First Report of Phytophthora ramorum Infecting Mistletoe in California

2011 ◽  
Vol 12 (1) ◽  
pp. 38 ◽  
Author(s):  
Kathleen L. Riley ◽  
Gary A. Chastagner
Keyword(s):  
Douglas Fir ◽  
Black Walnut ◽  
Phytophthora Ramorum ◽  
Sudden Oak Death ◽  
Christmas Tree ◽  
Tree Plantation ◽  
First Report ◽  
Plant Parts ◽  
White Fir ◽  
Zoospore Suspension

In 2005 and 2006, white fir and Douglas-fir growing in a Christmas tree plantation near Los Gatos, CA, under a black walnut tree infected with mistletoe tested positive for Phytophthora ramorum, the cause of Sudden Oak Death. Isolation from a symptomatic mistletoe inflorescence stalk was positive for P. ramorum. In 2007, fresh mistletoe leaves, stems, inflorescence stalks, and berries were inoculated with a zoospore suspension of the mistletoe isolate. All of the plant parts developed symptoms, and P. ramorum was isolated from each of them. This is the first report of an infection of a hemiparasite with P. ramorum. Accepted for publication 20 January 2011. Published 9 February 2011.

First Report of Phytophthora ramorum Infecting Grand fir in California

2011 ◽  
Vol 12 (1) ◽  
pp. 37
Author(s):  
Kathleen L. Riley ◽  
Gary A. Chastagner ◽  
Cheryl Blomquist
Keyword(s):  
Phytophthora Ramorum ◽  
Christmas Tree ◽  
Native Range ◽  
Tree Plantation ◽  
Koch’S Postulates ◽  
First Report ◽  
Stem Lesions ◽  
Koch's Postulates

Phytophthora ramorum was detected on grand fir in 2003 and 2005 in a Christmas tree plantation near Los Gatos, CA, in association with infected California bay laurel. Isolates derived from stem lesions were used to inoculate grand fir seedlings in two tests. Isolations from lesions on inoculated plants were positive for P. ramorum in both tests. This work provides the completion of Koch's postulates to establish grand fir as a host of P. ramorum. The potential for grand fir to be infected within its native range is unknown. Accepted for publication 1 February 2011. Published 1 April 2011.

scholarly journals First Report of Phytophthora ramorum Lineage EU1 Infecting Douglas Fir and Grand Fir in Oregon

Plant Disease ◽  
2018 ◽  
Vol 102 (2) ◽  
pp. 455-455 ◽  
Author(s):  
J. M. LeBoldus ◽  
K. L. Sondreli ◽  
W. Sutton ◽  
P. Reeser ◽  
S. Navarro ◽  
...  
Keyword(s):  
Douglas Fir ◽  
Phytophthora Ramorum ◽  
First Report

scholarly journals First report of leaf blight caused by Phytophthora ramorum on cherry laurel (Prunus laurocerasus) in Washington State, USA.

Plant Disease ◽  
2020 ◽  
Author(s):  
Marianne Elliott ◽  
Lucy Rollins ◽  
Tyler Bourret ◽  
Gary Chastagner
Keyword(s):  
The United States ◽  
Washington State ◽  
Phytophthora Ramorum ◽  
Sterile Water ◽  
Long Distance ◽  
First Report ◽  
Plant Nursery ◽  
Cherry Laurel ◽  
Zoospore Suspension ◽  
Prunus Laurocerasus

