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1.
G. Van Voorst E. A. Van Os J. C. Zadoks 《European journal of plant pathology / European Foundation for Plant Pathology》1987,93(4):195-199
Tomatoes were grown in a greenhouse by nutrient film technique (NFT). They were inoculated withPhytophthora nicotianae either by direct inoculation of roots or by adding fungal spores to a container with recirculating nutrient solution. In the first case, the resulting epidemic seemed to be polycyclic, in the second case monocyclic. In both cases, inoculum freely circulated through the NFT system and was present in the nutrient solutions for at least 6 days after inoculation.Samenvatting Kastomaten werden gekweekt met behulp van voedingsfilmtechniek. Zij werden geinoculeerd metPhytophthora nicotianae hetzij door directe besmetting van wortels, hetzij door een sporensuspensie toe te voegen aan het voorraadvat met voedingsoplossing. In het eerste geval leek een polycyclische epidemie te volgen. In het tweede geval ontstond een monomcyclische epidemie. In beide gevallen werd schimmelinoculum door het gehele gotensysteem rondgepompt. Inoculum bleef gedurende tenminste 6 dagen na inoculatie aantoonbaar in de voedingsoplossing. 相似文献
2.
Effects of crop management patterns on coffee rust epidemics 总被引：1，自引：0，他引：1
The effects of crop management patterns on coffee rust epidemics, caused by Hemileia vastatrix , are not well documented despite large amounts of data acquired in the field on epidemics, and much modelling work done on this disease. One main reason for this gap between epidemiological knowledge and understanding for management resides in the lack of links between many studies and actual production situations in the field. Coffee rust epidemics are based on a seemingly simple infection cycle, but develop polycyclic epidemics in a season and polyetic epidemics over successive seasons. These higher-level processes involve a very large number of environmental variables and, as in any system involving a perennial crop, the physiology of the coffee crop and how it affects crop yield. Crop management is therefore expected to have large effects on coffee rust epidemics because of its immediate effect on the infection cycle, but also because of its cumulative effect on ongoing and successive epidemics. Quantitative examples taken from a survey conducted in Honduras illustrate how crop management, different combinations of shade, coffee tree density, fertilization and pruning may strongly influence coffee rust epidemics through effects on microclimate and plant physiology which, in turn, influence the life cycle of the fungus. We suggest there is a need for novel coffee rust management systems which fully integrate crop management patterns in order to manage the disease in a sustainable way. 相似文献
3.
Delphine?Allorent Serge?SavaryEmail author 《European journal of plant pathology / European Foundation for Plant Pathology》2005,113(4):329-341
In this review, available knowledge on angular leaf spot (ALS) of bean, caused by Phaeoisariopsis griseola, is analysed and synthesised. This is done through a systems-analytical approach, and successive flowcharts of the system,
in order to identify knowledge gaps and guide further research. Six connected sub-models of the ALS monocycle are used as
a framework: lesion establishment, lesion extension, defoliation, sporulation, spore liberation, and spore deposition. Each
of the sub-models enables the linking of processes to various effects of environmental (physical and host) factors. Disease-induced
defoliation is one feature of the pathosystem, leading to a depletion of infectious tissues from the canopy, which are transferred
to the ground. Consequences of defoliation may include: strong reductions of the amount of inoculum and of vacant sites in
the canopy, limited maximum disease severity, and progressive accumulation of inoculum below the canopy, which may become
important a later stage of disease epidemics. These elements are hypothesised to explain the typical behaviour of ALS epidemics
in the field, especially late onset, high apparent rate of disease increase, and low level of terminal disease severity in
the standing canopy. Epidemiological consequences of lesion expansion, sporulation, and survival of spores deposited onto
the canopy are other knowledge gaps in this pathosystem. 相似文献
4.
Effects of radiation,especially ultraviolet B,on conidial germination and mycelial growth of grape powdery mildew 总被引：5，自引：0，他引：5
L. Willocquet D. Colombet M. Rougier J. Fargues M. Clerjeau 《European journal of plant pathology / European Foundation for Plant Pathology》1996,102(5):441-449
Conidia ofUncinula necator inoculated on vine leaf disks were exposed to different irradiation conditions during various combinations of irradiation periods. In controlled experiments at constant leaf temperature spore germination and mycelial growth were negatively affected by the UV B doses, irrespective of the exposition duration. In semi-controlled condition experiments, conidia were exposed to shaded, sunny and sunny without UV B radiation conditions. Shaded conditions were always more favourable to spore germination and mycelial growth than sunny conditions. Under two different ranges of temperature (20–24 and 26–31 °C for shaded conditions), the effect of radiation on germination and mycelial growth differed. Thus, the effect of radiation on spore germination and mycelial growth seems to be affected by temperature. In general, radiation effects increased as the number of exposition periods increased, indicating that both spore germination and mycelial growth were reduced, but not totally stopped by the different exposures. Germination was most affected by exposures applied just after inoculation, whereas mycelial growth was most affected by exposures applied one day after inoculation. These results indicate that radiation is an important factor to consider for a better understanding of the relationships between climate and grape powdery mildew epidemics. 相似文献
5.
