A histological survey was made of the canes of 5 raspberry genotypes inoculated in the field and greenhouse with E. veneta. Acervuli bearing conidia developed on all genotypes and hyphae penetrated the cortex, polyderm and phloem, inducing extensive cell divisions, utilizisation of starch reserves and deposition of suberin and lignin-like materials in these tissues. The results indicate that the polyderm was invaded via the passage cells at an early stage in its development. Phloem fibre cells surrounded by lignified middle lamellae were rarely infected, but since the fibre bundles did not form a complete sheath around the vascular tissues, hyphae spread between the bundles to invade the phloem in all genotypes. The deposition of suberin and lignin-like materials in host cells in the cortex, phelloid cells of the polyderm and phloem partially restricted the spread of mycelium.