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Abstract
Phytophthora ramorum was identified as the cause of a leaf blight on rhododendrons in an historic garden in Cornwall in 2003. A programme of measures was set in place to eradicate the disease from the garden and several sites were selected to monitor the effect of these measures on the recovery of
P. ramorum from soil, leaf litter, rainwater and watercourses. The results from two monitoring sites are presented plus the results of leaf baiting of the watercourses. After the removal of the infected rhododendron at Site 1 and the application of a composted mulch over the soil surface,
P. ramorum was no longer detected in the soil samples. At another site (Site 4), which consisted of a clump of several large ?Cornish Red? rhododendrons, removal of the host was not practical, and instead, the lower branches were removed to encourage airflow through the canopy. Although the detection of
P. ramorum in soil samples has radually declined at this site, fallen leaves have continued to harbour the pathogen, with some seasonal variation showing lowest recovery during the summer months. Recovery of
P. ramorum from watercourses was also lowest in the summer and greatest in the spring.
Parent Publication
Citation
Lockley, David; Turner,Judith; Humphries, Gillian; Jennings, Phil. 2008. Monitoring
Phytophthora ramorum in soil, leaf litter, rain traps, and watercourses in an historical cornish garden. In: Frankel, Susan J.; Kliejunas, John T.; Palmieri, Katharine M., tech. coords. 2008. Proceedings of the sudden oak death third science symposium. Gen. Tech. Rep. PSW-GTR-214. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. pp. 393-395
