Update on tree infections by Phytophthora ramorum in United Kingdom
As reported in EPPO RS 2003/145 and 2003/162, several trees infected by Phytophthora ramorum (EPPO Alert List) were found in United Kingdom, in the vicinity of diseased Rhododendron. As of February 2004, 9 trees at 3 sites in Cornwall have now been found infected by P. ramorum. These trees are: 4 Quercus ilex (European holm oak), 1 Q. cerris (Turkey oak), 2 Fagus sylvatica (beech), 1 Castanea sativa (sweet chestnut) and 1 Aesculus hippocastanum (horse chestnut). On C. sativa and Q. ilex, symptoms were only seen on leaves, but on F. sylvatica, Q. cerris and A. hippocastanum, conspicuous bleeding cankers were observed. In Europe, two other trees (American oak species) are known to be infected: a Q. falcata (Southern red oak) in Sussex and a Q. rubra (Northern red oak) in a park in the Netherlands. At one of the sites in Cornwall, another species of Phytophthora, which has not yet been identified, was detected causing a disease on rhododendrons and a nearby beech tree. Investigations on the identity of the pathogen and the risk it may present are being carried out. It is recalled that at the majority of the 300 reported outbreaks in United Kingdom (mainly confined to rhododendrons in nurseries and garden centres), eradication has been achieved by the immediate destruction of the plants. Eradication and containment measures will continue, and surveillance will be increased to reduce the risk of spread of P. ramorum into the wider natural environment.
NPPO of United Kingdom, 2004-02.
Forestry Commission and DEFRA News Release of 2004-02-01. ramorum disease: update. http://www.defra.gov.uk/news/2004/040202b.htm