Heat resistance,biology and prevention of Diehliomyces microsporus in crops of Agaricus species     

Annemarie Van Zaayen  Bernarda Van Der Pol-Luiten 《European journal of plant pathology / European Foundation for Plant Pathology》1977,83(6):221-240

Soon after its introduction the mushroom speciesAgaricus bitorquis, which is immune to virus disease and prefers a warm climate, was threatened by the competitorDiehliomyces microsporus, false truffle. This fungus also likes warmth, and used to occur in crops ofA. bisporus.Mycelium and ascocarps were grown on several nutrient media. Optimum temperatures for mycelial growth were 26°C and 32°C, with a slight depression at 30°C. In trials in isolated growingrooms strain Somycel 2.017 ofA. bitorquis was generally used since it appeared to be highly sensitive to the competition of false truffle. Inoculation with mycelium, ascocarps or ascospores ofD. microsporus nearly always resulted in the presence of the competitor and in decreased mushroom yields. Even ten spores per m² causedD. microsporus. The time of inoculation was most important: irrespective of the kind of inoculum, inoculation only resulted in both false truffle and yeild loss, if applied from spawning until a few days after casing. Inoculation at a later date could result in false truffle, but yield was not decreased.As germination in vitro of ascospores failed, even after addition of various triggers, ascospore suspensions were treated at various temperatures for several periods. Then mushroom growing trays spawned with Somycel 2.017 were inoculated with the treated suspensions giving 7–11×10⁷ spores/m². The ascospores could not withstand 85°C for 0.5 h, 80°C for 1 h and 70°C for 3 h. Spontaneous incidence of false truffle, however, could not always be prevented and interfered with the results of these trials. It is possible that the thermal death-point of the ascospores is below 85°C. Fruiting bodies and ascospores did not survive peak-heating at the beginning and cooking out (compost temperature 12 h at 70°C) at the end of a crop. After cooking out, however,D. microsporus could still be present in the wood of trays and contaminate a following crop if no wood preservative was applied.Yield of Somycel 2.017 was reduced by the competition ofD. microsporus much more than yeilds of other strains ofA. bitorquis. The least sensitive were the highly productive strains Horst K26 and Horst K32.The effects of fungicides onD. microsporus in vitro and in growing trials did not correspond. The fungicides tested so far could not prevent or controlD. microsporus. Growing of less sensitive strains ofA. bitorquis together with sanitary measures early in the crop and at the end of the crop, however, can prevent the competitor. failure to turn up of false truffle. To understand the discrepancy between the in vitro effects of several fungicides and their effect in inoculated mushroom trays, the rate of adsorption of benomyl in the substrate and probably the interrelationships between antagonists andD. microsporus require further research. Other strains ofA. bitorquis than Somycel 2.017 appeared to be less sensitive to the competition. Among these, highly productive strains Horst K26 and Horst K32 will not be hindered byD. microsporus if the following precautions are exercised: cooking out at the end of a crop (compost temperature 70°C for 12 hours), followed by treatment of the wood with SPCP; protection by hygiene early in the crop, i.e. covering of the