas. Fruit growers are using these more or less depending upon the severity of mite problems and the availability of effective acaricides. The most common integrated system makes use of predacious phytoseiid mites which have developed resistance to insecticides essential to controlling major insect pests of apple. All pesticides known to be harmful to these mites are avoided during critical periods. In Pennsylvania an integrated system employing the chrysomelid beetle, Stethorus punctum, is used. In this case, the predator is preserved by using reduced dosages and limited spray coverage.Considerable progress has been made in recent years in reducing the quantity of insecticide used on apple. The basis for the reduction has been the use of very effective insecticides which essentially eliminate major pests from orchards. This level can be maintained by reduced schedules, i.e., applying treatments only when pests are present as indicated by monitoring and inspections. The development of sex pheromone traps has enabled excellent progress in this direction.Currently there are 4 federally funded pest management projects in important apple‐producing regions. The objectives are to implement new pest management systems on a commercial level and to train fruit pest managers.
The Feasibility of Environmental Control for the Protection of Stored Grain
Authors: Calderon M. 
Published: April 2008

AbstractRelevant data on the possibilities of changing the stored grain environment, for the sake of better preservation of grain in storage, are reviewed. The grain bulk is regarded as an ecosystem, in which the impact of damaging organisms can be controlled by ambient conditions. The influence of humidity, temperature, composition of atmospheric gases, atmospheric pressure and light is discussed. Lowering humidity and grain temperatures are well known effective and practical ways for the prevention of storage damage. The modification of atmospheric gas compositions has been subjected to very extensive research, on which new methods for insect control could be based. Lowering the absolute pressure in storage containers has detrimental effects on storage insects; the practical implementation of this technique is discussed. Research on the effects of changing light conditions on stored grain insects is in its earliest stage, but shows promise. Studies on an integrated approach using several environmental elements for the containment of grain insects and microflora are proposed.
Quelques problèmes de pathologie dans les rotations céréalières1
Authors: Cassini R. 
Published: April 2008

SommaireEn France, le maïs est souvent produit en monoculture ou placé en tête d'un assolement réduit à la rotation maïs‐blé, avec quelques variantes. D'autre part, cette culture s'étend vers des zones climatiques plus marginales à la faveur des nouveaux hybrides. Ces conditions, auxquelles s'ajoute l'uniformité des variétés, sont favorables au développement des maladies.Deux types de problèmes sont examinés dans le cadre de cette évolution; ils se rattachent aux affections suivantes: 1) les maladies communes au maïs et aux céréales à paille, comprenant notamment Fusarium roseum (Link) Sn. et H., et 2) les maladies spécifiques du maïs; elles se réfèrent àHelminthosporium turcicum Pass., H. maydis Nisikado et Miyake, race T et Kabatiella zeae Narita et Hiratsuka.Les possibilités de lutte contre ces différentes maladies sont examinées ainsi que les mécanismes qui peuvent être rendus responsables de leur virulence et de leur extension.
Crop Rotation, Monoculture and Soil Ecology1
Authors: Hoestra H. 
Published: April 2008

AbstractCrop rotation and monocultural systems are discussed in relation to disease management and control. The ecological basis of both systems is examined. In crop rotation the leading principle is that in the absence of host‐plants parasite populations invariably decline below threshold levels, mostly within a few years.Knowledge of the behaviour of parasite populations in the soil is becoming vast, especially in the case of plant parasitic nematodes. Analysis of soil samples for nematodes and fungi often helps the farmer to plan rotation schemes. From the ecological point of view, crop rotation is interpreted as a system of interrupted monocultures.Monocultural practices cannot be applied so universally as crop rotation, but in a number of cases monoculture is feasible, e.g. with cereals. In the equilibrium situation between host‐plant (e.g. cereals), parasite (Gaeumannomyces graminis [Sacc.] v. Arx & Olivier) and the antagonists of the parasite, growth of the crop is satisfactory. These cases illustrate the role of antagonists, and it is proposed to investigate more systematically monocultures in relation to antagonisms. This may lead to more opportunities for biological control of soil‐borne diseases.
Present Status of Research on Insect Growth Regulators for the Protection of Stored Grain1
Authors: Hoppe T. , Suchy M. 
Published: April 2008

AbstractTwo insect growth regulators of the juvenile hormone type, namely 6,7‐epoxy‐3‐ethyl‐(p‐ethylphenoxy)‐7‐methylnonane, cis/trans mixture (compound A) and 6,7‐epoxy‐3,7‐dimethyl‐1‐[3,4‐(methylendioxy)‐phenoxy]‐2‐nonene (compound B) have been tested for their persistence when treated on stored grain. The interim results of this trial showed inhibition of adult emergence of Ephestia kühniella Zell., Plodia interpunctella Hübn., Tribolium castaneum Herbst and Rhyzopertha dominica F. even 8 months after treatment. The gas‐chromatography residue determination of compound A showed a reduction of 27 % of the original concentration within 8 months. No effect of compound A on the endosperm of the grain or taste of flour and bread could be found in the Bakery School in Lucerne.
Diseases in Reduced Cultivation and Direct Drilling Systems1
Authors: Yarham D.J. , Hirst J.M. 
Published: April 2008

