Update on the 35-year expansion of the invasive root pathogen,Phytophthora lateralis, across a landscape of Port Orford cedar (Chamaecyparis lawsoniana)

2014 ◽  
Vol 45 (2) ◽  
pp. 165-168 ◽  
Author(s):  
E. S. Jules ◽  
C. M. Steenbock ◽  
A. L. Carroll
Keyword(s):  
Root Pathogen ◽  
Phytophthora Lateralis ◽  
Chamaecyparis Lawsoniana ◽  
Port Orford Cedar

scholarly journals Root Rot of Juniperus and Microbiota by Phytophthora lateralis in Oregon Horticultural Nurseries

Plant Disease ◽  
2020 ◽  
Vol 104 (5) ◽  
pp. 1500-1506
Author(s):  
Ebba K. Peterson ◽  
Franziska Rupp ◽  
Joyce Eberhart ◽  
Jennifer L. Parke
Keyword(s):  
Root Rot ◽  
Internal Transcribed Spacer ◽  
Major Gene ◽  
Resistance Breeding ◽  
Its2 Region ◽  
Phytophthora Spp ◽  
Major Gene Resistance ◽  
Phytophthora Lateralis ◽  
Chamaecyparis Lawsoniana ◽  
Port Orford Cedar

Widespread symptoms of root rot and mortality on Juniperus communis and Microbiota decussata were observed in two horticultural nurseries in Oregon, leading to the isolation of a Phytophthora sp. from diseased roots. Based on morphology and sequencing the internal transcribed spacer ITS1-5.8S-ITS2 region, isolates were identified as the invasive pathogen Phytophthora lateralis, causal agent of Port-Orford-cedar (POC; Chamaecyparis lawsoniana) root disease. Additional sequencing of the cytochrome c oxidase subunit 1 and 2 genes identified all isolates as belonging to the PNW lineage. Utilizing recovered isolates plus a POC-wildlands isolate and susceptible POC as controls, we completed Koch’s postulates on potted Juniperus and Microbiota plants. Nursery isolates were more aggressive than the forest isolate, which was used in the POC resistance breeding program. Increased aggressiveness was confirmed using a branch stem dip assay with four POC clones that differed in resistance, although no isolate completely overcame major-gene resistance. Isolates were sensitive to mefenoxam, a fungicide commonly used to suppress Phytophthora spp. growth in commercial nurseries. Although POC resistance is durable against these more aggressive nursery isolates, the expanded host range of P. lateralis challenges POC conservation through the continued movement of P. lateralis by the nursery industry.

Phytophthora lateralis. [Distribution map].

2012 ◽  
Author(s):  
Keyword(s):  
British Columbia ◽  
North America ◽  
Northern Ireland ◽  
Geographical Distribution ◽  
Distribution Map ◽  
Phytophthora Lateralis ◽  
Chamaecyparis Lawsoniana ◽  
Port Orford Cedar ◽  
New Distribution ◽  
Distribution In Europe

Abstract A new distribution map is provided for Phytophthora lateralis Tucker & Milbrath. Oomycota: Peronosporales. Hosts: Port Orford cedar (Chamaecyparis lawsoniana) and other Chamaecyparis species. Information is given on the geographical distribution in Europe (France; Ireland; Netherlands; and England and Wales, Northern Ireland and Scotland, UK), Asia (Taiwan) and North America (British Columbia, Canada, and California, Florida, Oregon and Washington, USA).

scholarly journals Susceptibility of Pacific Yew to Phytophthora lateralis

Plant Disease ◽  
1997 ◽  
Vol 81 (12) ◽  
pp. 1400-1404 ◽  
Author(s):  
Marion S. Murray ◽  
Everett M. Hansen
Keyword(s):  
Root Colonization ◽  
Field Survey ◽  
Root Hairs ◽  
Lesion Length ◽  
New Host ◽  
Root Pathogen ◽  
Phytophthora Lateralis ◽  
Southwest Oregon ◽  
Port Orford Cedar

In 1991, Pacific yew was reported as a new host for Phytophthora lateralis, an aggressive root pathogen thought previously to be specific to Port Orford cedar. This study was designed to compare the pathogenicity of P. lateralis on the two hosts through seedling, stem, branch, and rootlet inoculations, and field survey. Mortality of inoculated plants averaged 72% for cedar and 4% for Pacific yew, and root colonization by P. lateralis was significantly greater in cedar seedlings than in Pacific yew seedlings. Lesion length on the cedar seedling stems was twice the lesion length on Pacific yew stems, and cedar branches had lesions four times longer than Pacific yew branches. Abundant zoospore aggregation occurred on cedar rootlets along the zone of elongation and the region of maturation. In comparison, far fewer zoospores encysted on Pacific yew rootlets, and they were concentrated on the root hairs. A field survey along 0.8-km stretches of three infested streams in southwest Oregon and northwest California revealed a total of 1,199 dead Port Orford cedar (46% mortality), and 86 dead Pacific yew (10% mortality). We conclude that Pacific yew is less susceptible to P. lateralis than Port Orford cedar.

