The conker tree is an old favourite, although not indigenous, arriving from the Balkans in the 1500’s it supports a lot of native wild life as well as providing hours of fun in the playground – however in some circles safety goggles must be donned! This aside, many of them are looking distinctly poorly this year. At first it was thought that they were suffering from a root rot but now it has transpired that they have ‘bleeding canker’ or Pseudomonas syringae pv aesculi ! The disease manifests by sap oozing lesions in the bark or ‘bleeding cankers’ on both the trunk and branches. If these cankers manage to girdle the tree then it will die. Infected trees can sometimes recover as they form calluses around the wounds, however many die in 3 – 5 years.
In 2007 The Forestry Commission undertook a survey to assess how widely trees are affected and results showed that up to 49% of trees were showing some degree of symptoms. The disease has been around since the 1970’s however it was thought then that the trees were suffering from root rot and it is only now, that scientist realise that it was probably ‘bleeding canker’. The last few wet summers and mild winters seem to have increased the instances of ‘bleeding canker’. Trees of all ages can be affected by the recent disease upsurge and even young trees with a stem diameter of only 10cm have been found with advanced symptoms. There is no chemical treatment available not that it would be practical to apply it if there was one. If a tree needs to be felled affected branches and trunks should be destroyed and not left around as they might act as reservoirs for infection of other trees. Either burning or burying is probably the best method of disposal. It is recommended that logs cut from the wood are not kept hanging around for firewood but disposed of as soon as possible. Chipping the stump and felled wood is not recommended as it may lead to spreading the disease. In Holland, however, they compost the chippings at a high temperature 60 degrees centigrade in a controlled environment.