compost by a thin plastic sheet during mycelial growth followed by a quick execution of casing.Samenvatting De teelt van de warmteminnende champignonsoortAgaricus bitorquis, die immuun is voor virusziekte, werd al spoedig na introductie bedreigd door de eveneens warmteminnende concurrentDiehliomyces microsporus, valse truffel. Deze schimmel kwam vroeger voor in teelten vanA. bisporus; de sporen zouden een temperatuur van 82°C gedurende 5 uur kunnen overleven (Lambert, 1932). Tabel 1 geeft de myceliumgroei op verschillende voedingsbodems en de vorming van vruchtlichamen (Fig. 1A, B) weer. De optimale temperaturen voor myceliumgroei waren 26°C en 32°C, met een licht depressie bij 30°C (Fig. 2). Proeven in geïsoleerde teeltruimten werden voornamelijk uitgevoerd met Somycel 2.017, een ras vanA. bitorquis. Inoculatie met mycelium, vruchtlichamen en/of ascosporen vanD. microsporus, al of niet in reincultuur gekweekt, leidde vrijwel steeds tot de aanwezigheid van de concurrent in de geïnoculeerde teeltkisten (Fig. 1C, D), waarbij vruchtlichamen met ascosporen (Fig. 1E) gevormd werden en tot een reductie van het aantal champignons. Tien sporen per m² waren al voldoende omD. microsporus te doen aanslaan (Fig. 3). Het tijdstip van inoculatie bleek van groot belang te zijn: onafhankelijk van de aard van het inoculum leverde dit slechts zowel valse truffel als oogstreductie op, indien het werd aangebracht in de periode vanaf enten tot enkele dagen na het afdekken (Tabel 2 en Fig. 4). Inoculatie op latere tijdstippen kon wel tot valse truffel leiden, maar niet tot oogstreductie.Aangezien de kieming van ascosporen in vitro slechte resultaten opleverede, ook na toevoeging van diverse stimulantia, werden ascosporensuspensies in vitro gedurende verschillende tijden bij verschillende temperaturen behandeld; vervolgens werden teeltkisten met de behandelde suspensies geïnoculeerd (7 tot 11×10⁷ sporen/m²). De kisten waren tevoren geënt met Somycel 2.017. Een aantal proeven wees uit, dat de ascosporen 1/2 uur 85°C, 1 uur 80°C en 3 uur 70°C, niet overleefden (Tabel 3). Het spontaan optreden van valse truffel kon echter niet altijd worden voorkomen en beïnvloedde de uitkomsten van deze proeven. Daarom is het mogelijk, dat de sporen al bij een lagere temperatuur worden gedood Vruchtlichamen en ascosporen werden gedood door het uitzweten aan het begin van een teelt en door het doodstomen aan het einde van een teelt (composttemperatuur 12 uur 70°C) maar de schimmel bleek in het laatste geval wel over te kunnen blijven in het hout van teeltkisten als er vervolgens geen houtontsmettingsmiddel werd toegepast.Somycel 2.017 leed verhoudingsgewijs meer schade door concurrentie vanD. microsporus dan enkele andere rassen (Tabel 4 en. 5). Inoculatie met ascosporen bleek bij de minst gevoelige en meest produktieve rassen Horst K26 en Horst K32 slechts te gelukken in extreem droge compost; bij Somycel 2.017 daarentegen zowel in compost met een laag als met een hoog vochtgehalte. Inoculatie met mycelium veroorzaakte meer valse truffel en meer schade naarmate de compost natter was (Tabel 5).De werking van een aantal fungiciden in vitro (Tabel 6) en in teeltkisten (Tabel 7) stemde niet overeen. Aangezien de tot nu toe getoetste fungicidenD. microsporus niet kunnen voorkomen of bestrijden, moet preventie van deze concurrent worden gezocht in het telen van weinig gevoelige rassen vanA. bitorquis in combinatie met hygiënische maatregelen vroeg in en aan het eind van de teelt.  相似文献   

