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Loose Leaf: The official blog of American Forests

January 23, 2015 gary.maguire

Loose Leaf is a great blog on tree pests and what can be done to strengthen forests.

Potential for P. ramorum infection of conifer hosts

January 21, 2015 gary.maguire

Potential for P. ramorum infection of conifer hosts

In spring of 2004, WSU initiated a research project to examine factors influencing P. ramorum infection in Christmas tree plantations with funding provided by a two-year USDA Forest Service grant. Work on this project is occurring at the Black Road Christmas Tree Farm near Los Gatos, CA. This is a 23-acre U-cut Christmas tree farm that was established in 1966. Conifers being grown at this site include Douglas-fir, grand fir, giant sequoia, scotch pine, white fir, and California red fir. Some known P. ramorum hosts in the forest adjacent to the edge of the farm include:

California bay laurel, madrone, big leaf maple, toyon, coast redwood, and tanoak. Dieback on some of the grand and Douglas-fir along the interface between the infected forest and the Christmas tree farm appears to have occurred at least 4 years previously, in 2000. During 2005, conditions were very favorable for disease development. Results from this study indicate that most of the infected Christmas trees occurred within 2 meters of the edge of the P. ramorum-infected bay laurel forest canopy. Virtually no infection was evident on Christmas trees that were >5 meters away from the forest edge.

Given recent developments in the UK, where P. ramorum is infecting conifers, further research at WSU-P is being done on the susceptibility of conifer species in western Washington forests.

Publications

Susceptibility of Larch, Hemlock, Sitka Spruce, and Douglas-fir to Phytophthora ramorum

Gary Chastagner, Kathy Riley, and Marianne Elliott
In Frankel, S.J.; Kliejunas, J.T.; Palmieri, K.M.; Alexander, J.M. tech. coords. 2013. Proceedings of the Sudden Oak Death Fifth Science Symposium. Gen. Tech. Rep. PSW-GTR-243. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 169 p.

Symptoms Associated with Inoculation of Stems on Living Douglas-fir and Grand Fir Trees with Phytophthora ramorum 15 KB
Gary Chastagner, Kathy Riley, Katie Coats, Marianne Elliott, Annie DeBauw, and Norm Dart.
In Frankel, Susan J.; Kliejunas, John T.; Palmieri, Katharine M. 2010. Proceedings of the Sudden Oak Death Fourth Science Symposium. Gen. Tech. Rep. PSW-GTR-229. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 378 p.

Chastagner, G.A., E.M. Hansen, K.L. Riley, and W. Sutton. 2005. Susceptibility of conifer shoots to infection by Phytophthora ramorum. Sudden Oak Death Science Symposium II, 18-21 January 2005, Monterey, CA.

Chastagner, G.A., K.L. Riley, E.M. Hansen, and W. Sutton. 2004. Christmas tree and conifer nursery stock: Sudden oak death project update. Christmas Tree Lookout 37(3): 10-13.

Chastagner, G.A., E.M. Hansen, K.L. Riley, and W. Sutton. 2004. Susceptibility of conifer shoots to infection by Phytophthora ramorum. Phytopathology 94: S16.

Chastagner, G.A., E.M. Hansen, K.L. Riley, and W. Sutton. 2003. Susceptibility of conifer shoots to infection by Phytophthora ramorum. In: Program and abstract book, sixth international Christmas tree research and extension conference; 2003 Sept. 14-19; Hendersonville, NC; 10-11.

