Wednesday, July 8, 2009

Fishing for Phytophthora

Murdoch University in Western Australia officially launched a "Fishing for Phytophthora" website on 6/5 at the Dieback Information Group meeting. The website is intended to catalogue Phytophthora species found in Western Australia's rivers, streams, dams, and estuaries. Currently over 100 locations are being monitored. Website information includes a project overview, a detailed map with findings noted at each location, an interpretation of the findings, the latest news on the project, and a photo gallery. To access the website, go to: http://www.fishingforphytophthora.murdoch.edu.au/. For more information on the project, contact Daniel Hüberli at D.Huberli@murdoch.edu.au.

And if you are interested in a similar program being developed in Washington, check out our website:
http://www.puyallup.wsu.edu/ppo/sod/monitoring/stream%20monitoring.htm

New research suggests that snails and slugs may transmit P. ramorum spores

Hyder, N.; Coffey, M.D.; and Stanghellini, M.E. 2009. Viability of oomycete propagules following ingestion and excretion by fungus gnats, shore flies, and snails. Plant Disease 93:720-726.

Abstract: Sporangia of Phytophthora capsici and P. nicotianae, as well as hyphal swellings of Pythium splendens, P. sylvaticum, and P. ultimum, were ingested by adult shore flies but none were viable after passing through the digestive tract. Oospores of Pythium aphanidermatum retained their viability following ingestion by adult shore flies. Larval stages of fungus gnats and shore flies ingested sporangia of Phytophthora capsici, P. nicotianae, and P. ramorum, but they were not viable upon excretion. In contrast, hyphal swellings of Pythium
splendens, P. sylvaticum, and P. ultimum, chlamydospores of Phytophthora ramorum, and oospores of Pythium aphanidermatum, retained their viability after passage through the digestive tract of these larvae. Snails were capable of ingesting and excreting viable sporangia and chlamydospores of P. ramorum, which upon excretion infected detached leaves. Although the impact of larvae and snails in the rapid dissemination of pathogen propagules is unknown, this work does highlight the possibility that some often-ignored animal–fungus interactions should be considered in long-range dispersal of pathogen propagules via food webs.

New P. ramorum finds in Washington

A Kitsap County, WA residential landscape site was found to have
P. ramorum-positive Rhododendron Sp. 'Roseum Elegans' on 6/10/09 as part of a trace-forward investigation from an infested wholesale/production nursery in Thurston County, WA. The plant was removed and destroyed per the APHIS, PPQ "Official Regulatory Protocol for Phytophthora ramorum Detections in Landscaped Residential or Commercial Settings."

A King County, WA production nursery was confirmed to have
P. ramorum-positive Rhododendron Sp. 'Jean de Montaque' and Rhododendron Sp. 'Wojnar's Purple' on 6/23/09. The nursery was also found positive in 2006, 2007, and 2008.

From the July COMTF newsletter
http://www.suddenoakdeath.org/html/current_newsletter.html