摘要:

ABSTRACTBrown rot (Pseudomonas solanacearum[Smith] Smith) infection of 5% or less was found in potatoes from some fields in Southern Sweden at about 56° N in the years 1972 and 19732). The fields were irrigated with water from small streams. The pathogen has been isolated from a wild host,Solanum dulcamara, growing at the water's edge in one of the streams. The wild host is perennial and bacteria can overwinter in this host. Overwintering also occurred in artificially infectedS. dulcamaraat 59° N. No overwintering in soil has hitherto been demonstrated, in spite of experiments with artificially infested soil. Infections have probably originated from imported potatoe

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1976.tb01546.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACTAs it is difficult to detect ring rot in its latent form as well as in badly decayed tubers and in potato haulm, a diagnostic technique has been developed. With the help of a Turmix blender and a little water, a suspension is made of the suspected material. The suspension is inoculated into eggplants. Gram‐staining of bacteria in sap from petioles of leaves showing symptoms is used to confirm the diagnosis. Some results obtained with this method applied on potatoes and potato haulm are describe

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1976.tb01547.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACTClonal selection with associated clinical tests and based on stem cuttings as the initial propagative material has been successfully adopted as a method of producing nuclear stocks of potato varieties free from certain important viruses, fungi and bacteria. The maintenance of health of such nuclear material during the subsequent period of multiplication to commercial quantities, however, has emphasized that gaps in our knowledge of the epidemiology of the diseases caused by these organisms exist and require investigation, so that clonal selection programs can make a maximum contribution to crop improvement.La sélection clonale assortie de tests cliniques, basés sur le bouturage par prélèvement sur tiges pour le matériel initial de reproduction, a été adoptée avec succès pour la production de stocks nucléaires de variétés de pommes de terre indemnes de certains virus, champignons et battéries importants. Les difficultés rencontrées dans le maintien d'une qualité sanitaire élevée de ce matériel nucléaire, pendant la phase de multiplication précédant la commercialisation, ont révélé les lacunes qui subsistent dans la connaissance épidémiologique des différents org

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1976.tb01548.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACTBased on the time that symptoms of blackleg become evident in the field and the various ways of inoculation, it is concluded that the spread of symptom expression is due to the depth at which the bacteria penetrate into the interior of the tubers. Moreover, it is demonstrated that it is not the closed lenticels which prevent penetration, but the absence of a waterfilm in the intercellular spaces of the tuber tissue.

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1976.tb01549.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACTTechniques in use for evaluating reaction of potato selections to wart disease are described. Races of potato wart similar to European Races 1, 2 and 8 have been detected in Newfoundland. To enable the results from potato wart investigations carried out in different countries to be compared, standard test procedures and an agreed series of differential varieties must be introduced.

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1976.tb01550.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACTResearch includes studies on physiology of germination of the causal agent, infectivity parameters, and systemic chemotherapeutants. Germination is studied with plant and fungal extracts, plant exudates and soil leachates. Sporangia are not found to respond readily to exogenously applied chemicals. Maturity appears to be hastened under incubation with plant products. Inoculum density, sporangial age, temperature and irrigation are studied for their influence on infection. Infection appears to be less dependent on external influences, and more dependent on internal timing mechanisms. Tomato varieties tested are found to be susceptible. European races 1, 2 and 8 are used in comparative studies. Germination and infectivity are studied to throw light on possible eradication mechanisms. Chemical control is studied with systemic fungicides. To date, no control is promised. Techniques have been developed to assay germination by secondary fluorescence, and to examine large numbers of soil samples by flotation.

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1976.tb01551.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACTInoculation of seed tubers withErwinia carotnvora(Jones) Bergey et al. var.atroseptica(van Hall) Dye before planting resulted in early death (especially with sprouted seed), blackleg stems and decreased yields. Apical inoculations had most, and stolon inoculations the least, effect on growth and yield. Even plants without blackleg symptoms were more stunted and had fewer stems than plants from uninoculated seed. Rotting of seed tubers often stopped in dry weather and started again later, probably caused, or assisted by, insects breaching the wound barrier.Many other organisms can also rot seed tubers includingPhytophthora erythrosepticaPethybridge (pink rot),Fusarium spp. (dry rot),Verticillium spp. (wilts) andRhizoctonia spp. (black scurf).The bacteria have been shown to spread along rows underground and to different stocks within the same field, presumably in air, but season to season spread by the potato digger has not been demonstrated.

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1976.tb01552.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1976.tb01553.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACTPropagation of potato stocks by the stem cutting method has produced crops almost entirely free from infection with the soft rot coliform bacteria,Erwinia carotovora(Jones) Bergey et al var.atroseptica(Hellmers et Dowson) Dye andE. carotovoravar.carotovoraDye. However, low levels of re‐infection have occurred and evidence indicates that a source of the organisms was infected insects. Air‐borne spread of bacterial aerosols generated by raindrop impaction on infected stems might also result in healthy stocks becoming re‐inf

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1976.tb01554.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1976.tb01555.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY