Oort en het onderwijs     

J. C. Zadoks  J. Dekker 《European journal of plant pathology / European Foundation for Plant Pathology》1969,75(1-2):22-26

Summary When Oort took the chair of plant pathology in 1949 his teaching included virology and nematology in addition of fungal and bacterial diseases. In 1950 a chair of plant virology was founded while in 1956 a lecturer in plant nematology was added to the chair of phytopathology. Only then could Oort concentrate on fungal diseases. Oort closely followed the turbulent evolution of phytopathology and, though he surveyed a wide field, he did not hesitate to invite staff members to teach special courses. In recent years junior students had to follow courses in Introductory Plant Pathology, General Plant Pathology, Morphology and Taxonomy of Fungi, and in addition a practical course in symptom analysis and morbid anatomy. For advanced students seminars were organized, each concentrating on one topic, e.g. Resistance or Soil Borne Diseases. Moreover, the advanced students had to follow a practical course in phytopathological and pathophysiological techniques. Specialized practical courses on Epidemiology and Resistance and Physiology of parasitism were started recently. The students usually did for 3 or 6 months research work under the guidance of a staff member. A research report and a literature review on a chosen topic were obligatory for all advanced students. Oort's keen interest in teaching aids led to the accumulation of a large slide collection which contained hundreds of colour slides of disease symptoms, and to a collection of diseased plants in permanent mounts. In nearly 20 years Oort accepted and discussed over 300 research reports, about 225 literature reviews, 21 doctor's theses and examined over 700 students.  相似文献   

Chemical control of Puccinia horiana in Chrysanthemum morifolium     

R. Zandvoort  C. A. M. Groenewegen  J. C. Zadoks 《European journal of plant pathology / European Foundation for Plant Pathology》1968,74(5):170-173

Samenvatting In een aantal proeven werd nagegaan of een bestrijding vanPuccinia horiana met fungiciden mogelijk was. Een preventieve bespuiting met ferbam, zineb en spuitzwavel kon een aantasting van de roest vrij redelijk voorkomen. Met maneb, mancozeb en het mengsel van maneb met NiCl₂.4H₂O waren deze resultaten iets beter. Het mengsel van maneb met NiCl₂.4H₂O bleek, vooral bij een bespuiting korte tijd na de inoculatie, een curatieve werking te hebben. Het bleek niet mogelijk de roest door een bespuiting afdoende te bestrijden.  相似文献   

On the incubation period of Puccinia horiana     

R. Zandvoort  C. A. M. Groenewegen  J. C. Zadoks 《European journal of plant pathology / European Foundation for Plant Pathology》1968,74(4):128-130

Samenvatting De minimum-incubatietijd vanPuccinia horiana is 6 dagen. Bij 10°C is deze tijd tenminste 13 dagen. De incubatieperiode was het kortst bij 17°C en 21°C (Fig. 1). Uit een waarneming in de praktijk werd de aanwijzing verkregen, dat door een hoge temperatuur gedurende enige tijd de incubatieperiode kan worden verlengd tot tenminste 56 dagen. De roest kan op of in moerplanten overwinteren. In proeven werden aanwijzingen verkregen, dat door volledig wegsnijden van de bovengrondse plantedelen het inoculum kan worden verwijderd.  相似文献   

Verenigingsnieuws     

Dr. J. C. Zadoks 《European journal of plant pathology / European Foundation for Plant Pathology》1965,71(1):28-30

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On the dangers of artificial infection with yellow rust to the barley crop of the netherlands; A quantitative approach     

J. C. Zadoks 《European journal of plant pathology / European Foundation for Plant Pathology》1966,72(1):12-19

In the Netherlands, some barley breeders perform artificial infections with barley yellow rust in their fields to test their selections for resistance. The question has been raised wether this artificial infection of breeders fields can be justified in view of the danger of causing an epidemic. In 1962, conditions were favourable to arrive at an answer to this question. A rust survey provided the data from which the amount of rust in artificially and in spontaneously infected fields could be computed using a new, quantitative method. Artificial and spontaneous infection yielded approximately equal amounts of rust on the reference date, July 1st, 1962. In years with a severe epidemic, the total amount of spontaneously occurring rust is at least a thousandfold of the amount present in 1962, a year with exceptionally little rust. This leads us to the conclusion, that artificial infection of breeders fields does not materially contribute to spontaneous epidemics of yellow rust of barley in the Netherlands.  相似文献   