Development of comparable agro‐climatic zones for the international exchange of data on the efficacy and crop safety of plant protection products1     

E. Bouma 《EPPO Bulletin》2005,35(2):233-238

Data on the efficacy and crop safety of plant protection products can be used for registration purposes in other countries, provided crop growth conditions are comparable. This article identifies the main conditions which are relevant in this respect, with particular emphasis on climatic conditions. Comparison of several systems of agro‐climatic classification developed for the EPPO region, particularly the climate diagrams of Walter & Lieth, the climate classification system of Köppen & Geiger, the agro‐climatic areas of Thran & Broekhuizen and natural vegetation maps, has led to a division of the EPPO region (Europe, Mediterranean area, Middle East) into four agro‐climatic zones (Mediterranean, Maritime, North‐east, Central) within which conditions can be considered comparable.  相似文献   

Decision support systems used in the Netherlands for reduction in the input of active substances in agriculture     

E. Bouma 《EPPO Bulletin》2003,33(3):461-466

Since the middle of the 1980s, Dutch farmers have been using decision support systems (DSS) as an aid in the control of pests. This started with EPIPRE, then weather-related potato blight warning systems were developed (Prophy and Plant-Plus). In the 1990s, many weather-based DSS were developed against pests of orchards, flower bulbs, arable crops and field-produced vegetables. Also, a DSS was developed to predict and check the effect of meteorological conditions on the effectiveness of application timing of plant protection products (GEWIS). The use of these systems resulted in more sustainable crop protection: sustainable because the use of DSS led to a lower risk of crop damage and, in many cases, to a lower input of active substances, by optimization of the product and dose to actual phytosanitary and meteorological conditions. The use of GEWIS to ensure application at the right time of day further reduced the input of active substances and increased efficacy.  相似文献   

Analytical validation of platelet microparticle quantification in cats          下载免费PDF全文

Signe E. Cremer  Jørgen Koch  Nanna Graversen  Anne S. Gravgaard  Rebecca Langhorn  Annemarie T. Kristensen  Jakob L. Willesen  Lise N. Nielsen 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2018,47(3):386-395

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How to characterize ‘good’ and ‘greening’ in the EU Common Agricultural Policy (CAP): the case of clay soils in the Netherlands          下载免费PDF全文

J. Bouma  J. H. M. Wösten 《Soil Use and Management》2016,32(4):546-552

The change in the Common Agricultural Policy (CAP) of the European Union from product to producer support, including requirements for ‘good agricultural and environmental conditions’ and ‘greening’, is excellent. However, these requirements are now defined in rather general terms. Questions can be raised about suitable indicators, and there is a recognized need for effective management recommendations to support farmers in achieving the required ‘good’ conditions. These recommendations are bound to be quite different for different soils in different countries. A study of Dutch clay soils was based on a storyline describing current problems and management options for improvement, which were quantified using a soil–water–crop simulation model. Indicators were defined for agricultural conditions and suggestions made for the use of the model in a predictive mode to help farmers improve their soil management. Environmental conditions were judged by current environmental guidelines for water and air. When modelling, implicit assumptions that soils are homogeneous were shown to be unrealistic for these clay soils, requiring development of innovative methods and procedures, presenting a challenge for soil research.  相似文献   

Drainage and vertical hydraulic conductivity of some Dutch “knik” clay soils     

J. Bouma  L. W. Dekker  H. L. Verlinden 《Agricultural Water Management》1976,1(1):67-78

The vertical K-sat of a clay layer, occurring between 30 and 60 cm below the soil surface, was measured in situ in early spring at thirteen sites, using large soil columns. Gypsum was used to form a barrier around the column and K-sat values were measured with an infiltrometer in columns that were first attached and then detached from the subsoil. This procedure allows an estimate of the occurrence of large continuous pores, such as vertical worm channels. Highest values were found in tile-drained grassland, followed by grassland with surface drainage only, and by tile-drained arable land. Relatively low K-sat for the silty subsoil, rather than the (high) vertical K-sat for the clay layer, is considered to be responsible for high groundwater tables in the wet season.Undisturbed, large columns were taken to the laboratory and saturated for a period of three months to simulate prolonged swelling after a very wet season, and to measure chloride-breakthrough curves, for characterizing soil-pore continuity. The clay layer, sampled in the surface-drained grassland, showed no significant reduction of K-sat after prolonged swelling, but the one for arable land was reduced. Moreover, flow in the latter occurred through only a few relatively large, continuous pores, whereas a more heterogeneous pore system was found for the column from grassland. The already high K-sat of the clay layer in surface-drained grassland increased as a result of tile drainage. Compaction of the clay layer in tile-drained arable land reduced K-sat well below the level found in surface-drained grassland.  相似文献   

