OAK trees are facing devastation after a deadly fungal disease was discovered in Dorset.

It has led to a ban on imports of plants from parts of the USA.

The Government said added controls would be imposed to protect native trees and shrubs from the new disease.

Phytophthora ramorum, a fungus which causes a rapid wilting disease known as 'sudden oak death', is killing native oak trees and other plants in California and Oregon. Once diseased, plants can die within a few months.

It has been discovered at nurseries in Dorset, which have not yet been named by government officials.

It is not known whether or to what extent the disease might affect trees and plants here, and Phytophthora ramorum is not established in this country.

The affected plants found in Dorset and a small number of other nurseries in the country were destroyed and possible sources of infection are being investigated to determine whether there has been any spread.

In order to reduce further risk of the disease spreading to and within the UK, ministers have announced a ban on the import of rhododendron, viburnum, vaccinium and oak planting material from areas of the USA where the disease is known to occur.

Imports of oak wood from North America are already subject to measures such as removal of bark to reduce other risks.

The Government has urged the European Commission to require Member States to carry out surveys of potential host material this summer and to report their findings later this year.

The Commission has now agreed to draft measures for consideration at the next meeting of its plant health committee.

The fungus has been found infecting rhododendrons and viburnums in the Netherlands and Germany.

However, preliminary Forestry Commission research suggests that European species of oak may be more resistant to the fungus than North American species.

DEFRA and the Forestry Commission are undertaking further research.