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 What
is Sudden Oak Death?
Sudden
Oak Death is the common name for a disease caused by Phytophthora
ramorum, a previously unknown and exotic plant pathogen.
- P.
ramorum is currently only known to occur in 14 counties in
California, a small area in southwestern Oregon and several European
countries.
- P.
ramorum has killed hundreds of thousands of oak and tanoak
trees in
 California.
This
pathogen can infect a large number of plants, including Douglas-fir,
grandfir, rhododendron, viburnum, big leaf maple, vine maple, madrone,
Pacific yew, salal, and other tree, shrub, and herbaceous plant
species in Washington's natural and urban landscapes.
- P.
ramorum spreads aerially through forest landscapes by wind
and wind-driven rain.
-
P. ramorum survives in infested plant material, litter,
soil, and water and can be moved long distances in nursery stock.
Does
Sudden Oak Death Pose a Threat to Washington?
Western
Washington is a "high risk" area for diseases caused by
P. ramorum because of favorable environmental conditions
and the abundance of susceptible host plants.
P.
ramorum has been detected in 33 western Washington nursery sites
since the summer of 2003, but eradication efforts appear to have
prevented its spread to plants in Washington's forest and urban
landscapes. The recent detection of P. ramorum in a stream
associated with an infested nursery illustrates the potential for
this organism to spread from nurseries into Washington's natural
and urban landscape.
While
the ecological impacts of P. ramorum in Washington are unknown,
the spread of this pathogen to plants in our forest or urban landscapes
would trigger a series of quarantines for Washington's horticulture
and forestry products. The destruction of infected plant material
in nurseries to eradicate P. ramorum and prevent its further
spread has already caused millions of dollars in losses to the nursery
industry in California, Washington, and Oregon.
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