摘要:

The climatological conditions for attack of late blight caused byPhytophthora infestansvary considerably in different parts of Sweden. This is due to the fact that the country is long from south to north covering 14 degrees of latitude from 55 to 69°. One important factor for blight development in Sweden is that potato production is dominated by cultivars susceptible toP. infestans.Approximately 80% of table potatoes are of cvs Bintje and King Edward VII. Cultivars with race‐specific resistance such as Bellona, Ukama and Provita are attacked in the whole country. During recent years, many experiments have been carried out to investigate possible reductions in the usage of chemical agents for late blight control. These experiments include choice of fungicide, number of applications, dose rates and treatments according to blight warning syste

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1991.tb00453.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

A project has been undertaken in Switzerland to reduce the number of applications of fungicides to potato by a reduction of late blight incidence and disease pressure as well as by providing reliable and precise spraying recommendations against blight. We try to achieve this aim by combining different elements: (1) to delay and to impede disease progress, it is planned to promote less susceptible potato cultivars and to reduce the number of primary foci by advising seed potato growers to protect their crops more carefully; (2) the data of about 20 weather stations are utilized to test different forecasting systems; (3) these (theoretical) indications on the appearance of the disease are complemented by extensive monitoring of real late blight occurrence in the field; (4) the late blight susceptibility of all cultivars grown in Switzerland is being assessed by special trials. From the combination of all this information, spraying recommendations will be formulated according to regions and cultivars.

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1991.tb00454.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

In 1988 and 1989 bacterial diseases of potatoes in Central Anatolia were investigated by utilizing the EC method for the detection of ring‐rot bacterium (Clavibacter michiganensisssp.sepedonicus) and using selective medium. 91 samples containing 200 tubers from commercial and farmers’ stores in Central Anatolia were tested for the presence ofC.m.sepedonicusand about 50 tubers of each sample were also tested for the presence of soft‐rot erwinias. Five different bacteria that cross‐reacted withC.m.spedonicusantisera were isolated from heel‐end extracts. All cross‐reacted bacteria differed fromC.m.sepedonicusmorphologically and none of them was pathogenic on eggplant.C.m. sepedonicuswas not detected, butErwinia carotouorassp.carotouoraandErwinia carotovorassp.atrosepticawere present in 7 and 17% of the samples r

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1991.tb00455.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Whole wheat grains impregnated with 0.02, 0.05 and 0.2% sodium fluoroacetate, and 2% zinc phosphide, were offered to series of single caged individuals ofMicrotus guentheriandMeriones tristrami.In most cases the sodium fluoroacetate treated baits were well accepted by both species. The acceptance of the zinc phosphide‐treated bait was partial in all the series tested. The approximate LD50 ranges of sodium fluoroacetate are between 0.24 and 0.43 mg kg−1forM. guentheri, and, perhaps, for the jirds too, and for zinc phosphide—between 32.6 and 58.8 mg kg−1forM. tristrami, and a similar value, more or less, forM. gu

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1991.tb00456.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

During 1983–1989 about 1,200 infested plots in the Czech republic were investigated for the occurrence of new pathotypes of the potato cyst nematodes (PCN)Globoderu rostochiensisandG. pallida.Only eight populations of the pest were suspected of containing another pathotype than Ro1. Glasshouse pot trials were performed with those eight natural populations, two populations of Ro1, 10 potato cultivars resistant to Ro1 and 10 cultivars resistant to more pathotypes,G. pallidaincluded. The multiplication rates (Pf/Pi) showed that four of the PCN populations were probably mixtures, with pathotype Ro1 prevailing. Three populations were suspected of containingG. pallida, but their morphological characters corresponded only withG. rostochiensis.One population corresponded with pathotype Ro5. The extent of the occurrence of pathotypes or virulence groups different from Ro1 can be estimated at 0.3–0.4% of infested pl

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1991.tb00457.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The concept of physiological specialization as used in plant pathology has limitations for consistent use in plant quarantine. Some details of the concept and its application in quarantine are discussed. A structured approach is developed and proposed for evaluation of variations in pathogens as a valid scientific argument in quarantine decision‐makin

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1991.tb00458.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1991.tb00459.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1991.tb00460.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1991.tb00461.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1991.tb00462.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY