P.ramorum

By
May 8, 2007, 11:38

Sudden oak death positive environmental sample
During April, APHIS confirmed the presence of P. ramorum in a stream-bait sample taken from the Sammamish Slough near Bothell.  The sample was taken by DNR as a part of its routine environmental monitoring and analyzed at the WSDA lab.  A stream-bait sample consists of rhododendron leaves from a susceptible variety taken from a known non-infected site.  The leaves are encased in a mesh bag and suspended in flowing water at the sample site for approximately two weeks.  To date, none of DNR's other samples have shown positives.
 
Since the discovery, WSDA has been actively gathering more stream-baits out throughout the watershed.  We are attempting to verify whether the sample result is repeatable in subsequent samples, to begin to trace the limits of any infestation that exists, and to start tracing the source of any infestation.  The source might be as simple as fallen leaves from an infested nursery, or it might be a landscape infestation. 

If there is evidence of a landscape infestation, or if WSDA cannot trace the source of repeated positives, either federal or state quarantine of a portion or all of King and/or Snohomish Counties might occur.  The size and particulars of such a quarantine would depend on the situation. 

There are approximately 100 nurseries in the Sammamish watershed, and we are giving serious attention any possible sources, but there is no way of knowing at this time.

At this time, WSDA does not yet have enough information to make any predictions.