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Plant disease found in Scotland
10/01/2008
A fungus-like pathogen which attacks shrubs, particularly Rhododendron, and trees, has been found in Argyll.
Phytophthora kernoviae was first found in the south-west of England in 2003, and is mainly found in Cornwall and south Wales.
However, the first finding in Scotland has now been made on two Rhododendron plants in a private garden.
The Scottish Government, together with the Forestry Commission, will be taking forward action to survey the location and its surroundings, ensure the infected plants are destroyed and prevent the disease spreading.
Guidance material for gardeners on how to minimise the risk of introducing Phytophthora ramorum and Phytophthora kernoviae is available on the Scottish Government and Forestry Commission websites.
Phytophthora kernoviae acts in a similar way to Phytophthora ramorum, which has now been found in four gardens in Scotland.
It causes damage to shrubs and trees, particularly Rhododendron and Beech, and may also affect heathland plants. It is mainly found in Cornwall and south Wales, in woodland, parks and gardens. Symptoms and control measures are similar to those of Phytophthora ramorum.
The pathogen causes bleeding bark cankers on certain tree hosts, especially in the family Fagaceae (e.g. Beech and Oak); these cankers can girdle and kill affected trees. It also causes leaf blights or dieback on a range of shrub hosts and also some trees; these foliar hosts are responsible for producing inoculum which can infect the stems of susceptible trees. The known hosts of Phytophthora kernoviae to date include Fagus sylvatica (Beech), Rhododendron spp., Quercus robur (English oak), Quercus ilex (Holm Oak), Gevuina avellana (Chilean Hazelnut), Liriodendron tulipfera (Tulip Tree), Magnolia stellata, Michelia doltsopa and Pieris formosa. In England, trees with bleeding bark cankers have to date all been in close proximity to infected rhododendron, particularly Rhododendron ponticum.
An interdepartmental Programme Board, with representatives from Defra, the Forestry Commission, the Scottish Government, Welsh Assembly Government and Northern Ireland Government oversee a programme aimed at containing both P. ramorum and P. kernoviae.
When infected plants are found they are required to be destroyed, together with any host plants within 2m. Inspectors will survey the rest of the site, taking samples as necessary, and will continue to monitor it over coming months. Movement and sale of plants will be restricted as appropriate. RPID will monitor the garden and, together with Forestry Commission staff, will carry out surveillance in a 3km wide zone around the outbreak site.
The Scottish Government is in the process of carrying out its annual survey for Phytophthora kernoviae and Phytophthora ramorum in established gardens and landscaped sites throughout Scotland. Over 50 sites will be inspected. Inspectors will also visit gardens where the owners raise concerns about relevant plants, and those within 3km of any positive finding. All samples taken are tested for both pathogens.