New webinar

A new webinar from the irrigation pathogens group on "Substrate management practices vital for pathogen risk mitigation" will be posted soon on their website. Check out the website below for this and other webinars:

http://www.irrigation-pathogens.ppws.vt.edu/webinar/index.php

Integrated management of zoosporic pathogens and irrigation water quality for a sustainable green industry is sponsored through the Specialty Crop Research Initiative (SCRI) of USDA-National Institute of Food and Agriculture (NIFA). Award #2010-51181-21140.

Webinar - Alternative disinfectant water treatments for nurseries

Title: Alternative disinfectant water treatments
Date: Tuesday, April 8, 2014
Time: Noon to 1:00 pm (Eastern)
Presenter: Dr. Warren Copes, USDA-ARS Southern Horticultural Lab in Poplarville, MS
To participate in this webinar, please go to https://connect.extension.iastate.edu/irrigation-water/
and dial 1-888-619-1583 then enter pass code: 491981

Stream monitoring for P. ramorum in WA, 2013 results

Washington Department of Natural Resources Phytophthora ramorum update – Phytophthora ramorum waterway monitoring as well as forest and nursery perimeter surveys have been conducted in Washington since 2003, with efforts since 2006 focusing on aquatic areas near previously positive nurseries.  In 2013, 11 P. ramorum stream baiting sites were established in western Washington waterways, of which two were identified as positive – one in Clallam County and one in Thurston County.  Eleven additional sites were repeatedly sampled in Clallam County as the source of the inoculum there is unknown; however, results to date have been negative or inconclusive.
In 2013, the water monitoring sampling methodology was changed from stream baiting with mesh bags to the Bottle-of-Bait method in the interest of increasing efficiency.  Since waterway sampling began in 2005, P. ramorum has been detected in seven waterways in western Washington:  two in King County and one each in Clallam, Clark, Lewis, Pierce, and Thurston Counties.  Diseased plants were found associated with one of the waterways in 2010 (Pierce County) and were destroyed.

Stream monitoring updates

Three new positive waterways were identified in Georgia, Texas, and Washington in 2012 as a result of the National P. ramorum Early Detection Survey of Forests, bringing the total number of known positive sites outside of the established disease range in CA and OR to 15.  Seventeen states participated in the program, for a total of 114 stream baiting locations in all.  Of the 12 previously positive sites in AL, FL, GA, MS, NC, and WA, 11 were surveyed in 2012 and continue to be positive, reinforcing the trend of annual repeat detections once a site is initially confirmed.

The newly identified Texas stream was baited in response to positive soil findings at an associated nursery in the summer of 2012; however, no P. ramorum-positive plants were identified.  The last time the nursery had confirmed positive plants was in 2004 as a result of the nationwide P. ramorum-positive Camellia shipment.  Water baiting in the stream outside of that nursery was also conducted in 2010 and found negative.
Washington’s 2012 P. ramorum early detection survey of forests resulted in four positive water confirmations.  One of the sites was a new P. ramorum-positive location: a watershed sub-basin adjoining the Sammamish River, King County (which has been P. ramorum positive since 2007).  Three other locations were repeat positives for P. ramorum: one in a stream that feeds into the Sammamish River, one in the Sammamish River, and one in a Lewis County stream in a forested area.  None of the finds were in association with streamside plant infections.  In total, there were 12 baiting traps in 11 western Washington streams in 2012.  All baited streams were associated with nurseries previously identified with P. ramorum-positive plant stock.

