Sudden Oak Death — Abstract of Paper


Phytophthora ramorum and Sudden Oak Death in California: IV. Preliminary Studies on Chemical Control
Matteo Garbelotto,¹ David M. Rizzo,² and Lawrence Marais³


Chemical applications may provide one means of control for Phytophthora ramorum, the cause of Sudden Oak Death (SOD). Such controls have been effective with other Phytophthora species in landscape and orchard situations. We have initiated laboratory and field studies to test the efficacy of a number of products previously reported to control Phytophthora. "In vitro" tests have determined that many of the standard chemical controls (e.g., metalaxyl, copper sulfate, phosphoric acid) are effective against P. ramorum. Field and green house studies include experiments to treat trees and saplings already infected with the pathogen as well as treatments to protect trees from infection. Application of chemicals has been by drench, injection, and topical application directly to the bark. Although preliminary results are positive, it should be pointed out that use of chemical controls will be limited to urban situations and specimen trees. It is unlikely that chemical controls will be of practical use in California wildland situations.