symbiont-mediated disruption of host anatomical structure symbiont-mediated occlusion of host xylem https://github.com/geneontology/go-ontology/issues/24127 biological_process occlusion by symbiont of host xylem The process in which an organism reduces the flow of fluid within the host xylem, the tissue in plants that carries water and nutrients up from the roots to the shoot and leaves. The host is defined as the larger of the organisms involved in a symbiotic interaction. GO:0052112