段晖 《中国林学(英文版)》2000,(2)
研究了以单环单萜烯烃为原料 ,CD分子筛为催化剂 ,歧化合成对 异丙基甲苯的工艺条件 ,并对对 异丙基甲苯进行了谱图解析 .研究结果表明CD催化剂具有制备简单、价格低廉、回收简单、没有污染和腐蚀性等特点 .而且单环单萜烯烃来源于工业副产品 ,大大降低了生产成本 相似文献
6.
I. Sache J. C. Zadoks 《European journal of plant pathology / European Foundation for Plant Pathology》1995,101(4):431-439
In controlled near-optimum conditions (18 °C), monocyclic sporulation capacity and spore infection efficiency were assessed for faba bean rust on the first and second leaves of field bean. After a latency period of 8–10 days, lesions sporulated duringc. 50 days. Spore production on the second leaf,c. 9×104 spores per lesion, was two times as high as spore production on the first leaf. Infection efficiency was similar for both leaf layers, with a mean value of 0.11 lesion per inoculated spore. Infection efficiency decreased strongly when spores originated from mother lesions older than 20 days. Three life-table statistics (the net reproduction numberR
o
, the mean generation timeT
g
, and the maximum relative growth rater
max
) were calculated.R
o
was larger andT
g
was longer for the second than for the first leaf, butr
max
was nearly the same for both leaf layers (0.31–0.33 day–1).r
max
was compared with the exponential growth rater measured in a field experiment. From the difference between the two rates, the fraction of inoculum lost in field conditions was estimated at 0.54–0.94. The life-table statistics were also compared to those of other legume rusts, and implications of life-table analysis for comparative epidemiology were discussed. 相似文献
7.
S. Savary 《European journal of plant pathology / European Foundation for Plant Pathology》1987,93(1):25-31
The effects of plant development and leaf age on the infection efficiency (IE), the latency period (LP) and the sporulation intensity (SP) of groundnut rust were studied using detached and attached leaflets of a highly susceptible groundnut cultivar. The results indicate a decrease ofIE with increasing leaf age and an increase ofLP with increasing leaf age and development stage. A significant effect of detachment onIE was found. However, experiments on both detached and non-detached leaflets resulted in the same, general conclusions. The observed reduction ofIE and lengthening ofLP suggest that further studies would profitably distinguish epidemiologically different layers in the host canopy.Samenvatting De invloed van het ontwikkelingsstadium van de plant en van de leeftijd van het blad op de infectie-efficiëntie (IE), de latentieperiode (LP) en de sporulatie-intensiteit (SP) van aardnootroest werd onderzocht bij een zeer vatbare aardnoot-cultivar aan wel en niet afgesneden deelblaadjes. De resultaten laten een afname zien vanIE bij toenemende bladleeftijd alsmede een toename vanLP met de toename van bladleeftijd en ontwikkelingsstadium. Het effect van het afsnijden van de deelblaadjes opIE was significant, maar proeven met wel en met niet afgesneden blaadjes leidden tot dezelfde algemene gevolgtrekkingen. De waargenomen afname vanIE en verlenging vanLP doen vermoeden dat voortgezet onderzoek een nuttig onderscheid zal kunnen maken tussen in epidemiologische zin verschillende bladlagen van het gewas. 相似文献
8.
Yael Rekah D. Shtienberg J. Katan 《European journal of plant pathology / European Foundation for Plant Pathology》2001,107(4):367-375
Fusarium oxysporum f. sp. radicis-lycopersici the causal agent of crown and root rot in tomato comprises two overlapping separate phases: monocyclic and polycyclic. Oversummering inoculum is the source of primary infection (the monocyclic phase) and the spread from plant to plant via root-to-root contact is the source of the secondary infection (the polycyclic phase). In the present work, relationships between initial inoculum density, population dynamics of the pathogen in the root zone of diseased plants, and disease onset were studied. For the monocyclic phase, 55.1% of the variance of disease onset was attributed to the rate of pathogen proliferation in the root zone of plants, and only 12.8% of the variance was attributed to the amount of initial inoculum density. For the polycyclic phase, disease onset was not related to either initial inoculum density or the rate of pathogen proliferation in the root zone. At disease onset, the inoculum density of the pathogen in the root zone of plants infected from oversummering inoculum reached an average of 4.08 log cfu g soil–1. The inoculum density of the pathogen in the root zone of plants infected by their diseased neighbors was 3.23 log cfu g soil–1. A large variation in pathogen proliferation rate in the root zone was found among individual plants, suggesting that differences in the level of soil suppressiveness may occur not only between fields, but even in the same field over short distances. 相似文献
9.
毛竹枯梢病侵染循环与病原菌生活史的研究 总被引：8，自引：0，他引：8
毛竹枯梢病在福建以病竹竹筒内菌丝体及1～3级病侧枝的子实体越冬,翌年4月底至5月初产生大量的子囊孢子,借风雨传播,从当年新竹展枝放叶期的1～3级侧枝节叉处形成的自然伤口侵入,潜育期1～3个月,有的长达1～2年。7～8月高温干旱季节为发病高峰期,10月底基本停止扩展,11月至翌年2月为病菌越冬期。毛竹枯梢病的侵染循环属于多侵染点一次性侵染的单循环病害类型。自然条件下,竹喙球菌在病竹侧枝节又处产生单生或混生的子囊壳和分生孢子器,其生活周期属于真菌的完全发育循环类型。 相似文献
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