The quick links below will take you to more detailed information and documents for download.

Best Management Practices for Nurseries

Guidelines for Restoration and Fieldwork

Sampling and Diagnostic Guide for Soil-borne Phytophthora species on California Native Plants Part 1. Selecting Plants to Sample

Resources from workshops, meetings, and mailings

Resources by species: P. tentaculata and others

General pathology resources

Resources for regulators

Best Management Practices for Nurseries

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Guidelines for Restoration and Fieldwork

These draft guidelines and best management practices (BMPs) aim to prevent and manage Phytophthora species during restoration activities and other field work, including trailwork and construction projects. This guidance is targeted for use in rare plant and other high-value habitats but may be applied to all areas where sustaining natural resources is a priority.

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Resources from workshops, meetings & mailings

If you’ve attended one of our events, or just want to see what was covered, see below for more details and links to resources. Events are listed in reverse chronological order. Also included are updates sent to our mailing list.

November 2023 vitrual CalPhytos meeting

June 2022 CalPhytos update

Native Plant Buy-in Seminar. November 15, 2021 – Recording & Follow up Q&A

COMTF Virtual Annual Meeting, Day 3: CalPhytos meeting with presentations concerning Phytophthoras in restoration and natural areas (2 hrs). September 23, 2021 – Recording

Healthy Plants Forever After: the online meeting of the Phytophthoras in Native Habitats Work Group. June 30, 2020 – Recording

Tour of Sanitation Practices at Restoration Nurseries – Placerville. Placerville and Camino, CA; April 19, 2018 – Agenda

Joint meeting of the CNPS Ad-Hoc Committee and the Phytophthora Work Group. Los Angeles, CA. February 3, 2018 – Meeting summary

Tour of Sanitation Practices at Restoration Nurseries – San Francisco. San Francisco, CA; January 26, 2018 – Photos

Tour of Sanitation Practices at Restoration Nurseries – South Bay/Peninsula. Palo Alto, CA; May 31, 2017 – Photos and Pot-washing station video

Phytophthora Species in Restoration Nurseries, Plantings, and Wildlands II. San Jose, CA; May 18, 2017

Implementing Phytophthora Sanitation Guidelines in Restoration Nurseries: A Field Workshop. Richmond, CA; March 1, 2017

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

Managing Phytophthoras in Native Plant Nurseries: A hands-on workshop on prevention and early detection. Albany, CA; June 16, 2015

A systems approach to producing healthy container-grown plants: webinar with Dr. Jennifer Parke, Oregon State University. April 28, 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 (
  • Phytophthora species: life cycle, distribution, dispersal, impacts in California – Ted Swiecki, Phytosphere Research (
  • P. tentaculata: History, Host Range, and Status in California Nurseries – Suzanne Rooney Latham, CDFA (
  • Best Management Practices to minimize the risk of Phytophthora and other pests and pathogen introductions into nurseries – Kathy Kosta, CDFA (
  • Systems approach to Phytophthoras in nurseries – Karen Suslow, NORS-DUC (
  • Phytophthora Effects on Native Habitat Restoration – Greg Lyman, SF Public Utilities Commission (
  • Case Study: Incorporating CDFA BMPs at a restoration nursery – Diana Benner, The Watershed Nursery (

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Phytophthora resources by species

Phytophthora tentaculata

Phytophthora tentaculata was initially detected in a native plant nursery causing a severe root and crown rot in sticky monkey flower, Diplacus aurantiacuss ubsp. 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.

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

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.

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General Pathology Resources

Threats to oaks and other native plants from root-rotting Phytophthora species (handout by Dr. Tedmund J. Sweicki for the University of California Oak Health Virtual Workshop, April 2020)

Reid, A. (2006), Sampling and testing for plant pathogens. Department of Agriculture and Food, Western Australia, Perth. Bulletin 4683.

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Resources for Regulators

Sample text from Santa Clara Valley Water District for General Project Conditions for Phytophthora and Phytophthoras and Nursery Stock. Posted January 2023.

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