Wie repräsentativ sind die Stichprobenverfahren von landwirtschaftlichen Expertensystemen?     

Dipl.-Geogr. Gregor Spickermann  Prof. Dr. Lutz Plümer 《Gesunde Pflanzen》2003,55(8):222-227

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A case history of psittacosis in the dog   总被引：2，自引：0，他引：2  

G Fraser  J Norval  A R Withers  W W Gregor 《The Veterinary record》1969,85(3):54-58

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EU regulatory aspects of resistance risk assessment     

Heimbach U  Kral G  Niemann P 《Pest management science》2002,58(9):935-938

The EPPO Standard PP 1/213(1) on resistance risk analysis is the basis for risk assessment within the authorisation process in Germany. Data for resistance risk analysis have to be provided by the applicant and risk-mitigation strategies prepared if necessary. The extent of data requirements and the intensity of the evaluation process depend mainly on the type of target organism, crop, mode of action of the active substance and the resistance history of the organism in combination with products of similar mode of action as the one being applied for. Because resistance risk is a very complicated issue during the authorisation of plant-protection products, intensive co-operation between applicants and regulators is essential prior to submission of the dossier, with due consideration of the amount of data necessary and, where required, the proposed resistance-management strategy.  相似文献   

New developments in insecticide resistance in the glasshouse whitefly (Trialeurodes vaporariorum) and the two-spotted spider mite (Tetranychus urticae) in the UK     

Gorman K  Hewitt F  Denholm I  Devine GJ 《Pest management science》2002,58(2):123-130

A recent survey of insecticide resistance in two of the most problematic pests in UK glasshouses revealed some new developments. At least some individuals in all UK samples of Trialeurodes vaporariorum that were tested resisted the insect growth regulator (IGR) buprofezin. The most strongly resistant strains were unaffected by the field application rate of this compound, and even samples from populations that had never been exposed to buprofezin contained individuals that survived the highest concentration applied (10,000 mg litre-1). The field rate of buprofezin was shown to select for resistance through vapour action alone. The benzophenylurea teflubenzuron, an unrelated IGR, was cross-resisted by buprofezin-resistant individuals. There was no evidence of resistance to imidacloprid, but all T vaporariorum strains tested, regardless of origin, exhibited a high innate tolerance to nicotine, when compared with another whitefly species, Bemisia tabaci. Marked resistance to fenbutatin oxide and tebufenpyrad was found in single glasshouse populations of Tetranychus urticae, but these compounds and abamectin appeared to remain highly effective against all other strains collected.  相似文献   

Infection of Norway spruce (Picea abies (L.) Karst.) seedlings with Pythium irregulare Buism. and Pythium ultimum Trow.: histological and biochemical responses     

Gregor Kozlowski  Jean-Pierre Métraux 《European journal of plant pathology / European Foundation for Plant Pathology》1998,104(3):225-234

We have studied the reaction of Picea abies seedlings to infection with Pythium. The highly virulent species Pythium ultimum and the less virulent species Pythium irregulare germinated on the root and hypocotyl surface, formed appressoria and penetrated through the stomata as well as through the epidermis. No major differences in the growth of both fungal species were observed during the early events of colonization. The less virulent species formed about 25% more appressoria suggesting that the fungus experienced difficulties with penetration. Differences were observed in the response of the host plant to infection. Autofluorescence, possibly related to deposition of lignin or lignin-like materials increased more in cortical and endodermal tissue colonized with the highly virulent P. ultimum than with the less virulent P. irregulare. Chitinase activity was highest in the tissues most extensively colonized by the fungus. In addition, a systemic increase of chitinase activity was also detected. Interestingly, chitinase activity increased systemically in cotyledons which were never in contact with the pathogen, indicating the translocation of a systemic signal. Salicylic acid was also detected in spruce seedlings; its level increased in roots during infection with the less virulent P. irregulare.  相似文献   

Synanthropy of Anthomyiidae, Muscidae and Calliphoridae (Diptera) in Cuba.     

