Northern Olympic Peninsula, WA Phytophthora ramorum stream monitoring will be expanded in spring 2015 in an effort to identify the source of inoculum contaminating the Dungeness River near Sequim, WA. The river was found positive twice in 2013 and is not in the vicinity of a P. ramorum-positive nursery. To date, follow-up sampling of streams in the area have not yielded information about the inoculum source. The Chastagner lab at Washington State University, Puyallup will oversee the additional monitoring through a volunteer program and increase efforts to genotype isolates and DNA samples from waterways to help clarify the inoculum origin. Several stormwater retention ponds in Pierce County will also be monitored to determine if landscaped areas in new developments may harbor the pathogen.
2014 National P. ramorum Early Detection Survey of Forests Summary – Along the West Coast, California, Oregon, and Washington conducted stream surveys using bottle of bait (BOB) and/or leaf baiting. In CA, 146 sites were sampled over 5 baiting periods, with 19 positive samples collected (13 from previously positive locations). Six of the positives were from watersheds that had not previously tested positive (See the January COMTF report for more information.). In OR, 11 sites were sampled over 19 baiting periods, resulting in the detection of 6 positive waterways. The OR survey samples were tested via culturing and PCR, with PCR diagnostics identifying 10 samples that were not found through culturing. In WA, both BOB and leaf mesh bag sampling were used. The two positive samples found were with the bait bag sampling method (not BOB) and from the same stream.
Four of the 9 participating eastern states had 9 P. ramorum-positive stream samples – AL (4), FL (1), MS (2), and NC (2). Two of the positive streams (AL-1; FL-1) have not been previously positive and are each associated with a positive nursery. Another Alabama positive stream has not been previously positive but is not associated with a positive nursery. Plans for vegetation sampling near this stream are underway.
Bottle of bait (BOB – whole leaves and leaf pieces together in a bottle of collected water) monitoring protocols were adopted to detect P. ramorum for the forest stream survey in 2014. BOB whole leaves detected five positive streams and leaf pieces detected four. Nine environmental plant samples from Georgia were tested for P. ramorum, but all were negative. As found in previous years (2010-2013), the spring (March – May) bait period resulted in more positive samples (7) than the late season (October – November; 2). In total, 665 BOB samples were processed from 85 different sites in 9 eastern states (AL, FL, GA, MS, NC, NY, PA, SC, and TX).
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