Xylem tissues of eight pip fruit, two stone fruit and one willow cv. exhibited similar seasonal variations in susceptibility to colonisation by hyphae of Chondrostereum purpureum following monthly inoculation and incubation of cuttings in the laboratory. Xylem tissues of all hosts exhibited maximum resistance during May/June/July. Generally, susceptibility increased in spring/early summer, peaked in November and declined over late summer to autumn. During June, cv. Golden Delicious apple cuttings prevented host colonisation by immersion of hyphae in tannin-like deposits in xylem vessels. Such deposits were not observed in Nashi pear where hyphae in vessels were also severely disrupted. Hyphae of C. purpureum were bi-nucleate, contained glycogen deposits and readily penetrated starch granules and cell walls.