Comparison of performance of dairy herds that were or were not vaccinated with a bovine herpes virus 1 marker vaccine in 1998     

Bartels CJ  Barkema HW  Beiboer ML  Bouma A  Stegeman JA 《Tijdschrift voor diergeneeskunde》2001,126(6):191-197

This study analysed the effects of the use of bovine herpesvirus 1 (BHV1) marker vaccine on the performance of dairy cattle. In Spring of 1999, vaccination of 12 herds with the BHV1 marker vaccine resulted in severe animal health problems and mortality. The vaccines used on these farms were all from a batch that appeared to be contaminated with bovine virus diarrhoea virus type 2. This led to a general call to farmers and veterinary practitioners to report side-effects of this vaccine. As a result, more than 7000 farmers reported symptoms. The information was obtained by means of a questionnaire; there was no control group. To determine the effects of the use of the marker vaccine, it was necessary to perform a study based on objectively acquired information. The information collected by the Royal Dutch Cattle Syndicate and the office of Identification and Registration was complied into herd indices on production, udder health, reproduction, and culling. Two groups of dairy farms that had used the BHV1 marker vaccine (attenuated and inactivated vaccine) were compared with farms that were certified BHV1-free. The analyses were performed based on intra-herd comparisons, meaning that per herd each index calculated over a certain period of time after the use of the marker vaccine was compared to a similar period of time prior to the use of the marker vaccine. A total of 144 comparisons were made. Seven comparisons were statistically significant. In two comparisons, the results were in favour of the BHV1-free farms and in five comparisons, the result were in favour of the vaccinated farms. Thus use of the BHV1 marker vaccine could not be proven to affect herd performance. The sensitivity of the tests was very high, so with a high level of probability even very small differences in indices between groups would have been detected.  相似文献   

CONTRAST-ENHANCED ULTRASONOGRAPHY IN NORMAL CANINE LIVER. EVALUATION OF IMAGING AND SAFETY PARAMETERS     

Helena T. Nyman  Annemarie T. Kristensen  Mads Kjelgaard-Hansen  Fintan J. McEvoy 《Veterinary radiology & ultrasound》2005,46(3):243-250

Contrast-enhanced ultrasonography, a new imaging modality in veterinary medicine, can provide data on tissue perfusion. The objective of this study was to use the ultrasonographic contrast agent SonoVue to evaluate various transit time indices in the normal canine liver, to examine the effect of anesthesia on these parameters, and to evaluate the safety of this agent in dogs. The liver of 11 healthy dogs was studied by ultrasound during an intravenous bolus injection of SonoVue. Each dog underwent the examination twice, first with and later without the use of anesthesia. A time-intensity curve was generated from a selected region of interest within the liver from each scanning session. Ratios derived from peak enhancement, time to peak enhancement, up-slope and full-width half-maximum (FWHM) of the curve were calculated from the time-intensity curves, and are reported. There were no statistically significant differences (P > 0.05) in peak enhancement, up-slope and FWHM between dogs that were anesthetized and dogs that were not. Time to peak enhancement, however, was significantly shorter when the dogs were anesthetized than when they were nonanesthetized (P < 0.05). There were no biologically significant changes in clinical laboratory findings. This study indicates that contrast-enhanced ultrasound using SonoVue gives reproducible liver perfusion data, and appears to be a safe and well-tolerated agent for use in dogs. When considering normal values, the use of anesthetic drugs has to be considered.  相似文献   

Transmission of classical swine fever virus within herds during the 1997-1998 epidemic in The Netherlands     

Stegeman A  Elbers AR  Bouma A  de Smit H  de Jong MC 《Preventive veterinary medicine》1999,42(3-4):201-218

