摘要:

Since 1982, outbreaks of stem blight caused byPseudomonas cichoriiare sometimes found in greenhouse‐grown chrysanthemums in The Netherlands. In this study, 13 Dutch chrysanthemum isolates and, for comparison, six from other origins were biochemically, serologically and pathologically characterized. All isolates were biochemically homogeneous in most of some 40 tests. Different serotypes were observed, which were not host or virulence‐correlated. After inoculation into cut and potted chrysanthemum, endive and chicory,P. cichoriiisolates were found to be non‐host‐specific. Isolates showed differences in virulence after inoculation into potted chrysanthemum. For five isolates, disease development at high humidity (85–95% RH, 18°C) was more than 100% greater than at low humidity (55–70% RH, 18°C). Using a selective medium and immunosorbent dilution plating (ISDP),P. cichoriicould be isolated from symptomless leaves and soil from nurseries where the disease was observed and from soil of a disease‐free nursery. ISDP did not significantly increase the recovery of the pathogen. It was concluded that: (a)P. cichoriiis an opportunistic pathogen; (b) epidemic infections of stem blight are due to a combination of high humidity, higher temperatures, high plant density and use of very susceptible cultivars; (c) control measures should concentrate on preventing t

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00045.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Une nouvelle maladie, la pourriture sèche des racines et du collet, se manifeste chez les agrumes en Grèce et surtout en Crète, provoquant des dégâts importants. Les jeunes sujets de moins de 5 ans ainsi que les arbres en production de 15–25 ans se sont montrés les plus sensibles. La maladie se manifeste fortement au cours de trois périodes: au printemps (pleine floraison), en été (températures élevées) et en automne (début de la maturité des fruits). Les symptômes les plus fréquents sont l'apoplexie et l'hémiplégie. Les porte‐greffeCitrus aurantium, Poncirus trifoliataet citrange Troyer sont également affectés. Trois espèces deFusariumont été isolées à partir des racines d'arbres atteints (Fusarium solani, F. proliferatumetF. sambucinum) dans la proportion de 7:1,5:1. Un essai d'inoculation artificielle d'arbres en pots a confirmé que ces champignons sont capables de provoquer la maladie, surtout en présence de stress hydrique, de fumure excessiv

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00046.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

The avoidance of curative or eradicative use has been recommended as one element in the strategy for combating the development of resistance against acylalanine fungicides. The concepts involved are discussed in relation to the mechanisms of fungicidal action and resistance development. This element in the strategy requires a more critical reformulation, and this in turn will depend upon new research and experience with resistance development. Practical and economic factors encountered in applying fungicide resistance management strategies are mentioned.

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00047.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

To investigate testing procedures for assessing the reproduction of potato cyst nematodes (PCN) on potato cultivars, and to minimize variation in results, trials were done jointly for 3 years at two UK National Listing test centres (DANI in Northern Ireland, DAFS in Scotland). Test clones comprised susceptible, resistant and ‘partially resistant’ cultivars. The factors under investigation included the effect of season, site, location, temperature, PCN population, inoculation method, pot size, hatch rates and methods of assessment of reproduction. Standard procedures are recommended for testing potato cultivars for resistance to

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00048.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Because of increasing government fees, the chemical industry in The Netherlands has shown interest in taking over the performance of any additional field trials required for obtaining the registration of pesticides. A system is described whereby the chemical industry arranges and performs such trials under the surveillance and supervision of the Plant Protection Service, the Service retaining control of standards, the right of evaluation, and the final assessment of efficacy. Areas of responsibility are defined, suggestions for the future are given and the system is seen as developing satisfactorily.

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00049.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00050.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00051.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00052.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00053.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00054.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY