Nursery updates

Thirty-three nurseries in eight states (CA, OR, WA, NC, ME, NY, PA. and IN) had P. ramorum confirmations in 2012 (up from 23 nurseries in 5 states in 2011), including 17 interstate shippers (16 in regulated states and 1 in NY) and 16 non-interstate shippers.  Sixteen of the finds (48.5%) were first time detections (CA-3, OR-7, WA-2, NY-1, IN-1) and 17 (51.5%) were repeat nurseries.  Although host plants from P. ramorum-positive nurseries were shipped to 33 states, when trace-forward investigations were conducted, positive plants were detected in only 2 non-interstate shipping nurseries (ME, PA) and four residential (ME, CA, OR, WA) locations.  Of the four positive residential finds, two (ME, CA) were traced back to a nursery in OR and two (OR, WA) were traced back to a WA nursery.

High-risk host plants comprised 85% of confirmations: Rhododendron (OR-16, WA-14, CA-7, NY-7, ME-5, PA-1, IN-1), Camellia (CA-5, OR-4, WA-1, NC-1), Viburnum (OR-7, WA-2, CA-1), Pieris (OR-4, WA-2, NY-1), and Kalmia (OR-2, NY-1).  The remaining 15% of confirmations came from:  Cornus kousa (OR-1), Gaultheria procumbens-a newly identified host-(WA-1, ME-1, OR-1), Gaultheria shallon (OR-1), Hamamelis intermedia (OR-1), Hamamelis virginiana (OR-1), Loropetalum chinense (CA-3), Magnolia grandiflora (OR-2, WA-1), Prunus laurocerasus (OR-1), Trachelospermum jasminoides (CA-1), cull pile material(OR-1), potting media(OR-3), soil substrate (OR-4, CA-2, ME-2, WA-1), and water (WA-6, NY-2).

California Nursery-Related Summary, 2012 – California had seven P. ramorum-positive nurseries in 2012, of which four were previously positive.  Five confirmations came from production facilities and two were retail.  Two of the nurseries were in the quarantine area and five were in the regulated area.  Of the 18,235 samples tested, there were 17 positive plant samples (6- Camellia, 6-Rhododendron, 1-Viburnum, 3- Loropetalum, 1- Trachelospermum).

Oregon Nursery-Related Summary, 2012 – Oregon tested 21,353 samples for P. ramorum from 542 grower sites as part of the Federal P. ramorum Certification Program in 2012. The pathogen was detected at 11 nurseries on Camellia, Hamamelis virginiana, Kalmia latifolia, Pieris, Rhododendron, and Viburnum. Delimitation surveys within the positive nurseries detected additional infections on Camellia, Cornus kousa, H. intermedia, Magnolia grandiflora, Pieris, Prunus laurocerasus, Rhododendron, and Viburnum, as well as in potting media, soil, and a cull pile. All of the nurseries underwent the USDA Confirmed Nursery Protocol. P. ramorum was also detected at a residential site on Gaultheria shallon and G. procumbens plants imported from a P. ramorum-positive nursery in Washington. This was the first time Gaultheria procumbens had ever been found positive for the pathogen. The USDA Confirmed Residential Protocol was enacted and completed at the site.

From the February COMTF Newsletter.