Identifying marri canker disease

A severe canker disease has been contributing to decline in marri (Corymbia calophylla) for some years now. Cankers are a symptom caused by the death of areas of bark and the cortex tissue below that, and are caused by the plant pathogen Quambalaria coyrecup. The canker is present on trunks, branches and twigs of trees of all ages. Canker disease occurs on marri across the natural range of this tree in south west WA. It also affects amenity-planted red flowering gum (C. ficifolia). Once canker symptoms are evident, trees do not appear to be able to recover, and given the large number of infected trees, the future health of marri in south west WA is of serious concern