摘要:

AbstractDieback of poplar and willow, grown in short‐rotation forestry plantations, was shown to be a result ofPseudomonas syringaeinfections in combination with freezing stress. Bacteria isolated from damaged poplar and willow trees at several sites in Sweden, identified asP. syringae, showed ice nucleationactive (INA) properties in laboratory tests. To confirm the effect of bacterial infection, five differentP. syringaeisolates were reinoculatcd into stems ofSalix viminalis, S. dasycladosandPopulusspp. in the greenhouse before application of sub‐zero temperature stress. Subsequent dieback of the shoots was observed. It is concluded thatP. syringaeis a Potentiall severe pathogen of willow and pop

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1994.tb00824.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractIn culture,Rosellinia desmazieresii, the agent of a ring‐dying disease inSalix repens, which can penetrate intact periderm surfaces in its host, produced a range of cell‐wall‐degrading enzymes. These included esterases that may be important in the depolymerization of suberin. Slow breakdown of suberin by this fungus was demonst

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1994.tb00825.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe ascomycetePloioderma hedgcockiiis unique in speculating; on living, as well as on dead needle tissues. The fungus was examined in green and dead needles ofPinus elliottiivar. elliottii using light microscopy. Teleomorph and anamorph stromata originated from sub‐hypodermal host tissue. In green needles, the hypnae where restricted to tissues outside the endodermis. The mesophyll cells adjacent to stromata showed abnormalities; the mesophyll distal to the stromata showed no symptoms despite heavy colonization by intercellular hyphae. In dead needles, all tissues, with the exception of vascular tissues, where colonized by inter‐ and intracellular hyp

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1994.tb00826.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe mycorrhizas of Sitka‐spruce seedlings propagated in two bare‐root nurseries and one container nursery in Ireland are identified and compared. In the bare‐root nurseries,Piceirhiza horti‐inflatawas the most frequent mycorrhizal association during the first year of growth but appeared to be replaced byHebelomasp. andAmphinema byssoidesin 2‐year‐old seedlings. There was a greater diversity of mycorrhizas on container‐grown seedlings which includedThelepbora terrestris, Hebelomasp. andPicei

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1994.tb00827.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractRoot and soil samples fromEucalyptusandPinus plantationstaken during routine surveys of South African forestry areas during 1990–1992, yielded various species ofPythiumandPhytophthora. These include three species ofPhytophthoraand 20 species of Pythium. Six of thesePythiumspecies have not previously been recorded in South Africa. The pathogenicity of thePythiumandPhytophthoraspp. collected during the surveys was tested on establishedEucalyptus fastigataand a clone ofE. grandi

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1994.tb00828.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractScots pines (Pinus sylvestris) in a 20‐year‐old plantation in northern Vermont, USA, were inoculated with the pinewood nematode (Bursaphelenchus xylophilus) in 1987. To determine how longB. xylophiluswould survive after inoculation, the trees were periodically observed and sampled for the nematode up to the end of 1993. The nematode was still found to persist in living, healthy‐appearing pines 6 years after inocul

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1994.tb00829.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractIn Vitroantagonism of three root‐disease pathogens,Phellinus weirii, Heterobasidion annosum, andArmillaria ostoyaebyUlocladium botrytis(Preuss) is discussed. On solid medium, areas of inhibition were characteristic of antagonism, whereas, in liquid medium, antagonism resulted in the reduction of the colony dry weights of the pathogens. The antagonistic effect ofU. botrytiswas fungistati

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1994.tb00830.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe recently developed needle‐trace method (NTM) was successfully used to verify retrospectively the occurrence of a well‐documented needle‐cast epidemic caused byLophodermella sulcigenain the 5‐year period of 1977–1981 in a stand ofPinus s

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1994.tb00831.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractA comparative study by light and scanning‐electron microscopy of fine and coarse roots from healthy and declining oaks demonstrated a progressive deterioration of fine roots and mycorrhizal systems on mature trees in decline. Histopathological events such as infection of cortical and vascular root tissues by parasitic fungal hyphae leading to the impairment of woody roots are described. Distinct disease symptoms such as necrotic lesions on small diameter roots and callussing wounds on coarse roots are documented, supporting the hypothesis thatPhytophthoraspp. are involved in oak declin

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1994.tb00832.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractYellow cedar (Chamaecyparis nootkatensis) is a valuable tree species that is experiencing an extensive forest decline on over 200000 ha of unmanaged forest in southeast Alaska. Biotic factors appear secondary and some abiotic factor is probably the primary cause of this naturally occurring decline. A warming climate, which coincided with the onset of extensive tree mortality about 100 years ago, may have triggered one of the possible abiotic causes such as freezing damage and/or soil toxicity.

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1994.tb00833.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY