Welcome to CalPhytos.org – Phytophthoras in Native Habitats
Several first-in-the-USA detections and newly identified species of Phytophthora in both native plant nurseries and restoration areas have occurred in recent years. Many of these Phytophthora species appear to have wide host ranges, capable of causing disease on plants across many families and in many different habitats. The Working Group for Phytophthoras in Native Habitats has formed to determine steps needed to protect wildlands and assist the restoration industry.
More information can be found in the following:
- Background document (February 2017)
- Frequently Asked Questions (February 2017)
- Briefing paper (May 2015)
Calendar of Events
May 31, 2017 – The nursery management tour continues, this time to the South Bay/Peninsula. More details coming soon!
See the entire calendar of Phytophthora-related events.
- Guidelines to Minimize Phytophthora Pathogens in Restoration Nurseries – The Working Group for Phytophthoras in Native Habitats complied these guidelines to help design and maintain a nursery system that excludes Phytophthora and other plant pathogens to the best extent possible. These are intended for professional nursery growers that supply plants to wildland restoration projects. (Latest draft updated September 22, 2016)
- Understanding results from the CDFA lab – a handout for nurseries
- A systems approach to producing healthy container-grown plants: webinar with Dr. Jennifer Parke, Oregon State University. April 28, 2015. See all online resources and view a recording at http://uc-d.adobeconnect.com/r91g3to9726/.
- Resources from “Implementing Phytophthora Sanitation Guidelines in Restoration Nurseries: A Field Workshop,” March 1, 2017
- Guidelines to minimize Phytophthora species pathogens in restoration nurseries: rationale and review
- Nursery Case Study: Implementing the Guidelines to Minimize Phytophthora in Restoration Nurseries
- Field station photos
- Affordable Soil Heat Treating System: An example from The Watershed Nursery (video)
- Nursery Container Cleaning Instructions: An example from The Watershed Nursery (video)
- Resources from the “Managing Phytophthoras in Native Plant Nurseries: A hands-on workshop on prevention and early detection,” June 16, 2015
- Workshop agenda and speaker information
- The horticulture behind Phytophthora management
- Hands-on Irrigation Training
- Determining container physical properties worksheet
- Recognizing disease symptoms and sampling plants for the lab
- Examination & sampling for rotten roots and stems – root diagram
- CDFA Protocol for Baiting the Root Ball in a Pot for Phytophthora spp.
- CDFA Flow Through Protocol for Baiting of potted plants to detect presence of Phytophthora spp.
- Video overview of hand-on stations
These draft guidelines were developed to prevent and manage Phytophthora species during various aspects of restoration. This guidance is targeted for use in rare plant and other high-value habitats.
- “Restoration guidance” covers General Construction; Guidelines for Planting at Field Sites; Procedures for sanitizing tools, surfaces, and footwear; and Clean water specifications.
- “Contaminated site guidance” is for restoration sites that has been confirmed to contain an Phytophthora infestation.
- “Holding nursery guidance” presents a set of practices to avoid contamination of nursery stock being held for planting at restoration sites.
Phytophthora resources by species
- Concerns Over Plant Pathogen Introductions in Native Plant Nurseries and Restoration Sites. California Department of Fish & Wildlife Conservation Lecture, April 2016
- Presentations from the Do No Harm Restoration workshop, Palm Desert, November 2015
- Exotic Phytophthora Species in Native Plant Nurseries, Restoration Plantings, and Wildlands, video recording. Courtesy of the Central California Native Plant Nursery Network, December 2, 2014
- Plant pathogen movement: around the world on planting stock – Susan Frankel, USDA-Forest Service, Pacific Southwest Research Station (http://youtu.be/KZAlexLWNGY)
- Phytophthora species: life cycle, distribution, dispersal, impacts in California – Ted Swiecki, Phytosphere Research (http://youtu.be/lMw4NpDgCTs)
- P. tentaculata: History, Host Range, and Status in California Nurseries – Suzanne Rooney Latham, CDFA (http://youtu.be/HK4-NMsDbm8)
- Best Management Practices to minimize the risk of Phytophthora and other pests and pathogen introductions into nurseries – Kathy Kosta, CDFA (http://youtu.be/oKEQqDBU3vw)
- Systems approach to Phytophthoras in nurseries – Karen Suslow, NORS-DUC (http://youtu.be/CuPYc9lcCcc)
- Phytophthora Effects on Native Habitat Restoration – Greg Lyman, SF Public Utilities Commission (http://youtu.be/ypRe4nX6fSo)
- Case Study: Incorporating CDFA BMPs at a restoration nursery – Diana Benner, The Watershed Nursery (http://youtu.be/7AEnZp2-_14)
Phytophthora tentaculata was initially detected in a native plant nursery causing a severe root and crown rot in sticky monkey flower, Diplacus aurantiacus subsp. aurantiacus (Scrophulariaceae) in 2012. Since then it has been detected in several nurseries and a few restoration sites where outplanted stock was found to be infected.
- CDFA Plant host list for Phytophthora tentaculata, February 2016
- USDA Phytophthora tentaculata Pest Alert, February 2015
- CDFA Nursery Advisory No. 01-2014 Phytophthora tentaculata, November 2014
- 2010 APHIS New Pest Response Guidelines, “Phytophthora species in the Environment and Nursery Settings.” Includes Phytophthora tentaculata literature review and pictures of the pathogen in culture.
Rooney-Latham, Suzanne; Cheryl Blomquist; Ted Swiecki; Elizabeth Bernhardt. 2015. Phytophthora tentaculata. Forest Phytophthoras 5(1). doi10.5399/osu/fp.5.1.3727. A compendium of information on Phytophthora tentaculata that includes photographs of field symptoms, a table of known hosts and more, geared to a technical audience and containing many photomicrographs. (PDF for download) http://journals.library.oregonstate.edu/index.php/ForestPhytophthora/article/view/3760/3652
Rooney-Latham, S., C. L. Blomquist, T. Swiecki, E. Bernhardt, and S. J. Frankel. 2015. First detection in the US: new plant pathogen, Phytophthora tentaculata, in native plant nurseries and restoration sites in California. Native Plants Journal 16:(1) 23-27. Abstract: Phytophthora tentaculata Kröber & Marwitz (Pythiaceae) has been detected in several native plant nurseries in 4 California counties and in restoration sites on orange sticky monkey flower (Diplacus aurantiacus (W. Curtis) Jeps. subsp. aurantiacus [Scrophulariaceae]), toyon (Heteromeles arbutifolia (Lindl.) M. Roem. [Rosaceae]), coffeeberry (Frangula californica (Eschsch.) A. Gray [Rhamnaceae]), and sage (Salvia spp. L. [Lamiaceae]). These findings are the first detections of P. tentaculata in the US and the first ever on these host plants. Phytophthora species are a known problem in horticultural nurseries, but little attention has been placed on native plant or restoration nurseries. The potential for plant pathogens to be outplanted along with native plant nursery stock is very high, posing a threat to neighboring forests. http://npj.uwpress.org/content/16/1/23.abstract.
- Mission Statement (draft as of November 2015)
- Working Group Organizational Chart (draft as of January 2016)
Contact Janice Alexander for more details on how you can be involved with the Working Group.