The 2011 survey of water baiting methods (comparing in vitro baiting, Bottle O’Bait, and in situ baiting, bags) was expanded in 2012 and yielded consistent results with those obtained in 2011.  Sampling occurred at 25 positive sites in 6 states.  The pathogen was recovered by one or both assays in 139 comparable cases.  In vitro baiting was the more effective method overall (55 percent of recoveries); however, after analysis with 2011 data, it was clear the advantage was seasonally based, with spring being optimal.  The rate of P. ramorum recovery overall was lower in the fall, at which time in situ baiting was a more reliable method.  The pathogen was recovered by in vitro assay at nine sites over the two survey years when in situ baiting failed.  Without in vitro baiting, these sites would have been classified P. ramorum negative.  However, there was one site in 2012 where in situ succeeded and BOB failed.  Based on survey results, 2013 National P. ramorum Early Detection Survey of Forests cooperators will have the option of using either assay.  Unfortunately, due to budget shortfalls, it is anticipated that the 2013 program will be greatly reduced.

From the February COMTF newsletter.

Water treatment research at WSU

The Chastagner lab at Washington State University, Puyallup plans to develop a biofiltration testing facility and determine the effectiveness of several techniques for removing P. ramorum inoculum from water. Methods similar to those being used for remediating stormwater are being considered for removing pathogen inoculum from nursery runoff and will have the added advantage of removing pollutants. These methods will consist of biofilters using various organic substrates, constructed wetlands or rain gardens, and physical methods such as sand filtration or sedimentation. Pilot biofiltration systems will be installed at selected P. ramorum-positive nurseries in Washington and be part of a training program for nursery managers. A Best Management Practices workshop will also be held for nursery managers regarding the installation and maintenance of cost-effective biofiltration systems for removal of Phytophthora inoculum in water. Funding for the project has been made possible by the Farm Bill and the Washington State Department of Agriculture Nursery Research Program.

From Sept. 2012 COMTF newsletter

Questions? Comments? Email Marianne Elliott

Webinar - Scheduling Lawn and Garden Watering on your Smartphone or Web Browser

Learn how to plan your watering to eliminate flooding and Phytophthora problems. Attend this free webinar:

“Scheduling Lawn and Garden Watering on your Smartphone or Web Browser”

When do I turn the water on?  How long do I leave it on?  These are simple questions with difficult answers.  This webinar will describe how to use a new irrigation scheduling tool that runs equally well on a Smartphone or any web browser to greatly simplify making these decisions in a way that will result in green lawns and healthy gardens, save you work, and most importantly save on your water bill!

Tuesday May 29^th at 7:00 PM go to breeze.wsu.edu/rain and log in as a guest. Dr. Troy Peters, WSU Extension Irrigation Specialist will guide viewers  through the process and answer questions.

Washington stream monitoring updates

The Washington State Department of Agriculture will no longer be monitoring waterways in the state as of 2012. Nursery-level monitoring required under the Confirmed Nursery Protocol will continue. Stream baiting efforts are still be conducted by the Washington Department of Natural Resources (DNR); however, with 2012 sampling having commenced in late January in 5 counties and 10 watercourses. The first (of likely six) round of samples has been retrieved for analysis. In addition to leaf baiting, DNR will be working with the USDA Forest Service on “Bottle of Bait” protocols to assay each of the streams for P. ramorum. More baiting stations will likely be added to the survey over the course of the sampling period if P. ramorum is detected at any of the sites.

from the March COMTF newsletter

P. ramorum in water workshop now on the web

Preventing the spread of Phytophthora ramorum via water was the focus of a 2 ½ day workshop in Puyallup, WA, June 28-30, 2011. Attended by over 50 regulators, researchers, and industry representatives from the western and southeastern US, as well as Washington, DC, the workshop's mission was to coalesce research, management, and regulations for effective, economical, and environmentally acceptable ways of limiting P. ramorum spread via contaminated nursery water runoff. The group began the meeting with a visit to the site of a previously positive Gig Harbor retail nursery (where P. ramorum-infested water had escaped the nursery and infected riparian salal plants) to review treatments and mitigations implemented. Meeting presentations addressed the incidence and distribution of P. ramorum detections in waterways, water baiting techniques, risks and impacts for WA, and treatments to reduce the risk of spreading inoculum in water. Research and education/outreach needs were identified, with group exercises and discussion concentrated on nursery treatments as well as water management, monitoring, and notification of downstream users of contaminated water. More information on the workshop can be found at: http://www.puyallup.wsu.edu/ppo/sod/extension/workshops/Pr_water_jun_2011/index.html. The meeting was organized by Gary Chastagner, Washington State University, and Susan Frankel, USDA-Forest Service, Pacific Southwest Research Station, and sponsored by Washington State University and the California Oak Mortality Task Force.