F Gregor 《Folia parasitologica》1975,22(1):57-71

The material of 22302 flies of Anthomyiidae, Muscidae and Calliphoridae collected by trap-method in Cuba 1966 was qualitatively and quantitatively analysed. Relative density, seasonal incidence and food preference were ascertained in 20 species. In potential vectors of human diseases the ecological characters and classification of synanthropy are given.  相似文献   

Report of resistance to the neonicotinoid insecticide imidacloprid in Trialeurodes vaporariorum (Hemiptera: Aleyrodidae)   总被引：1，自引：0，他引：1  

Gorman K  Devine G  Bennison J  Coussons P  Punchard N  Denholm I 《Pest management science》2007,63(6):555-558

Susceptibilities of UK and mainland European samples of Trialeurodes vaporariorum (Westwood) to the neonicotinoid insecticide imidacloprid were investigated over a 7 year period. All 24 strains collected between 1997 and 2003 showed similar baseline levels of susceptibility to that of a known susceptible laboratory strain when exposed to a diagnostic concentration (128 mg L(-1)) of formulated imidacloprid. Two samples collected during 2004, one from the UK and one from The Netherlands, demonstrated reduced susceptibility at this concentration. Using dose-response assays, the presence of resistant individuals was disclosed in both these strains; some individuals were unaffected at doses high enough to induce phytotoxic effects. This report represents the first confirmed cases of neonicotinoid resistance inducing control failures in T. vaporariorum, and highlights a need for careful vigilance to sustain the effectiveness of imidacloprid and related neonicotinoid insecticides.  相似文献   

Large-scale historical afforestation failure with Pinus cembra in the Swiss Prealps     

Fragnière  Yann  Sonnenwyl  Vincent  Clément  Benoît  Kozlowski  Gregor 《New Forests》2022,53(3):533-553

New Forests - Between the nineteenth and early twentieth centuries, large-scale afforestation projects were undertaken in the Swiss Prealps. The Swiss stone pine (Pinus cembra L.), an emblematic...  相似文献   

Diel fluctuation of soluble phosphorus in the tank water of rainbow trout, Oncorhynchus mykiss (Walbaum), and relationships with feed inputs and dissolved oxygen     

Gregor K Reid  & Richard D Moccia 《Aquaculture Research》2006,37(15):1606-1610

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Silicon nutrition of tomato and bitter gourd with special emphasis on silicon distribution in root fractions     

Gregor Heine  George Tikum  Walter J. Horst 《植物养料与土壤学杂志》2005,168(4):600-606

Two plant species, tomato (Lycopersicon esculentum Mill.) and bitter gourd (Momordica charantia), were used for in‐depth studies on the dynamics of silicon (Si) uptake and translocation to the shoots and compartmentation of Si in the roots. The experiments were conducted under controlled environmental conditions in nutrient solutions, which were partly amended with 1 mM Si in the form of silicic acid. At harvest, xylem exudates were collected, and Si concentrations and biomass of roots and shoots were determined. Mass flow of Si was calculated based on the Si concentration of the nutrient solution and transpiration determined in a parallel experiment. Plant roots were subjected to a fractionated Si analysis, allowing attributing Si to different root compartments. Silicon concentrations in the roots compared to the shoots were higher in tomato but lower in bitter gourd. A more ready translocation from the roots to the shoots in bitter gourd was in agreement with Si concentrations in the xylem exudates which were higher than in the external solution. In tomato, the xylem‐sap Si concentration was lower than in the nutrient solution. Calculated Si mass flow to the root exceeded Si uptake in tomato, which was consistent with the measured accumulation of Si in the root water‐free space (WFS). In contrast, Si concentration in the root WFS was lower than in the nutrient solution in bitter gourd, reflecting the calculated Si depletion at the root surface based on the comparison of Si mass flow and Si uptake. Within the roots, more than 80% of the total Si was located in the cell wall and less than 10% in the cytoplasmic fractions in tomato. In bitter gourd, between 60% and 70% of the total root Si was attributed to the cell‐wall fraction whereas the proportion of the cytoplasmic fraction reached more than 30%. Our results clearly confirm that tomato belongs to the Si excluders and bitter gourd to the Si‐accumulator plant species for which high Si concentrations in the cytoplasmic root fraction appear to be characteristic.  相似文献