Verenigingsnieuws     

Dr. J. C. Zadoks 《European journal of plant pathology / European Foundation for Plant Pathology》1967,73(4):129-132

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An inhibitory effect of light on the infection by brown leaf rust of wheat     

J. C. Zadoks 《European journal of plant pathology / European Foundation for Plant Pathology》1967,73(2):52-54

Samenvatting Licht gedurende 6 tot 24 uur na inoculatie heeft een remmende invloed op het infectieproces met als resultaat dat weinig sporenhoopjes gevormd worden. De lichtremming vindt hoofdzakelijk plaats in een fase voorafgaand aan de penetratie. Bij routinewerk in de kas werden de resultaten belangrijk verbeterd door na inoculatie de planten gedurende 16 tot 24 uur te incuberen in volledige duisternis, uiteraard bij 100% relatieve luchtvochtigheid.  相似文献   

Smoke puffs as models for the study of spore dispersal in and above a cereal crop     

J. C. Zadoks  A. O. Klomp  D. Van Hoogstraten 《European journal of plant pathology / European Foundation for Plant Pathology》1969,75(3):229-232

Samenvatting De verspreiding van roestsporen door turbulente luchtbewegingen wordt geïllustreerd met behulp van rookwolkjes. Rookwolkjes werden geproduceerd nabij het actieve buitenoppervlak van een gerstgewas. De bewegingen van de rookwolkjes werden gefilmd. Iedere kwart seconde werd de op de film zichtbare buitenomtrek van een rookwolkje op een tekening vastgelegd (Fig. 1 t/m 10). De verplaatsing van het zwaartepunt van ieder rookwolkje kon een aantal seconden gevolgd worden (Fig. 11). De waarnemingen ondersteunen de gangbare opvattingen over de verspreiding van uredosporen binnen de gewasruimte en vanuit het gewas naar de, turbulente lucht daarboven.  相似文献   

The “Other” Gram-Negative Bacteria in Mastitis : Klebsiella,Serratia, and More     

Ynte Schukken  Matt Chuff  Paolo Moroni  Abhijit Gurjar  Carlos Santisteban  Frank Welcome  Ruth Zadoks 《Veterinary Clinics of North America: Food Animal Practice》2012

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Role of Luteinizing Hormone in Primiparous Sow Responses to Split Weaning     

L Zak  GR Foxcroft  FX Aherne  RN Kirkwood 《Reproduction in domestic animals》2008,43(4):445-450

In 45 primiparous sows, we examined endocrine, ovarian and reproductive responses to split-weaning or five injections per day of 800 ng GnRH from 18 to 21 days of lactation. There was no effect of treatment on absolute or changes in sow weight or backfat depth during lactation. Average piglet growth rates were similar among treatments except that piglets suckling split-weaned sows grew faster (p < 0.05) during days 18–21. On day 18, mean plasma LH concentrations and LH pulse frequency remained relatively stable in conventionally weaned sows but increased (p < 0.01) in response to split-weaning and GnRH. Prior to weaning on day 21, mean plasma LH concentrations remained elevated in GnRH-treated sows but had returned to control levels in split weaned sows. There was no treatment effect on preweaning LH pulse frequency noted on day 21. Weaning was associated with an increase in plasma LH concentrations in all the treatment groups. Mean plasma IGF-I remained relatively constant in conventionally weaned and GnRH sows, decreased in response to split weaning on day 18 (p < 0.02), but were elevated (p < 0.03) in split wean sows on day 21. On the day after weaning, split wean sows had more (p < 0.04) ovarian follicles ≥3 mm than conventionally weaned sows, with GnRH sows being intermediate. The wean-to-oestrus interval was reduced in split-wean sows compared with those conventionally weaned (p < 0.01), with GnRH sows being intermediate. There was no effect of treatment on ovulation rates, numbers of embryos, or embryonic survival rates. These data indicate that split-weaning of litters results in a more rapid return to oestrus after weaning and that this effect is associated with a transient acute increase in circulating gonadotrophins and earlier resumption of ovarian follicular development.  相似文献