Situation of Phytophthora kernoviae in the United Kingdom
Since the first discovery of Phytophthora kernoviae (EPPO Alert List) in Cornwall in 2003 (EPPO RS 2005/165) intensive surveys have been carried out in the United Kingdom. Between October 2003 and December 2008, P. kernoviae was found at 69 sites in England and Wales, mainly affecting rhododendron (Rhododendron ponticum and other rhododendron hybrids) in small areas of woodland in Cornwall. The pathogen has also been detected on a number of trees species. In addition to Cornwall, P. kernoviae has been found once in Devon, and in 6 locations in South Wales and 1 location in north-west England (on a single mature rhododendron plant – now eradicated). In nurseries, only 3 findings have been made: 2 in Cornwall (still under official control) and 1 in Cheshire which was subsequently eradicated. In January 2008, P. kernoviae was detected for the first time in Scotland on 2 established rhododendron plants (10 to 15 years old) in a private garden in Argyll (west of Scotland). In February 2008, 2 rhododendrons and 1 Drimys winteri plant in a garden were found infected by P. kernoviae on the Isle of Arran (west coast of Scotland). So far, P. kernoviae has not been detected in Northern Ireland.
In the United Kingdom, rhododendrons are probably the most commonly affected plants but P. kernoviae has been found on many other species belonging to the families Aquifoliaceae, Araliaceae, Ericaceae, Fagaceae, Magnoliaceae, Podocarpaceae, Proteaceae, Rosaceae and Winteraceae. Symptoms include bleeding cankers on trees of Fagus sylvatica (beech), Quercus robur (oak) and Liriodendron tulipifera (tulip tree), foliar blights and shoot dieback on trees and ornamentals as well as bud blast on Magnolia. Symptoms have been observed on stems of Hedera helix (ivy), and leaves of Drimys winteri, Gevuina avellana, Ilex aquifolium, and Podocarpus salignus. Leaf and stem symptoms have been seen on Prunus lauroceraus and Vaccinium myrtillus (blueberry). Concerning blueberries, mildly symptomatic plants were sampled from a mixed broad-leaved woodland in a valley in Cornwall and Kochs postulates were completed in 2008, confirming that V. myrtillus is host plant of P. kernoviae.
The situation of Phytophthora kernoviae in the United Kingdom can be described as follows: Present, England and Wales (mainly found in Cornwall) and Scotland, under official control.
Sources
INTERNET (last retrieved in 2009-03)
DEFRA
Revised Summary Pest Risk Analysis for Phytophthora kernoviae (2008). http://www.defra.gov.uk/planth/pra/pker.pdf
Phytophthora kernoviae outbreaks in England and Wales (2008-12-11). http://www.defra.gov.uk/planth/pkernovii2.htm