Cankers

Cytospora canker (Cytospora eucalypticola)

• Usually small (less than 50mm diameter) red-brown patches occur, but these can become larger.
• Dead and dying patches are mostly on tree stems, but also on branches.
• Small fruiting structures are often seen within the canker. These develop just beneath the surface and break through, splitting the bark surface. The fruiting structures appear as black to grey and sometimes white dots.
• This is a common canker, which readily colonises wounds.
• Lesions on healthy trees mostly heal over.

Caliciopsis canker (Caliciopsis pleomorpha)

• Small (less than 50mm diameter) localised cankers occur on branches or small stems.
• They can look like hail damage.
• Small cankers often occlude over.
• They are commonly seen in trees under stress, such as from defoliating insects and fungi.
• Severe cankers resulting in tree death are rare.

Endothia stem canker (Holocryphia eucalypt, formerly Endothia gyrosa)

• Dead and dying patches occur on stems or branches. They range from less than 1m to more than 4m.
• Bark at the canker site is commonly, but not always, cracked and split, with some kino exudation.
• Small orange and black fruiting structures are often seen within cankers and nearby bark.
• These often occur in trees under stress, such as from defoliation or storm damage.

Botryosphaeria canker (Botryosphaeria species, Neofusicoccum species and Fusicocum species)

• Infection can occur on twigs, branches, along the tree stem or on the roots.
• Cambial staining is evident under the bark if the affected area is cut by a knife.
• Small black fruiting bodies are also seen on the affected (dead) part of the tree.
• Botryosphaeria is a stress-related pathogen. Common stress factors include drought, severe defoliation by insects or fungi and physical damage to the tree (such as from cattle).
• As drought is a common stress factor, affected trees tend to be on ridge tops or on poorer sites.

• Throughout Queensland

Cytospora canker

• Various Corymbia and Eucalyptus species, usually only on stressed trees

Caliciopsis canker

• Spotted gum (Corymbia citriodora subspecies variegata and C. maculata)
• Dunn's white gum (E. dunnii)
• Rose gum (E. grandis) and hybrids
• Shining gum (E. nitens)
• Sydney blue gum (E. saligna)

Endothia stem canker

• Dunn's white gum (E. dunnii)
• Rose gum (E. grandis)
• Shining gum (E. nitens)
• Blackbutt (E. pilularis)
• Sydney blue gum (E. saligna)

Botryosphaeria canker

• Corymbia species
• Tallowwood (E. cloeziana)
• Dunn's white gum (E. dunnii)
• Blackbutt (E. pilularis)

Cytospora canker

• The bark at the canker site cracks and splits, but damage often only affects the outer bark.
• Often 1 tree can have multiple cankers.
• Cankers are often associated with stressed or older trees.
• They rarely cause significant damage to the tree.

Caliciopsis canker

• In severe cases, larger cankers (100–200mm long) can develop on branches and stems.
• Branches can be killed.
• Multiple severe cankers can result in tree mortality, but this is rare.

Endothia stem canker

• The cambium and sapwood under the canker eventually die. This can lead to death of the branch above the canker or of the whole tree or branch.
• Often trees recover, and the canker seals over with subsequent tree growth.
• Kino exudation from depressed cankers is often seen.

Botryosphaeria canker

• Infection commonly results in death of the affected tree part.
• Death of the tree top or whole tree can occur.

• Annual cankers – the inciting pathogen is active for 1 year only and damaged host tissue is sloughed off or overgrown.
• Perennial cankers – the pathogen is active for many years, but fungal invasion is limited by the response of the host.

• Control is not usually necessary, as trees mostly heal themselves.
• Prevent cankers by maintaining healthy trees that can fight infections.
• Avoid damage to trees, for example by cattle.
• If canker disease is diagnosed early, remove and burn individual branches or trees to help prevent spread in stressful conditions.

• Carnegie, AJ, Lawson, SA, Smith, TE, Pegg, GS, Stone, C, McDonald, JM. 2008. Healthy hardwoods: a field guide to pests, diseases and nutritional disorders in subtropical hardwoods. Forest & Wood Products Australia, Victoria.
• Old, KM, Davison, EM, 2000, Canker diseases of eucalypts. In PJ Keane, GA Kile, FD Podger, BN Brown (eds), Diseases and pathogens of eucalypts (pp 241–257), CSIRO Publishing, Collingwood, Victoria.