摘要:

AbstractThe incidence of root disease was determined on Norway spruce in a mixed stand of spruce and fir near Alpirsbach (Northern Black Forest), Germany. Fifteen most symptomatic spruce were selected in each of two plots that had been limed with Mg‐containing lime termed “Hüttenkalk”, or nonlimed, in a previous trial to alleviate symptoms of yellowing and premature needle loss. No relationships were found between persistence of yellowing and needle loss on either plot and incidence ofH. a

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1991.tb00770.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractPhloem Necrosis of the trunk of the rubber tree in Ivory Coast: 1. Symptomatology and biochemical characteristics. External and internal symptoms of this disease affecting the lower part of the trunk ofHevea brasiliensisare described. Data on necrosis spread in the tissue and on comparative biochemical characteristics of latex are given and discussed.

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1991.tb00771.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractPhloem Necrosis of the trunk of the rubber tree in Ivory Coast. 2. Etiology of the disease. Numerous experiments were performed in order to identify the causal pathogen of rubber tree Phloem Necrosis. Trials of control by fungicides and bactencides, of identification of the microorganisms isolated from decayed tissues, of transmission from diseased to healthy trees and also, microscopic observations of necrotic phloem samples, all failed in practice. However, symptomatology and epidemic spread in plantation suggest a pathological cause of this disease.

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1991.tb00772.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractTwo fungus and one bark beetle species were introduced into Scots pine phloem. The phenolic composition of the induced reaction zone in the phloem, studied by two dimensional thin layer chromatography, greatly differed from that of the uninjured phloem. The concentration of three compounds increased, one of them considerably, while the concentration of four others decreased. These modifications were the same irrespective of the nature of the aggressor.

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1991.tb00773.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractEight clones ofFraxinus excelsior, one clone ofF. americanaand one clone otF. pennsylvanicawere tested for their susceptibility to bacterial knot disease by artificial inoculations. Parametric and non‐parametric methods of statistically analysing their resistance were compare

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1991.tb00774.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractAlthough the suberized rhytidome and phellem of Norway spruce bark appeared to be the strongest barriers against penetration byHeterobasidion annosum, artificial inoculations on standing trees showed that the living phelloderm and phloem bark were also able to contain the fungus. Thickened cell walls and excretions in the lumen of necrotic cells, as well as morphological changes in the infecting hyphae, indicated that this protection is of both mechanical and chemical character. Rate of wound pcriderm formation was correlated to bark thickness and tree age.

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1991.tb00775.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractMorphological structures of the teleomorphous and anamorphous stages of the ascomyceteLophodermium piceaehave been studied in detail. This fungal species is widely distributed and frequent on Norway spruce needles. The examination of many samples indicates that all belong to one species, namelyL. piceae.

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1991.tb00776.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe effects of ammonium sulphate and sodium nitrate onPinus sylvestrisseedlings inoculated withPaxillus involutusandSuillus bovinuswere investigated. Weekly fertilization (26 weeks) positively affected the plant dry weight, but inhibited the mycorrhizal formation and decreased the root length/weight ratio. Ammonium treatments affected the seedlings more positively and the mycorrhizas more negatively than nitrate did. The effects on seedlings inoculated withP. involutuswere more pronounced than on those inoculated withS. bovinus. The possible mechanisms of the effects of nitrate and ammonium on mycorrhizas are discussed.

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1991.tb00777.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractPinus sylvestrisseedlings were grown in quartz sand and N, K and Mg were given in different ratios with the irrigation water. After growing season 50 % of the seedlings were inoculated with a conidial suspension ofGremmeniella abietina. The resistance of the seedlings to infection was studied by measuring the reduction of needle retention. K deficiency reduced the resistance. However, the effect of K was dependent on the amount of irradiance available in growth chamber after winter dormancy. In addition, deficient foliar K and Mg concentrations in combination, reduced the resistance of seedlings to infection.

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1991.tb00778.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe pathogenicity of an isolate ofCryphonectria cubensiswas tested in artificial inoculations onEucalyptus grandis, Psidium guajavaandSyzygium cordatmn. The isolate was able to colonize host tissue of all three species following inoculations of branch sections. It rapidly colonized the tissue of potted guava plants of the important commercial cultivar, Fan Relief and resulted in the death of a number of inoculated branches. Pathogenicity was also proven on mature guava trees in the field. An important implication of these findings is that the cultivation of guavas in South Africa could be confronted with a potentially severe disease problem in the future.

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1991.tb00779.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY