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An invasive pathogen causing bleeding cankers on beech tree trunks, necrosis on leaves of rhododendrons, pieris and magnolias, and extensive dieback of bilberry.
The novel species Phytophthora kernoviae was first isolated from beech and rhododendron by scientists from Forest Research and the Food and Environment Research Agency (now Fera Science) in 2003. Its likely origins are in the Southern Hemisphere, because it has been found in New Zealand and Chile.
Our research into this highly aggressive pathogen shows it attacks leaves, buds and shoots of under-storey rhododendron in woodlands, as well as ornamental garden plant species. Woodland trees such as beech can also be at risk of infection if they are growing within a few metres of affected rhododendron because of the number of spores released from infected foliage of this shrub.
This resource provides information from our research about the distribution and spread of this infection. Our guide to symptoms will help you to identify infected rhododendrons so you can take precautionary action to destroy these plants.
These can also be general symptoms caused by some other plant pathogens, including the more widespread Phytophthora ramorum in rhododendron. Please consult our symptoms and diagnosis page for help and advice on identifying P. kernoviae infections in plants and trees. A fact sheet is also available from FERA.
Our Tree Health Diagnostic and Advisory Service offers laboratory-based infection diagnosis. Phytophthora screening provides an accurate diagnosis to support your management decisions and obligations.
There is no cure for P. kernoviae infection. Therefore to prevent or limit the spread of disease, owners and managers should consider removing and destroying all infected plants, following the management procedures advised for P. ramorum.
Our scientists first isolated, identified and characterised Phytophthora kernoviae as a new species in 2003. Our research, funded by Defra and the Forestry Commission’s Phytophthora Programme, investigated the organism's method of spread, the process of infection, and disease management strategies.
Our work covers or has covered:
Our research has led to the following publications:
We are among the leading research institutes looking into Phytophthora organisms and the diseases they cause, including Phytophthora austrocedri on juniper, Phytophthora on alder, Phytophthora lateralis and Phytophthora ramorum, the cause of ramorum disease, sometimes known as sudden larch death when it occurs on larch trees (species in the Larix genus).