Canker

When canker or fruit tree cancer is, unlike the name suggests, not cancer ( uncontrolled growth of cells), but a fungal infection of bark and wood.

Pathogen

When canker are fungi of the genus Pustelpilze. For fruit trees (apple, pear) this is the type Nectria galligena. Other species of the genus Nectria infect beech, ash or rowan.

Infection

Infection commonly occurs via the tree wounds in the bark or the wood, for example at cuts, or cracks in the bark, such as those caused by frost. Especially great is the risk of infection in wet weather, in autumn, when the trees shed the leaves fall and this gives rise to the branches leaf scars, or in winter when the wood rests.

Disease

The infested by the fungus beef areas are colored orange or brown and are dry and cracked. In the fall, then form it globose reddish spore. In young shoots or on newly planted trees, the destruction caused by the fungus can often throughout the shoot or stem cover, which means that it dies. Thicker branches can often live for years with infection, without dying. In some varieties to the affected area then forms a collar which is thicker from year to year. Because of this, such as tumors looking collar this disease also received the name " cancer ". Except for infection of shoots may be caused by Nectria galligena also a fruit rot at the core of fruit.

Prevention and control

When choosing the variety should be taken to plant less susceptible varieties. In apple trees Privy Dr. Oldenburg, Braeburn, Gloster, Rubinette, Elstar, clear apple and Berlepsch are the varieties Cox's Orange Pippin, James Grieve, Jonagold, McIntosh, Summerred, Ingrid -Marie, Goldparmäne, very vulnerable.

To be avoided is excessive supply of nitrogen.

If a tree is infected, so there are several ways of fighting. Firstly, cutting out the infected wood parts to the healthy wood and the destruction of the removed wood parts, including disinfection of the tools. Secondly, you can shield existing sores and prevent further spread by spraying with certain substances already.

Canker on a birch

Canker on a butternut

Apple tree with cancer

Canker on a Cherry Tree