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.