First report of Phytophthora pseudosyringae on Vaccinium myrtillus in the United Kingdom
The NPPO of the United Kingdom recently informed the EPPO Secretariat of the first finding of Phytophthora pseudosyringae on bilberry plants (Vaccinium myrtillus). In January 2008, V. myrtillus plants in woodlands of Staffordshire (West Midlands region) were observed with symptoms of stem dieback and some were already dead. In May 2009, similar symptoms were also found on V. mytillus in a woodland located in the south-west of England. It was suspected initially that the plants were infected with P. ramorum or P. kernoviae (both on the EPPO Alert List), however, testing has confirmed that V. myrtillus plants were infected with P. pseudosyringae. This is the first time that P. pseudosyringae is reported on V. myrtillus.
P. pseudosyringae was first isolated and described in 2003 from forest soils around oak trees (Quercus petraea, Q. robus, Q. cerris) in Europe. It was also isolated from necrotic roots and bark at the stem base of European beech (Fagus sylvatica) and from necrotic bark and rhizosphere soils of Alnus glutinosa (see EPPO RS 2005/162). In the USA, P. pseudosyringae was isolated from Umbellularia californica (most common host), Quercus agrifolia, Lithocarpus densiflorus in California and Oregon, as well as in stream waters in North Carolina. Isolated findings have been made in California on the foliage of Acer macrophyllum and Arctostaphylos sp. In 2006, P. pseudosyringae was detected in Spain (in Galicia) on chestnut (Castanea sativa) nursery stock. In 2007, the UK Forest Research reported findings of P. pseudosyringae on two mature trees of Fagus sylvatica and one mature hornbeam (Carpinus betulus) in south Wales. Sampled in 2005, these trees exhibited symptoms including bleeding cankers and root lesions. The trees were originally suspected to be infected with P. ramorum. These were the first records of P. pseudosyringae in the UK and the first record on C. betulus. In 2009, Forest Research identified P. pseudosyringae as the cause of bleeding cankers on Nothofagus procera in Cornwall, another new tree host.
The currently known distribution of P. pseudosyringae is as follows:
EPPO region: Italy, France, Germany, Spain, United Kingdom.
North America: USA (California, Oregon). Found in stream waters in North Carolina.
Sources
NPPO of the United Kingdom, 2009-06.
Beales PA, Giltrap PM, Webb KM, Ozolina A (2009) A further threat to UK heathland bilberry (Vaccinium myrtillus) by Phytophthora pseudosyringae. New Disease Reports volume 19 (February to August 2009). http://www.bspp.org.uk/publications/new-disease-reports/ndr.php?id=019056
Denman S, Rose J, Slippers B (2007) Phytophthora pseudosyringae on European beech and hornbeam in the UK. Poster presented at the 4th IUFRO Working Party Meeting ‘Phytophthoras in forest and natural ecosystems, Monterey, US, 2007-08-26/31. http://nature.berkeley.edu/IUFRO2007/phytophthora/tnp/denman_poster.pdf
Hwang JS, Oak SW, Jeffers SN (2008) Detecting Phytophthora ramorum and other species of Phytophthora in streams in natural ecosystems using baiting and filtration methods. General Technical Report - Pacific Southwest Research Station, USDA Forest Service, 55-58.
Pintos Varela C, Mansilla Vazquez JP, Aguin Casal O, Rial Martinez C (2007) First report of Phytophthora pseudosyringae on chestnut nursery stock in Spain. Plant Disease 91(11), p 1517.
Reeser PW, Sutton W, Hansen EM (2008) Phytophthora species causing tanoak stem cankers in southwestern Oregon. Plant Disease 92(8), p 1252.
Wickland AC, Jensen CE, Rizzo DM (2008) Geographic distribution and pathogenicity of Phytophthora nemorosa and Phytophthora pseudosyringae in California, USA. Forest Pathology 38(4), 228-298.