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Water Willow Mark Disease

Symptoms

Water mark disease symptoms can be seen in mid to late spring. The leaves will turn reddish and wither, thus the affected areas of the tree will slowly deteriorate and die.

Cycle of infection

This disease seems to take effect in mid to late spring and is transferred by birds, insects and air currents to open tree wounds. This disease is not found in many places of the country and not every willow is infected.

Implications for host

When the disease forces its way into the wood producing toxins which cause leaf discolouration, the leaves turn red. The tree will start to ooze bacteria and the affected area on the tree will die back. This disease will rarely kill the tree but plays about with the trees growth and vigour. When the wood is dissected, watermarks are stained internally on infected cut surfaces that show partial red or black rings.

Treatments

Though this disease does not necessarily kill the tree, it is a hazard to others. The infected areas of the tree should be removed, but even then there is a risk of reinfection. If the damage is bad enough, the whole tree should be removed and burnt. The same applies if you are just removing branches.

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