Novel Phytophthora and biodiversity impacts
Phytophthora is a genus of plant-damaging water moulds
that are responsible for a number of notorious plant diseases, such
as potato blight. Three species, named ramorum,
kernoviae and pseudosyringae have recently been
identified in the UK affecting heathland plants. They are
believed to be non-native, and may have been introduced via
international horticultural trade.
Phytophthora ramorum and kernoviae can affect
a wide range of native and garden plants. Until recently,
‘wild’ findings were restricted to infections of the non-native
invasive species Rhododendron ponticum, however it has now
spread to infect native bilberry. Laboratory testing shows
that other native species such as heather, cowberry and bearberry
may also be highly susceptible.
Once infections occur, they can spread very rapidly through
other susceptible species, as infected bilberry or
Rhododendron produce very high numbers of spores.
Some spores also remain in the soil and can infect germinating
plants. Trees are also affected by Phytophthora
ramorum or kernoviae, and they can be killed by the
infection. However, most infected trees do not produce
spores, and will normally only become infected if they are in close
contact with other infected plant species.