Trace Forward and Perimeter Surveys for Sudden Oak Death in Texas.

D. N. Appel, Dept. of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, (979) 845-8273, appel@ag.tamu.edu; T. Kurdyla, Dept. of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843; R.F. Billings, K.S. Camilli and A. Purdy, Texas Forest Service, 301 Tarrow, College Station, TX 77840

Four sponsored nursery surveys for sudden oak death (SOD) have been or are currently being conducted in Texas. This poster concerns the Trace Forward (spring 2004) and Perimeter Surveys (fall 2004), each of which have focused on 112 nurseries receiving plant materials from Monrovia Nursery in California. A total of 1620 samples were collected from the Trace Forward nurseries, consisting of 6 genera and 15 species of plants. There were 50 positive PARP isolations, of which 33 were Phytophthora ramorum, the SOD pathogen. These specimens were taken from 5 nurseries. Another 5 nurseries have been confirmed for SOD through TAMU Texas Plant Diagnostic Laboratory. ELISA had a 55% success rate in correctly identifying PARP positive samples for P. ramorum. Alternatively, ELISA had a 3% false positive rate. One hundred and thirteen samples have been collected in the Perimeter survey. There are 32 species, of which seventeen were oaks (Quercus spp.). No Phytophthora spp. has been isolated from these specimens, nor have any of the replicate samples tested positive for P. ramorum with PCR. Nursery operators, landscape maintenance personnel, natural resource managers and homeowners have benefited from these surveys by a better understanding of the SOD threat in Texas.

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