In April 2014, Phytophthora ramorum (Werres, De Cock & Man in't Veld) was recovered from symptomatic foliage of cherry laurel (Prunus laurocerasus) at an ornamental plant nursery in Washington State. Cherry laurel, also known as English laurel, is widely propagated in WA because it is commonly used in landscaping. It is invasive in forests near the urban/wildland interface in the western US and in Europe (Rusterholz et al. 2018). Given its popularity as an ornamental species, the potential of this host to spread P. ramorum is of regulatory concern due to possible long distance spread to other states via nursery stock. Foliar symptoms consisted of dark brown lesions near wounds or around leaf margins where water collected. Shot-hole symptoms characterized by abscission zones and dropping of infected tissues were also observed. Lesions expanded beyond the margin of the shot-hole in some cases (Figure S1A). Phytophthora was isolated from symptomatic foliage by surface-sterilizing leaf pieces in 0.6% sodium hypochlorite and 2 rinses in sterile water. They were plated on PARP medium (Ferguson and Jeffers 1999). After 2-3 days, a slow-growing dense colony with coralloid hyphae was isolated onto V8 agar. P. ramorum was identified by observing morphological features (Figure S1B). Colony and spore morphology matched that of P. ramorum (Werres et al. 2001). The isolate was confirmed as P. ramorum by PCR and sequencing of ITS and COX1 regions using primers ITS1/ITS4 (White et al. 1990) and COX1F1/COX1R1 (Van Poucke et al. 2012). Sequences were submitted to GenBank (accession nos. ITS MT031969, COX1 MT031968). BLAST results showed at least 99% similarity with sequences of P. ramorum (ITS, KJ755124 [100%]; COX1, EU124926 [99%]). Multilocus genotyping with microsatellite markers placed the isolate in the EU1 clonal lineage. Pathogenicity of P. ramorum on cherry laurel was confirmed by completing Koch's Postulates using the isolate taken from this host. Two trials were done in a biocontainment chamber (USDA-APHIS permit # 65857) since P. ramorum is a quarantine pathogen and greenhouse trials could not be conducted, using detached stems from mature, visibly healthy cherry laurel plants growing in a landscape. Phytophthora ramorum inoculum was grown on V8A plates at 20®C for 2 weeks until sporangia were abundant. A zoospore suspension was produced by flooding plates with 7 ml sterile water, incubating for 2 hours at 5®C, then 1 hour at 24®C. Zoospores were observed with light microscopy, quantified with a hemocytometer and diluted to 1 x 104 zoospores/ml. A 10 µl droplet was placed at 3 wounded and 3 unwounded sites on 4 leaves per branch. In addition, a set of samples was inoculated by dipping foliage into the zoospore suspension for 30 seconds. A set of controls was mock inoculated using sterile water. Four branches per inoculation treatment were used and the trial was repeated once. Inoculated plant materials were incubated in moist chambers for 3-5 days at 20®C. Free moisture was present on foliage upon removal. Symptom development was assessed after incubation in the biocontainment chamber at 20®C for 7 days (Figure S1C). Phytophthora ramorum was reisolated from symptomatic tissue and the recovered culture was verified morphologically and by PCR and sequencing. It was isolated more often from foliage dipped in zoospore suspension than droplet inoculated, and more from wounded than unwounded sites. None of the water-inoculated controls were positive for P. ramorum. The presence of P. ramorum was also confirmed with DNA extraction from surface-sterilized symptomatic foliage followed by PCR and sequencing of the COX1 gene (EU124926, 100%) (Figure S2). To our knowledge, this is the first report of P. ramorum naturally infecting cherry laurel in the United States. Acknowledgements This work was supported by the USDA National Institute of Food and Agriculture, McIntire-Stennis project 1019284 and USDA APHIS Cooperative Agreement AP17PPQS&T00C070 Literature cited Ferguson and Jeffers, 1999. Plant Disease 83:1129-1136 Van Poucke, K. et al. 2012. Fungal Biology 116: 1178-1191. http://dx.doi.org/10.1016/j.funbio.2012.09.003 Werres, S. et al. 2001. Mycol. Res. 105:1155-1165. White, T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA.

First Report of Phytophthora ramorum Infecting Camellia Flower Buds in North America

2006 ◽  
Vol 7 (1) ◽  
pp. 52
Author(s):  
Steve A. Tjosvold ◽  
David L. Chambers ◽  
Samantha L. Thomas ◽  
Cheryl L. Blomquist
Keyword(s):  
North America ◽  
North American ◽  
Phytophthora Ramorum ◽  
Sudden Oak Death ◽  
Flower Buds ◽  
Flower Bud ◽  
First Report ◽  
The North ◽  
Landscape Plants ◽  
North American Genotype

Camellias are important nursery and landscape plants and are known to be highly susceptible hosts of Phytophthora ramorum, the pathogen that causes Sudden Oak Death. This is the first report of camellia flower bud infection in the field with the North American genotype of P. ramorum Accepted for publication 31 May 2006. Published 25 August 2006.