Contact: Gary Chastagner, 253-445-4528 | WSU Puyallup Research & Extension Center, 2606 West Pioneer, Puyallup, WA, 98371-4998 USA
Last updated January 2, 2013

Biological control of tanoak and bay laurel resprouts using indigenous decay and sap-rotting fungi

January 21, 2015 gary.maguire

Biological control of tanoak and bay laurel resprouts using indigenous decay and sap-rotting fungi

In southwest Oregon, an aggressive program of cutting and burning host plants in an effort to eradicate Phytophthora ramorum was begun in 2001. It was soon apparent that tanoak (Lithocarpus densiflorus) resprouts were highly susceptible to P. ramorum and that infected sprouts hamper eradication efforts by maintaining inoculum on site.
The basidiomycete fungus Chondrostereum purpureum causes a white rot of mostly broadleaf trees and has a wide host range. It invades through fresh wounds in the xylem or cut stumps and is a weak pathogen that can survive as a saprophyte. After the host tree is weakened or killed, C. purpureum is quickly replaced by other, more competitive decay fungi that are naturally occurring in the environment. This fungus is used as a biological control agent for woody vegetation all over the world. A preparation of mycelium of the fungus C. purpureum is registered under the trade name “Chontrol™ Paste” in the US and Canada for use as a biological control agent and has been tested as a stump treatment on many hardwood species (EPA Registration No. 74200-1, 2004 ; and PMRA Registration No. REG. 2004-09, 2004). Treatment of stumps with C. purpureum has been shown to be effective for suppression of resprouting on several species, most notably red alder (Alnus rubra).In Fall 2010, our research team established field trials near Brookings, Oregon to assess the bioherbicidal efficacy of C. purpureum on tanoak to inhibit resprouts which can harbor P. ramorum and serve as a source of inoculum. Early results showed that C. purpureum was able to colonize the stumps of tanoak following treatment.Research is underway to test various decay fungi such as C. purpureum and Ganoderma spp. on California bay laurel (Umbellularia californica) prior to field testing in California.

Publications

Biological control of tanoak resprouts using the fungus Chondrostereum purpureum. Marianne Elliott, Simon Shamoun, Grace Sumampong, Ellen Goheen, Alan Kanaskie, and Gary Chastagner. Poster presented at 59th WIFDWC, October 2011.

Contact: Gary Chastagner, 253-445-4528 | WSU Puyallup Research & Extension Center, 2606 West Pioneer, Puyallup, WA, 98371-4998 USA
Last updated January 2, 2013

Anderson Creek

January 21, 2015 gary.maguire

Anderson Creek

Site # 1002

First bait deployment on March 4, 2010 at Anderson Creek by Jenny Davidson, University of Hawaii

Location of bait bags, April 1, 2010. Photos by Jenny Davidson.

Baiting period	Bait leaf spp.	Phytophthora spp. and others identified
1	Rhododendron	P. gonapodyides (4), Trichoderma spp. (1), unknown (5)
1	Sword fern (Polystichum munitum)	P. gonapodyides (1), unknown (1)
2	Rhododendron	P. gonapodyides (4), Trichoderma spp. (1), fungus (cryptosporiopsis, dermateaceae, pezicula) (1), unknown (2)
2	Sword fern	P. gonapodyides (1), unknown (1)
3	Rhododendron	P. gonapodyides (3), unknown (5)
3	Sword fern	Pythium sp. or Py. undulatum (1), unknown (1)
4	Rhododendron	P. gonapodyides (6), unknown (5)
4	Dandelion (Taraxacum officinale)	Trichoderma spp, Fusarium spp.
5	Rhododendron	P. gonapodyides (8), unknown (4)
5	Horsetail (Equisetum spp)	unknown (4)
6	Rhododendron	P. gonapodyides (5), unknown (8)
6	Red alder (Alnus rubra)	P. gonapodyides (1), unknown (2)

Mainstem Nooksack river – information about the watershed Whatcom Salmon Recovery 2003

Contact: Gary Chastagner, 253-445-4528 | WSU Puyallup Research & Extension Center, 2606 West Pioneer, Puyallup, WA, 98371-4998 USA
Last updated January 2, 2013

Research

January 21, 2015 gary.maguire

Research Projects

Since 2003, the WSU Puyallup Ornamental Plant Pathology Program has been conducting research on Phytophthora ramorum relating to host range, epidemiology, and evaluating potential control options.

In response to industry concerns, WSU built a quarter-million-dollar biocontainment facility at Puyallup. This facility will greatly increase the capacity of WSU to address critical research questions relating to the establishment, host susceptibility, spread and management of P. ramorum. A molecular lab has also been established to enhance research relating to the detection, spread, and genetics of this pathogen.

