Tedmund J. Swiecki and Elizabeth A. Bernhardt are plant pathologists and principals of Phytosphere Research, 1027 Davis Street, Vacaville, CA 95687. This work was developed with support from USDA Forest Service, State and Private Forestry, Forest Health Protection Agreement No. 08-DG-11052021-144 with additional support provided by the Pacific Southwest Research Station.
Opinions expressed may not necessarily reflect the position of the U.S. Department of Agriculture.
The use of trade or firm names in this publication is for reader information and does not imply endorsement by the U.S. Department of Agriculture of any product or service.
Support for this publication was provided by the USDA Forest Service, State and Private Forestry, Forest Health Protection, Midpeninsula Regional Open Space District, the San Francisco Public Utilities Commission, and the USDA Forest Service, Pacific Southwest Research Station. The authors wish to thank the following for review and guidance; Everett Hansen, Oregon State University; Phil Cannon, USDA Forest Service, Pacific Southwest Region, Forest Health Protection; Chris Lee, University of California Cooperative Extension, Humboldt and Del Norte Counties; Ellen Natesan, San Francisco Public Utilities Commission; Cindy Roessler, Midpeninsula Regional Open Space District; and Susan Frankel, USDA Forest Service, Pacific Southwest Research Station.
All photos and drawings are by the authors except where indicated otherwise.