AbstractMould board ploughing, long the foundation of arable agriculture, has been replaced on many British farms by reduced cultivation systems not involving the inversion of the soil. There is also an increasing interest in direct drilling into untilled soil. The change to such techniques may be expected to influence the incidence of certain cereal diseases. Increases in Rhynchosporium secalis (Oud.) Davis and Septoria spp. have been noted in non‐plough situations where infected debris is left on the soil surface. Effects on other diseases are more complex and may be mediated through the effects of cultivation technique on time of sowing, crop establishment, weed control, pest incidence and other factors including the physical nutritional and microbiological characteristics of the soil.
Some Consequences of Cereal Monoculture on Gaeumannomyces graminis (Sacc.) Arx & Olivier and the Take‐all Disease1
Authors: Cunningham P. C. 
Published: April 2008

AbstractStudies were made of isolates of Gaeumannomyces graminis (Sacc.) Arx & Olivier var. tritici J. Walker from different length crop sequences of wheat and barley following permanent grassland. Studies were done on the influence of cropping intensity of soils, natural and steam disinfested, on disease expression from added inoculum. Efforts were also made to detect interactions between isolates and soils from the same and different cropping sequences. Investigation of variability in the pathogen related to virulence and specificity as well as to saprophytic traits.In general, mean virulence of isolates increased up to the point where approximately peak disease levels occurred in the field, and diminished subsequently. Host specificity of isolates from a monospecies system was also pronounced at this point whereas it was not evident in the first 2 crops; it did not increase further after the 5th or 6th cereal of a single species. There was evidence of loss of competitive saprophytic ability in isolates from long sequences as against those from 1st, 2nd and 3rd crops after permanent pasture. A differential sensitivity response from Gliomastix murorum (Cda.) Hughes var. felina (Marsh) Hughes was observed with isolates from 1 to a 3 year sequence compared with isolates from sequences of 4 to 8 years. Isolates from a 1st to a 3rd crop restricted colony growth of G. murorum in culture whereas those from 4th to the 8th cereal were overgrown by this fungus. Isolates from the 1st cereal after grass darkened considerably with age, those from a 2nd less so and those from a 3rd successive crop remained almost totally hyaline; those from longer sequences darkened considerably but were very variable for this trait. The influence of soil from more intensively cropped cereal sequences, which was destroyed by steam disinfestation, was to depress disease levels from applied inoculum. This soil inhibitory effect set in between the first and 3rd cereal.
Anatomie fine de Cercosporella herpotrichoides Fron dans les gaines foliaires de froment. Observations sur la percée des parois des cellules‐hôtes 1)
Authors: Rassel A. 
Published: April 2008

SommaireD'une étude en microscopic électronique de Cercosporella herpotrichoides Fron parasitant des gaines foliaires de froment, il résulte que le métabolisme du champignon est particulièrement actif. L'attention est attirée sur les phénomènes d'autophagie, de turn over de substances de réserve et sur la percée des parois pectocellulosiques des cellules‐hôtes.RésuméDes cellules mycéliennes de C. herpotrichoides ont été observées à l'intérieur de cellules de gaines foliaires de froment et classées en 5 catégories d'âge. Les observations ont porté plus particulièrement sur les cellules jeunes et adultes.La paroi émet un exsudat. Les parois transversales sont munies de pores septaux ouverts ou bouchés entourés de corps de Woronin. La membrane plasmique donne lieu à la formation de lomasomes et d'invaginations isolant des portions cytoplasmiques appauvries. Le cytoplasme contient des particules α et β de glycogène, des mitochondries, un réticulum endoplasmique peu développé, des inclusions claires dépourvues de membranes et vraisemblablement des peroxysomes. Les vacuoles contiennent généralement un gros globule et de petites vésicules issues de bourgeonnements du tonoplaste. Des phénomènes d'autophagie par séquestration de matériel cytoplasmique dans des doubles membranes et des vacuoles ont été repérés.La percée des parois cellulaires de l'hôte s'accompagne toujours d'une réduction du diamètre du filament mycélien à l'endroit de passage. Dans les vaisseaux, elle a lieu au niveau des ponctuations. Après un choix thigmotropique du site de pénétration et adhérence du parasite à la paroi grâce à l'exsudat émis, la percée se fait par voie enzymatique. Des phénomènes de pression sont suggérés.On peut conclure de ces observations que, dans les conditions de l'essai, le métabolisme du parasite est particulièrement actif.
Fungi and the Decrease of Cereal Cyst‐nematode Populations in Cereal Monoculture1
Authors: Kerry B.R. 
Published: April 2008

AbstractPopulations of the cereal cyst‐nematode decrease when cereals are grown frequently or continuously because the females that develop on the roots between May and July fail to produce eggs, or produce a smaller number than expected. Consequently, cysts in the soil after harvest are fewer and contain fewer eggs. The role of fungal parasites and competitors in limiting populations of cyst‐nematodes is reviewed. Parasites of eggs and females of Heterodera avenae Woll. were widespread in British cereal fields, an Entomophthora‐like fungus and Verticillium chlamydosporium Barron & Onions being the most common species found. Although fungal parasites may be the cause of the failure of the nematode to increase, it has not yet been established unequivocally.