Surveying for Phytophthora ramorum in ornamental nurseries, home landscapes, and forests in Georgia, USA.

Jean L. Williams-Woodward, Department of Plant Pathology, University of Georgia, Athens, GA 30602

Six ornamental production nurseries in Georgia were surveyed for Phytophthora ramorum in 2003. No P. ramorum was detected in 946 plant samples (508 nursery and 438 nursery perimeter/forest). Other Phytophthora species, mostly P. cinnamomi and P. parasitica, were recovered from Rhododendron and Pieris leaves from 50 nursery and 2 perimeter samples.

Trace forward surveys in 2004 identified 14 retail nurseries that received P. ramorum-infected camellia plants from Monrovia Nurseries, Azusa, CA. Adjacent plants, as well as the forested nursery perimeters were surveyed and no P. ramorum was detected. From January 2003 to March 2004, Georgia received 28,000 plants from Monrovia Nurseries in Azusa. A collaborative effort to recover purchased suspect P. ramorum-infected plants was initiated by the Georgia Department of Agriculture, Georgia Forestry Commission, and The University of Georgia Cooperative Extension Service. Three camellia samples were confirmed positive out of 221 home landscape samples. All known infected plants were removed and no P. ramorum was detected in a survey of landscape plants, soils, or forested environ away from the infected plant. P. ramorum was introduced into Georgia, however, there is no evidence that P. ramorum has spread or become established within retail nurseries,

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