Abstract
Twenty, black stain root disease infected Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) from the Oregon Cascade and Coast ranges were dissected; macroscopic and microscopic patterns of fungal colonization are described. Ceratocystis wageneri Goheen et Cobb colonized secondary xylem, disrupting xylem transport. Histopathological studies revealed that the tracheid-limited pattern of colonization exhibited by this fungus is unique among Ceratocystis wilt pathogens. Axial colonization by hyphae was confined to xylem tracheids and radial development of mycelia in ray tracheids was limited. Parenchyma and cambial necroses did not result from direct hyphal attack. Living host cells, although not invaded, were responsive to hyphal attack of adjacent functional xylem. Secondary phloem was never invaded by hyphae, but some dysfunction was evident. Host responses to infection were unsuccessful in curtailing the spread of the pathogen.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
