Phytophthora ramorum

Phytophthora ramorum is an exotic fungus-like plant pathogen which causes damage to trees, shrubs and other plants. Since the mid 1990's, it has caused widespread death of millions of trees in forest environments in coastal California and Oregon in the USA. Because the most commonly affected trees that have been killed are tanoaks (not true oaks) as well as several true oak species, this extensive phenomenon is commonly known as 'Sudden Oak Death' in the USA. The pathogen was first found in the nursery trade in the USA/Canada in 2001.

In Europe, including the UK, P. ramorum has been found mainly on container-grown Rhododendron, Viburnum and Camellia plants in nurseries. It was first detected in the UK in 2002. Following the first finding emergency measures were introduced in Great Britain. The initial measures included destruction of infected plants, a ban on imports of susceptible material from affected areas of the USA, and notification of movements of susceptible nursery stock i.e. rhododendron (other than R. simsii), and viburnum. These measures were notified to the EU Standing Committee on Plant Health, which agreed EU-wide emergency measures in November 2002, based largely on GB's action. Those measures are still in place.

In January 2009 the first finding in the wild of Phytophthora ramorum on Bilberry, Vaccinium myrtillus, was confirmed at a site in Staffordshire

Since the first confirmations in 2002 there has been a coordinated approach to disease control within GB aimed at containment and eradication whilst evidence was gathered to make a decision on future policy. During that time the disease has continued to spread, albeit slowly and mainly in the southern and western parts of GB. Following a review of the historic and current situation, available scientific and economic evidence and public consultation on options for management of the pathogen in the future, Ministers concluded that more needs to be done to contain and eradicate P. ramorum and another fungus-like pathogen, Phytophthora kernoviae.

A new 5 year programme, which began on 1 April 2009, includes research and development, an awareness programme and disease control through funding clearance of host plants in high risk areas. This will involve an increased level of activity, aimed at reducing the level of inoculum to epidemiologically insignificant levels; by removal of infected sporulating hosts in woodlands and the wider environment and proactive clearance of uninfected areas to protect high risk sites; combined with enhanced containment and eradication measures in infected gardens and nursery sites, as well as the identification and control of any new outbreaks.