An Overview of Phytophthora ramorum in Washington State

Gary A. Chastagner, Katie Coats, and Marianne Elliott

In Frankel, S.J.; Kliejunas, J.T.; Palmieri, K.M.; Alexander, J.M. tech. coords. 2013. Proceedings of the Sudden Oak Death Fifth Science Symposium. Gen. Tech. Rep. PSW-GTR-243. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 169 p.

Management of P. ramorum

Host testing

Nursery research

P. ramorum in waterways

Biology of P. ramorum – wild type and non-wild type isolates

Contact: Gary Chastagner, 253-445-4528 | WSU Puyallup Research & Extension Center, 2606 West Pioneer, Puyallup, WA, 98371-4998 USA
Last updated January 2, 2013

BOB Photos

January 20, 2015 gary.maguire


Sammamish River in Bothell. This is a fairly slow moving river that gets water inputs from residential, agricultural, and commercially developed areas.

Fishing for bait bag at site 13. A pole is useful when bait bags get carried away by the current.

Collecting water at site 13A ditch

Woodin Creek – site 21 (it was getting dark)

Preparing water samples for BOB and filtering

Filtration apparatus in lab

Collecting water at site 7. Water samples are collected in 100 ml aliquots and mixed, rather than collecting the entire 1L at once. This method works better in cases where inoculum density is low.

Ditch at site 13A – industrial site

Little Bear Creek – site 12. This creek was swollen from recent rainfall.

Collecting leaves from bait bag at Gig Harbor site

BOB setup. A whole Rhododendron leaf (not shown) is also added to the bottle containing 1L stream water and 20 small leaf baits. These baits are incubated in stream water and then plated onto Phytophthora selective media.

Culturing filter on selective media

The “Bottle O’ Bait” (BOB) method for detecting P. ramorum in water

January 20, 2015 gary.maguire

In January 2010, Steve Oak (US Forest Svc, Asheville, NC) and Jaesoon Hwang (Clemson University, Clemson, SC) visited western Washington to collect samples from streams known to contain P. ramorum and test out the BOB method, filtration, and leaf baiting for detecting P. ramorum. Dan Omdal (WADNR) and Marianne Elliott (WSU) took them to stream sites where leaf baits were deployed and assisted with collecting samples.

The BOB method will be very useful in situations where it is difficult to return to the site to collect more samples or where the water level in the stream is too low to use a bait bag.

See more photos here.

Contact: Gary Chastagner, 253-445-4528 | WSU Puyallup Research & Extension Center, 2606 West Pioneer, Puyallup, WA, 98371-4998 USA
Last updated January 2, 2013

Population genetics of P. ramorum in WA

January 20, 2015 gary.maguire

Population genetics of P. ramorum in Washington State

During the past four years (2005-2008), Phytophthora ramorum has been detected in 27 western Washington nurseries. To date, 314 P. ramorum isolates have been collected from the 27 nurseries, as well as two streams, a retention pond, and one landscape site, and genotyped using four microsatellite markers (PrMs5, Pr9C3, PrMs39 and PrMs45).

All three previously described lineages (EU1, NA1, and NA2) were detected in each of the four years. In this population, the EU1 lineage is represented by one genotype, the NA2 lineage is represented by one genotype, and the NA1 lineage is represented by four genotypes. The NA1 lineage was the most common, occurring in 24 nurseries, one landscape situation, and both streams. The NA2 lineage was detected at 10 nurseries and one stream, while the EU1 lineage was detected at five nurseries. The occurrence of the EU1 lineage in Washington has increased in frequency over the past four years while the overall number of P. ramorum sites and isolates has declined. In four of the five sites where the EU1 lineage occurred, the NA1 lineage was also detected at the same time. At one nursery in 2007, these two lineages were isolated from different branches on the same rhododendron plant. At another nursery in 2008, they were isolated from the same soil bait. Although no genotype detected to date possesses a hybrid of alleles from both the European (EU1) and North American (NA1 and NA2) lineages, the presence of the EU1 and NA1 lineages on the same plant and soil bait illustrates the need for a better overall understanding of the population structure of P. ramorum in nurseries to reduce the risk of hybridized species occurring as a result of sexual recombination.