In this paper, we describe the transmission of Classical Swine Fever virus (CSF virus) within herds during the 1997–1998 epidemic in the Netherlands. In seven herds where the infection started among individually housed breeding stock, all breeding pigs had been tested for antibodies to CSF virus shortly before depopulation. Based upon these data, the transmission of CSF virus between pigs was described as exponential growth in time with a parameter r, that was estimated at 0.108 (95% confidence interval (95% CI) 0.060–0.156). The accompanying per-generation transmission (expressed as the basic reproduction ratio, R₀) was estimated at 2.9. Based upon this characterisation, a calculation method was derived with which serological findings at depopulation can be used to calculate the period in which the virus was with a certain probability introduced into that breeding stock. This model was used to estimate the period when the virus had been introduced into 34 herds where the infection started in the breeding section. Of these herds, only a single contact with a herd previously infected had been traced. However, in contrast with the seven previously mentioned herds, only a sample of the breeding pigs had been tested before depopulation (as was the common procedure during the epidemic). The observed number of days between the single contact with an infected herd and the day of sampling of these 34 herds fitted well in the model. Thus, we concluded that the model and transmission parameter was in agreement with the transmission between breeding pigs in these herds.

Because of the limited sample size and because it was usually unknown in which specific pen the infection started, we were unable to estimate transmission parameters for weaned piglets and finishing pigs from the data collected during the epidemic. However, from the results of controlled experiments in which R₀ was estimated as 81 between weaned piglets and 14 between heavy finishing pigs (Laevens et al., 1998a. Vet. Quart. 20, 41–45; Laevens et al., 1999. Ph.D. Thesis), we constructed a simple model to describe the transmission of CSF virus in compartments (rooms) housing finishing pigs and weaned piglets. From the number of pens per compartment, the number of pigs per pen, the numbers of pigs tested for antibodies to CSF virus and the distribution of the seropositive pigs in the compartment, this model gives again a period in which the virus most probably entered the herd. Using the findings in 41 herds where the infection started in the section of the finishers or weaned piglets of the age of 8 weeks or older, and of which only a single contact with a herd previously infected was known, there was no reason to reject the model. Thus, we concluded that the transmission between weaned piglets and finishing pigs during the epidemic was not significantly different from the transmission observed in the experiments.  相似文献   

Decreased platelet function in Cavalier King Charles Spaniels with mitral valve regurgitation     

Tarnow I  Kristensen AT  Texel H  Olsen LH  Pedersen HD 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2003,17(5):680-686

With aggregometry, increased platelet activity has been reported in Cavalier King Charles Spaniels (CKCS) without mitral regurgitation (MR). In contrast, dogs with MR have been found to have decreased platelet activity. The purpose of this study was to test an easy bedside test of platelet function (the Platelet Function Analyzer [PFA-100]) to see if it could detect an increase in platelet activity in CKCS without MR and a decrease in platelet activity in CKCS with MR. This study included 101 clinically healthy dogs > 1 year of age: 15 control dogs of different breeds and 86 CKCS. None of the dogs received medication or had a history of bleeding. The PFA-100 evaluates platelet function in anticoagulated whole blood under high shear stress. Results are given as closure times (CT): the time it takes before a platelet plug occludes a hole in a membrane coated by agonists. The CT with collagen and adenosine-diphosphate as agonists was similar in control dogs (median 62 seconds; interquartile interval 55-66 seconds) and CKCS with no or minimal MR (55; 52-64 seconds). The CT was higher in CKCS with mild MR (regurgitant jet occupying 15-50% of the left atrial area) (75; 60-84 seconds; P = .0007) and in CKCS with moderate to severe MR (jet > 50%) (87: 66-102 seconds; P < .0001). CKCS with mild, moderate, and severe, clinically inapparent MR have decreased platelet function. The previous finding of increased platelet reactivity in nonthrombocytopenic CKCS without MR could not be reproduced with the PFA-100 device.  相似文献