Phytophthora ramorum Infects Hazelnut, Vine Maple, Blue Blossom, and Manzanita Species in California

2008 ◽  
Vol 9 (1) ◽  
pp. 50
Author(s):  
Matthew V. DiLeo ◽  
John C. Bienapfl ◽  
David M. Rizzo
Keyword(s):  
Plant Species ◽  
Host Species ◽  
Phytophthora Ramorum ◽  
Sudden Oak Death ◽  
New Host ◽  
First Report ◽  
Species Overlap ◽  
Natural Hosts ◽  
Symptomatic Tissue ◽  
New Host Species

Phytophthora ramorum was isolated from symptomatic tissue of California hazelnut, vine maple, blue blossom, and two species of manzanita. This is the first report of these plant species as natural hosts of P. ramorum. The native ranges of these new host species overlap considerably with regions that are highly favorable to P. ramorum epidemics. It is unknown how these newly-identified hosts affect the epidemiology of sudden oak death in California ecosystems or the spread of P. ramorum into un-infested areas. Accepted for publication 15 November 2007. Published 18 January 2008.

scholarly journals Five-Year Thinning Response of an Overgrown Douglas-Fir Christmas Tree Plantation

2004 ◽  
Vol 19 (3) ◽  
pp. 171-174
Author(s):  
S. Hummel ◽  
R. Hummel
Keyword(s):  
Douglas Fir ◽  
Planting Density ◽  
Christmas Tree ◽  
Tree Plantation ◽  
Quadratic Mean ◽  
Density Area ◽  
Mean Diameter ◽  
Plantation Age ◽  
Quadratic Mean Diameter

Abstract A 15-year-old Douglas-fir Christmas tree plantation in western Oregon was thinned in 1996 according to regional sawtimber conversion guidelines. The plantation comprised two strata, distinguished by initial planting density (Area 1 = 5 × 5 ft and Area 2 = 10 × 10 ft). Unthinned control plots were established in both Area 1 and Area 2 at the time of the thinning treatment. Five years later, the quadratic mean diameter (QMD) in Area 1 (thinned) was 6.4 in. versus 5.2 in. in Area 1 (unthinned), while in Area 2 (thinned) the QMD was 11.4 in. compared to 9.3 in. in Area 2 (unthinned). Over the same period, the volume/ac in Area 1 (thinned) (1,080 ft3/ac) was nearly twice that of Area 1 (unthinned) (576 ft3/ac). In contrast, the volume/ac in Area 2 (thinned) (2,318 ft3/acre) was almost half that of Area 2 (unthinned) (4,264 ft3/ac). These results suggest that while thinning was timely for Area 1, the thinning treatment could have been delayed for Area 2. By plantation age 30, the treated units in Area 1 and Area 2 have estimated yields of 9.6 and 11.6 thousand bd ft (mbf), respectively, with no additional thinning. Given 2002 average prices for #3 sawmill grade logs, gross return at age 30 would range between $5,000 and $6,000/ac. West. J. Appl. For. 19(3):171–174.

ESTIMATION OF GROWTH – TIME TEMPERATURE CHARACTERISTICS FOR ISOLATES OF FOMES PINI, A HEART ROT FUNGUS

1964 ◽  
Vol 42 (12) ◽  
pp. 1635-1652 ◽  
Author(s):  
Lee A. Paine ◽  
Gideon Schwarzbart ◽  
William G. O'Regan
Keyword(s):  
Regression Analysis ◽  
Cross Section ◽  
Growth Pattern ◽  
Storage Temperature ◽  
Three Dimensional ◽  
Douglas Fir ◽  
Growth Time ◽  
Optimum Temperature ◽  
Analysis Techniques ◽  
White Fir

Regression analysis techniques were applied to an estimation of three-dimensional surfaces representing the growth of Fomes pini as a function of time and temperature. These methods were judged to be valuable in their economy of data and in their provision of readily available plotting points for any desired cross section of the surface.The growth pattern of F. pini taken from Douglas fir was distinct from that of the form of F. pini found on nearby white fir. Growth of isolates from Douglas fir was more than twice that of white fir isolates after 18 days at near-optimum temperatures on malt agar. Estimates of growth trends and optimum temperatures were examined both for individual isolates of F. pini and for averages of isolates from the two host species, Douglas fir and white fir. Results suggest that chronological changes in the optimum temperature may be affected by the relation between the storage temperature preceding initial measurements and the terminal optimum temperature.

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