Abstract
Collar infection of E. marginata (jarrah) by P. cinnamomi is associated with localized ponding, and results in substantial losses of seedling jarrah from rehabilitated bauxite mines in Western Australia. A preliminary trial established in winter on a rehabilitated mine indicated that zoospores of P. cinnamomi were able to infect the collars of jarrah through unwounded periderm tissue. The trial also indicated that the pathogen was able to colonize the tissue without producing or eliciting lesions. A more detailed study was set up to examine this apparent biotrophic growth. The second trial, also conducted in a rehabilitated mine, involved inoculating jarrah plants with P. cinnanwmi in winter or spring, with three harvests at 3 month intervals. Stomatal conductance, xylem pressure potential, height and diameter data were collected regularly.