New water finds of P. ramorum in Washington

Washington had two new and one repeat P. ramorum-positive waterway detections in June. One of the new positives was detected upstream from a 2010 positive site. The positive stream feeds into the Sammamish River. The other new positive was detected in a watershed sub-basin adjoining the Sammamish River. The repeat detection site has been positive since 2010 and is in a stream that feeds into the Sammamish. While the exact source of the inoculum remains unknown, genetic evidence points toward previously positive nurseries in the associated watershed.

From the July COMTF newsletter

'Super sand' to help clean up dirty drinking water

And Phytophthora-infested water?

Contaminated water can be cleaned much more effectively using a novel, cheap material, say researchers.

Dubbed "super sand", it could become a low-cost way to purify water in the developing world.

The technology involves coating grains of sand in an oxide of a widely available material called graphite - commonly used as lead in pencils.

Read the rest of the article on BBC News

Slow Sand Filtration Project

Slow Sand Filtration Project for South Carolina P. ramorum-Positive Nursery – The Clemson University Department of Plant Industry strives to protect SC's agricultural resources and natural ecosystems from the introduction and spread of invasive species such as P. ramorum. One nursery in SC has had positive detections of P. ramorum for three consecutive years. While surveys indicate that eradication efforts have eliminated P. ramorum from nursery stock, the pathogen continues to be found in the nursery's water and soil; however, perimeter forest surveys and stream baiting of the river associated with this nursery have all been negative to date.

In an effort to maintain the pathogen-free status of the natural area outside of the nursery, Clemson University researchers and the nursery owner are installing a slow sand filtration system in which all runoff will be directed into a vegetated ditch that will lead to a small retention pond for sediment dispersal. The water from the pond will be pumped into a slow sand filtration system and then drain to another vegetated area for diffusion before entering the river. Each component of the system will be monitored by Clemson University researchers. The nursery and river will continue to be tested for P. ramorum according to USDA CNP protocol and the state compliance agreement. For more information, email Christel Harden.

From the June COMTF Report

P. ramorum in Washington waterways

Washington had two repeat P. ramorum-positive waterway detections in May. One of the sites has been positive since 2009 and the other since 2010. Each positive stream feeds into the Sammamish River. Both sites have had positive samples recovered upstream from the confluence of the water course and the Sammamish (baiting by WSDA and WA DNR); the inoculum source for each is unknown.

from the June COMTF report

WSU monitoring on Clarks Creek

A link to a page on WSU stream monitoring for Phytophthora on Clarks Creek, Puyallup, WA:

http://www.cityofpuyallup.org/services/development-services/puyallups-stormwater-management-program/clarks-creek-initiative/current-restoration-efforts/

Phytophthora species in streams

Hwang, J.; Jeffers, S.N.; and Oak, S.W. 2010. Aquatic habitats—A reservoir for population diversity in the genus Phytophthora. Phytopathology 100:S150.

