摘要:

SummaryThe intersterility groups of 127 pure cultures ofH, annosumcollected from different host trees in 12 mountain areas in Greece were identified. The F group commonly caused butt rot on the fir speciesAbies cephalonicaandAbies borisii regis. It was the only type ofH. annosumfound in pure fir forests. The P group caused serious root rot inpinus sylvestrisstands in north‐eastern Greece. In more southern mountain areas it often colonized stumps ofpinus nigrabut seldom killed this tree species. The S group was found in natural forests ofPicea abiesin northern Greece, causing butt rot of spruce. In mixed forests, the intersterility groups ofH. annosumwere found relatively often in stumps of tree species other than their main hosts, although some host preference seemed to occur also in stump colonizatio

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1996.tb00705.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

SummaryDischarge and germination of ascospores ofHypoxylon mediterraneum(=Biscogniauxia mediterranea(De Not.) O. Kuntze) were studied. Discharge and germination of ascospores depend on the presence of water or high relative air humidity. Ascospores are ejected from stromata in forest for most of the year following periods of high precipitation.H. mediterraneumascospores germinated under a wide range of biotic and abiotic conditions. The optimal temperature for germination was 35°C, but 25 and 30°C were still favourable, while 20 and 40°C reduced germination. Ascospores kept at 5°C were able to germinate after short exposure to temperatures ranging from 20 to 35°C. Germination rate depended on the ascospore density inin vitroexperiments, and was highest at 106ascospore/ml.Tissues of some host plants greatly increased germination rate.In vivo, ascospores germinated better on wounded axillary tissues than on unwounded

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1996.tb00706.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

SummaryTwo root‐rot fungi,Rigidoporus lignosusandPhellinus noxiusare the causal agents of severe damage in Ivory Coast rubber tree (Hevea brasiliensis) plantations. Mathematical investigations were made using data from a previous 6 year long epidemiological survey. Modelling of spatial spread of the pathogens and mortality of the infected trees, lead to simulations of the quantitative evolution vs. time of root diseases. The theoretical kinetics obtained revealed intra‐ and interspecific variability among the studied stands with respect to the damage caused. Using this model, different phytosanitary scenarios were simulated in relation to the density of the initial inoculum, the control measures, the specificity of the fungicide, the efficiency of the treatment, and the optimal time for application. Their influence on root‐disease dynamics was quantified. The characteristics of the model, its applicability in plantations and its use in predicting disease or stand development are disc

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1996.tb00707.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

SummaryGenomic DNA from 81 isolates ofGremmeniella abietinacollected from eleven plantations each ofPinus sylvestrisandPinus contortain northern Sweden was studied using RAPD markers. The DNA variation between and within populations and the race and type distribution ofG. abietinapopulations, causing symptoms similar to those of the North American race, were studied. The degree of genetic similarity was greater amongG. abietinaisolates from the same geographical areas than among isolates from different geographical areas, regardless of whether they were isolated fromP. sylvestrisorP. contorta. RAPD variation was greatest in the central parts of northern Sweden, suggesting that sexual reproduction has been somewhat more important there than further north or south. Only the RAPD fragments characteristic of the EU race ofG. abietinawere found in the material tested. The RAPD pattern described as characteristic of the northern type within the EU race was identified in 62% of the isolates. Divergence from the expected profile was due to differences in occurrence of fragments OPA12‐1400 and 12‐1500. This indicates that this part of the RAPD profile cannot be treated as diagnostic for the northern type. A conclusion of practical importance is that there is a considerable risk ofG. abietinaspreading from infectedP. contortaplantations to adjacent areas with indigenousP. sylvestrisregeneration, and vice versa, owing to the indicated lack of host‐specificity of the pathogen. It is possible, however, that host‐specific strains exist, but do not differ in their RAPD p

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1996.tb00708.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY