02117nas a2200193 4500008004100000022001400041245009800055210006900153260001600222300001400238490000800252520150500260100002201765700001601787700002201803700001801825700001501843856006501858 2016 eng d a0191-291700aDetection of Phytophthora ramorum in Nurseries and Forest Lands in California in 2004 to 20090 aDetection of Phytophthora ramorum in Nurseries and Forest Lands  cJan-01-2016 a139 - 1480 v1003 a

From December 2004 through May 2009, samples were collected from California nurseries and wild lands to survey for Phytophthora ramorum and comply with federal regulations of nursery stock. Samples were prescreened by an enzyme-linked immunosorbent assay (ELISA) that detects Phytophthora spp. and tested by culture, P. ramorum-specific real-time polymerase chain reaction (PCR), and nested PCR. Yearly percentages of infected samples ranged from 0.6 to 2.3%. Camellia spp., Rhododendron spp., Magnolia spp., Pieris spp., and Laurus nobilis tested positive the most frequently in the nurseries and Lithocarpus densiflorus, Umbellularia californica, and Quercus agrifolia tested positive most often from wild lands. Of the 118,410 samples isolated onto PARP media, 0.8% was identified as P. ramorum. Of 115,056 samples tested by ELISA, 5.9% tested positive for Phytophthora spp. Of the 6,520 samples tested by PCR, 12.4% tested positive for P. ramorum. The false-negative, positive, and internal control failure rates of the assays are discussed. After removing the seasonal effect of sampling strategy, isolation of the pathogen into culture was found to be seasonally dependent whereas detectability by PCR and ELISA was not. To our knowledge, this is the first evaluation of a regulatory testing program for a plant pathogen on this scale using standardized assays.

1 aBlomquist, C., L.1 aYakabe, L E1 aRooney-Latham, S.1 aMcRoberts, N.1 aThomas, C. uhttp://apsjournals.apsnet.org/doi/10.1094/PDIS-12-14-1302-RE