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Washington State University
WSU Puyallup Ornamental Plant Pathology

Evaluation of fungicides for use against P. ramorum

The Forest Service, Washington State Pesticide Commission, Pacific Northwest Christmas Tree Association, IR-4 program, and the WSDA Nursery Research Program are supporting research at WSU Puyallup to determine the effectiveness of various fungicides in protecting conifers and rhododendrons from infection by this pathogen. This work has shown that several traditional contact materials, such as mancozeb, and the systemic material Subdue MAXX, have the potential to provide excellent control of diseases caused by P. ramorum. However, growers and regulatory agencies are concerned that the use of fungicides may be masking symptom development, thus making it harder to prevent the spread of this pathogen on infected nursery stock. Additional studies will be conducted at the National Ornamentals Research Site at Dominican University, California (NORS-DUC) to determine the residual effectiveness of fungicides and determine if any of them have the potential to mask symptom development on infected plants.

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Publications

Effectiveness of fungicides in protecting conifers and rhododendrons from Phytophthora ramorum 220 KB
Gary A. Chastagner, Annie DeBauw, Kathy Riley, and Norm Dart

Cristi Palmer and Ely Vea. 2006. IR-4 Ornamental Horticulture Program Phytophthora Efficacy.

Chastagner, G.A., E.M. Hansen, K.L. Riley, and W. Sutton. 2005. Effectiveness of fungicides in protecting Douglas-fir shoots from infection by Phytophthora ramorum. Sudden Oak Death Science Symposium II, 18-21 January 2005, Monterey, CA.

Chastagner, G.A., E.M. Hansen, K.L. Riley, and W. Sutton. 2004. Effectiveness of fungicides in protecting Douglas-fir shoots from infection by Phytophthora ramorum. Phytopathology 94: S16.

Chastagner, G.A., E.M. Hansen. 2003. Identification of fungicides to control sudden oak death. Christmas Tree Lookout 36(3): 7-9.

Chastagner, G.A., E.M. Hansen, K.L. Riley, and W. Sutton. 2003. Identification of fungicides to control sudden oak death. In: Program and abstract book, sixth international Christmas tree research and extension conference; 2003 Sept. 14-19; Hendersonville, NC; 36.

Contact: Gary Chastagner, 253-445-4528 | WSU Puyallup Research & Extension Center, 2606 West Pioneer, Puyallup, WA, 98371-4998 USA
Last updated January 2, 2013