Phytophthora ramorum and Phytophthora kernoviae are exotic plant pathogens that have been identified in UK recently: P. ramorum in 2002, and P. kernoviae in 2003. It is not a name that rolls off the tongue easily and for those struggling with pronunciation try – ‘fy-toff-thora’!
Both species represent a threat to ornamental and wild shrubs, and trees, but of more interest to the Trust is that Bilberry Vaccinium myrtillus has been found the be severely infected by both pathogens. Other heathland species and their wider ecosystsems may also be under threat.
A Defra-funded Phytophthora spp Disease Management Programme has been approved, beginning on 1st April 2009 with funding of £25m over 5 years. The programme will address the problem through three workstreams: disease management, awareness and behavioural change, and research.
In England and Wales, there have been over 250 outbreaks of P. ramorum or P. kernoviae outside of nurseries of which about a quarter have been eradicated so far. In May 2009, outbreaks in Scotland were reported to be 29 largely centred around the west coast heritage gardens and nurseries from Portpatrick to Poolewe, but there have been 25 outbreaks in other areas.
The principal leaf host is Rhododendron R. ponticum which appears to drive epidemics. Research to date has shown that the eradication of rhododendron is the single most effective control measure to reduce pathogen and disease spread in the wider environment (woodland, heathland, gardens and parks) and protect vulnerable trees and heathland plants.
For more information and photographs see the guidance available on the Defra website.
Defra appears to have adopted a sensible approach to the Phytophthora problem, but in this season of heightened awareness about heather beetle, the effort being put in place to combat Phytophthora spp serves to highlight the apparent complacency about the damage that heather beetle can cause to moorland and heathland. Am I missing something?