Occurrences of oak decline and sudden oak death in forests of Europe and the west coast of the U.S.A., respectively, have focused attention on the species of Phytophthora present in natural ecosystems. We have been investigating the diversity of species of Phytophthora present in forest streams in the eastern U.S.A. Phytophthora spp. are well adapted to aquatic environments and can be recovered from stream water by baiting and filtration. Extensive surveys in multiple states revealed that a diversity of species occurs naturally in forest streams. In one study, five forest streams in western North Carolina were monitored monthly for a year. Seven species—P. cambivora, P. cinnamomi, P. citricola, P. citrophthora, P. gonapodyides, P. heveae, and P. pseudosyringae—and seven morphologically and genetically distinct groups of isolates were detected. Samples of stream-side soils and plants with symptoms also were collected, but only three species were detected: P. cinnamomi and P. heveae in soils and P. citricola and P. heveae on plants. Species of Phytophthora consistently were detected in streams during winter months when air temperatures were near or below freezing, which are not conducive to lesion development and sporulation. These results suggest that the native population of Phytophthora spp. in stream water is different from those in terrestrial habitats. The species of Phytophthora present in streams may occupy a unique niche—i.e., they appear to be aquatic inhabitants and not transient visitors.

Stream in NC positive for P. ramorum

Water draining an infested nursery in Mecklenburg County (Charlotte), NC has been found to have Phytophthora ramorum as a result of the 2010 National P. ramorum Early Detection Survey of Forests. The rhododendron leaf baits were deployed by survey cooperators in the NC Forest Service and diagnosis made from several baiting periods via PCR by the survey's Eastern Regional Diagnostic Lab at the Pennsylvania Department of Agriculture. This brings the total number of positive waterways to 10 in six states outside areas where P. ramorum is found in California and Oregon forest areas (WA [2], AL [4], MS [1], GA [1], FL [1], and NC [1]). Cooperative streamside vegetation surveys are being planned for the fall by the USDA Forest Service, NC Forest Service, and NC Department of Agriculture and Consumer Services to determine if the pathogen has become established in terrestrial ecosystems.

from COMTF July newsletter

How pathogens can survive in aquatic environments

This article may give some insights into how P. ramorum can persist in a stream environment:

Islands of Germs: Researchers Discover Pathogens Floating on Tiny Clumps of Aquatic Detritus

Researchers have found evidence that "marine snow"--aggregates of organic material floating in water bodies--may act as microscopic, island-like refuges for pathogens, or disease-causing organisms. This detritus may skew water sampling procedures and mathematical models used to predict the transmission of waterborne diseases to humans.

(follow the link above to read the whole article)

WSU stream monitoring program

The Washington State University, Puyallup (WSU-P) SOD community-based stream monitoring program was piloted in March 2010 in Washington's Puget Sound region. In addition to increasing the number of streams monitored for P. ramorum throughout the state by the Washington State Department of Agriculture (WSDA) and Washington Department of Natural Resources (WADNR), the new program also has potential to increase community awareness about the spread of P. ramorum and other Phytophthoras in streams. WSU-P received two years worth of funding from the USDA Forest Service to manage this program, which involves Master Gardeners, high school and college students, and other volunteers. Baiting sites were chosen based on discussions with WSDA and WADNR, and also volunteer availability. In 2010 four sites are being monitored for six two-week intervals and three sites for one two-week interval. The two-week interval sites are part of class projects for UW-Tacoma and Pierce College. Some students are also doing projects in the lab related to disinfectant use and survival in saline conditions. The program will be expanded in 2011. No P. ramorum has been detected at any of the sites so far. For more information, go to http://www.puyallup.wsu.edu/ppo/sod/monitoring/stream%20monitoring.htm or contact Marianne Elliott at melliott2@wsu.edu.

From the May COMTF newsletter

Assessing the potential of Silv-Exﾮ and Silv-Ex Plusﾮ to eradicate Phytophthora ramorum spores in water

Assessing the potential of Silv-Exﾮ and Silv-Ex Plusﾮ to eradicate Phytophthora ramorum spores in water - Based on two studies at UC Davis, using Silv-Ex® or Silv-Ex Plus® (foaming agent used in fire control) to treat water that is potentially infested with P. ramorum, greatly reduces, but does not eliminate, the concern for inadvertently spreading the pathogen through fire suppression efforts. For more information, contact Kamyar Aram at kamaram@ucdavis.edu.