World Phytophthora Collection at the University of California, Riverside

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Introduction and History 

The World Phytophthora Collection (WPC) contains about 2000 isolates of over 160 species, collected from multiple plant hosts or aquatic environments around the world. Most isolates are Phytophthora, although a few other genera including Pythium are also represented. 

The collection was founded by former department faculty D. C. Erwin and G. A. Zentmyer. Isolates from the collection have been used in several hundred scientific publications by researchers around the world studying topics such as plant pathology and evolution. The collection is currently co-curated by James Adaskaveg and Howard Judelson.

Obtaining isolates
Phytophthora 2

Isolates are currently maintained in liquid nitrogen, which allows for long-term storage. Click here to view the list of available isolates in the collection: 

Phytophthora Inventory List

To request an isolate, please submit your contact information, shipping address, permit*, and a list of the isolate(s) being requested (using the "P" numbers, i.e. P1306) to the appropriate order form below:

New Customer Order Form      Returning Customer Order Form

Our charges are $350 (USD) per culture, or $295 for 10 or more isolates. Packaging and express shipping charges are extra (about $100 (USD) for domestic addresses, or about $200 (USD) for international shipments). We will contact you regarding billing information.

*A permit to transport isolates must be in place before isolates can be shipped out. To avoid delays in processing, please upload a PDF copy of your permit to the order form. Information on permits: For shipping within California (CDFA); For shipping within the United States (USDA-APHIS); For shipping internationally, please consult country's specific regulations for importing isolates and provide required documentation.


The survival of the collection is entirely dependent on charges for cultures and donations. If you would like to donate to the Phytophthora Collection Fund, please visit our Giving page.

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