Phytophthora: oft-proposed candidate pathogen

There are more than 100 species in this genus, whose name translates as "plant destroyer".    

P. ramorum is responsible for sudden oak death; P. infestus caused the Irish Potato Famine.  Lisa Cieko discovered a 1984 report:

Root Rot of Western Swordfern Caused by Phytophthora cinnamomi in California The California conservation community is actively  monitoring and attempting to remedy extensive outbreaks of Phytophthora species which primarily come from nursery stock, described here: Bay Nature:  New Strains Breaking the Mold From the California Forest Pest Council: We have not been able to verify the presence of Phytophthora at Seward Park.   Seward Park Audubon's Kathryn Sechrist asked a San Francisco State botanist colleague to comment on our videos, and received this response: As to the fern die-off ... I looked over the blog. Although not confirmed, it sure sounds like Phytophthora. It has become a huge problem here in CA, particularly with native plant propagation. I was just at a CNPS board meeting where a policy was passed to try to deal with protocols for raising natives. Huge burden on propagators! Really too bad. But, serious implications for natural systems as well."