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Pests and Diseases that affect Trees

Host Specific Pests and Diseases

The range of tree species which are able to thrive in the urban environment is quite limited. Pollution, development, pests and diseases, underground services, cables and purely being situated close to human activities work together to produce harsh conditions very different to woodlands. Those tree species which do grow well are often related, as they share the characteristics which enable them to tolerate these harsh conditions. For example, many small ornamental species such as Rowan, Thorn and Cherry are all members of the Rosaceae family. Consequently, it is often found that a pest or disease that can affect one species, is also able to affect related species. Therefore, in order to stop the spread of a disease or pest, which would seriously deplete the tree stock of the Borough, it may be necessary to carry out sanitation felling of susceptible trees to contain an outbreak.

 

Non-Specific Pests and Diseases

There are many pests and diseases, which are not found specifically on one type of tree or family of trees and do not always spread rapidly to other trees. However, they may cause local loss of trees or damage to trees.

 

Council Policies

The Council will carry out the pruning or felling of Council owned trees, when appropriate, to help prevent the spread of pests or diseases through an individual tree or group of trees or to make safe a tree which has become dangerous because of pests or diseases.

  • Justification: The devastation caused by Dutch Elm Disease is well known and there are other pests and diseases which are specific to other tree species more commonly found in towns. If an outbreak of disease or pest were to occur unchecked, due to the limited variety of species grown in towns, the losses would be significant. Alternatively, there are many pests and diseases, which do not lead swiftly to tree death. Over several years, however, they may affect the trunk and branches or base and roots to a point at which the tree becomes dangerous. The safety of the public is the priority at all times.

  • Implementation: Work will be carried out as necessary to halt the spread of pests and diseases where practicable, to prevent a tree becoming unsafe, or to fell a tree which has been decayed to a point beyond which its safe retention is doubtful. The Council will continue to notify the relevant authorities of outbreaks of notifiable diseases or pests and take such action as is recommended or instructed by these authorities. Pruning or preventative spraying will be carried out in preference to felling, if practicable. When necessary the Council will inform members of the public of the symptoms or characteristics of a pest or disease in order to help tree owners safeguard the health of all trees within the Borough.

 

The Council will carry out any pruning or felling work necessary to Council owned trees to contain outbreaks of Brown Tailed Moth (Euproctis chrysorrhoea) caterpillar.

  • Justification: The protective hairs of the Brown Tailed Moth caterpillar are an irritant if touched and therefore in the interests of public health, any infestations will be dealt with as a priority.

  • Implementation Pruning, felling or spraying of infested trees will be carried out as a priority matter by staff trained in the safe disposal of such material. When necessary public information material will be supplied to help safely contain an outbreak of the moth.

 

The Council will resist the felling of trees solely as a result of aphid secretion (Honeydew) problems.

  • Justification: Honeydew is the natural sticky secretion from aphids, which in summer feed on the sap of trees, particularly Lime and Sycamore. In some circumstances, this residue may cause problems by sticking to the surfaces on which it falls. However, as it may be removed by washing and is a seasonal problem, trees will not be removed solely for this reason.

  • Implementation: In exceptional circumstances pruning work may be carried out to remove branches where this does not have a detrimental effect on the tree. Future planting of trees in sensitive locations will not include those species which are particularly vulnerable to aphid attack.

 

For further information, please contact us using the details below.

Contact Details

  • Name Green Care
  • Address Directorate of the Urban Environment, Lister Road Depot, Lister Road, Dudley, west Midlands, DY2 8JW
  • Telephone 0300 555 2345