The APHIS confirmed nursery protocol (CNP) appears to be effective in eradicating the pathogen from infected nurseries in some instances. Fifteen of the 27 positive nurseries were negative for P. ramorum in subsequent years after completing the CNP. On the other hand, 12 nurseries were repeatedly positive for two or more years in a row. At only one repeat-positive nursery did a new genotype appear in the second positive year that was not present in the nursery during the first positive year. Thus it is unclear if inoculum was persisting from year to year or if the same genotypes that were initially detected at 11 of the repeat nurseries was reintroduced in subsequent years. At the six nurseries showing the most genetic variability, three different genotypes were detected in a single year.

from the February 2009 COMTF newsletter

Contact: Gary Chastagner, 253-445-4528 | WSU Puyallup Research & Extension Center, 2606 West Pioneer, Puyallup, WA, 98371-4998 USA
Last updated January 2, 2013

Monitoring

January 15, 2015 gary.maguire

Monitoring for early detection of invasive Phytophthoras in WA State

Western Washington is a “high risk” area for diseases caused by P. ramorum and other Phytophthora species because of favorable environmental conditions and the abundance of susceptible host plants in wildland and urban areas. At present, P. ramorum has only been detected in or near nurseries in western Washington.

The spread of P. ramorum into the landscape will trigger a series of quarantines that will have a significant economic impact on the horticulture and forest products industry. Stream monitoring programs have been shown to be an effective approach to detect the spread of P. ramorum and focus eradication efforts to high risk areas, thus reducing the threat this pathogen poses to our landscape and forest ecosystems.

SOD monitoring in Washington:

SOD monitoring elsewhere:

SOD National Detection Survey (US Forest Service)

SOD monitoring in California (COMTF site)

P. ramorum surveys in the UK (Forestry Commission)

More information:

Stream monitoring for Phytophthora in Washington State, USA: a citizen science project. Presentation at IUFRO 125th Anniversary Congress, Freiburg, Germany Sept. 18-22, 2017.

Community-based stream monitoring for invasive Phytophthoras in western Washington. Marianne Elliott, Gary Chastagner, Katie Coats, Annie DeBauw, and Kathy Riley. Poster, March 2011.

P. ramorum detection and monitoring in western Washington waterways, 2010 . Daniel Omdal and Amy Ramsey-Kroll, WA DNR. Poster, Dec. 2010.

The BOB method for detecting P. ramorum in water

Population genetics of P. ramorum in WA state – research

Forest Phytophthoras of the World

Contact: Gary Chastagner, 253-445-4528 | WSU Puyallup Research & Extension Center, 2606 West Pioneer, Puyallup, WA, 98371-4998 USA
Last updated January 2, 2013

Long term sites

January 12, 2015 gary.maguire

Long term sites

Each site had two bait bags containing 10 leaves/sampling period. Bait leaves used were Rhododendron ‘Nova Zembla’ and a ‘wild card’ species of choice. Leaves were sliced in several locations along the midrib to allow for better colonization by Phytophthora. See individual sites for more detailed results. Of these ten leaves, five leaves were cultured and two isolates per leaf were identified using PCR-RFLP and sequencing if necessary, for a total of 10 samples per baiting period. Phytophthora gonapodiydes was found the most often. Unknowns are being sequenced.

1001 – Clarks Creek Downstream

1002 – Anderson Creek

1003 – Evans Creek

1006 – Dogfish Creek

Phytophthora species isolated from ‘wild card’ plants

Temperature data

Contact: Gary Chastagner, 253-445-4528 | WSU Puyallup Research & Extension Center, 2606 West Pioneer, Puyallup, WA, 98371-4998 USA
Last updated January 2, 2013