scholarly journals Genetic resistance to Phytophthora lateralis in Port‐Orford‐cedar ( Chamaecyparis lawsoniana ) – Basic building blocks for a resistance program

2019 ◽  
Vol 2 (1) ◽  
pp. 69-83
Author(s):  
Richard A. Sniezko ◽  
Jeremy S. Johnson ◽  
Paul Reeser ◽  
Angelia Kegley ◽  
Everett M. Hansen ◽  
...  
Keyword(s):  
Genetic Resistance ◽  
Building Blocks ◽  
Phytophthora Lateralis ◽  
Chamaecyparis Lawsoniana ◽  
Port Orford Cedar

scholarly journals First Confirmation of Phytophthora lateralis in Europe

Plant Disease ◽  
1999 ◽  
Vol 83 (6) ◽  
pp. 587-587 ◽  
Author(s):  
E. M. Hansen ◽  
Jean-Claude Streito ◽  
Claude Delatour
Keyword(s):  
Culture Collection ◽  
Western North America ◽  
American Phytopathological Society ◽  
Woody Ornamentals ◽  
Short Stalk ◽  
Wide Range ◽  
Short Pedicel ◽  
Phytophthora Lateralis ◽  
Chamaecyparis Lawsoniana ◽  
Port Orford Cedar

Phytophthora lateralis, a pathogen of Chamaecyparis lawsoniana (Port-Orford cedar or Lawson's cypress), was confirmed in France, but isolates from Germany identified as P. lateralis or “similar to” P. lateralis proved to be P. gonapodyides. Previously, P. lateralis was known only from western North America, where it has been destructive in nurseries, ornamental plantings, and the forest since its introduction about 1920 (1). Reports from other locations have proved to be misidentifications or impossible to confirm. In France, P. lateralis was isolated and identified from C. lawsoniana on two occasions (1996 and 1998) in different parts of the country, probably stemming from a single original infestation of young, potted, greenhouse-propagated cedars in a commercial nursery. German isolates were from an old culture collection and from irrigation water in a nursery growing a wide range of woody ornamentals. Identifications were confirmed by comparison (2) with authentic isolates. P. lateralis isolates from France and Oregon formed laterally proliferating, elongated obpyriform sporangia that under the conditions of our tests could be dislodged by agitation, leaving a short pedicel. Also, brown chlamydospores formed laterally on the hyphae or terminally on a short stalk and oospores were not formed on standard media. Radial growth was about 2 mm per day. In contrast, sporangia of German isolates and known P. gonapodyides isolates were similar. They exhibited nested pro liferation, were broader than P. lateralis sporangia, and were not readily dehiscent. Some P. gonapodyides isolates, including those from Germany, formed chlamydospores, but these were nearly all catenulate and not lateral, and isolates grew faster (3 to 4 mm per day). Pathogenicity was tested by stem inoculation of C. lawsoniana. P. lateralis from France and Oregon produced lesions averaging 4.7 cm after 2 months (range 2.0 to 8.1 cm, six replicates per isolate, five isolates) while the six replicates of the two German isolates averaged 1.2- and 1.6-cm lesion lengths. Furthermore, sequences of internal transcribed spacer (ITS) DNA from French and Oregon P. lateralis isolates were identical, while sequences of German isolates were similar to P. gonapodyides (J. Duncan and D. Cooke, personal communiation). P. lateralis is a dangerous pathogen of C. lawsoniana and is also pathogenic to Taxus spp. (1), although less aggressive on this host. If established, it would be a serious threat to the widespread ornamental plantings and scattered forest plantations of C. lawsoniana in Europe. References: (1) E. M. Hansen and K. J. Lewis. Compendium of Conifer Diseases. American Phytopathological Society, 1997. (2) C. M. Tucker and J. A. Milbrath. Mycologia 34:94, 1942.

Root and aerial infections of Chamaecyparis lawsoniana by Phytophthora lateralis: a new threat for European countries

2010 ◽  
Vol 41 (5) ◽  
pp. 417-424 ◽  
Author(s):  
C. Robin ◽  
D. Piou ◽  
N. Feau ◽  
G. Douzon ◽  
N. Schenck ◽  
...  
Keyword(s):  
European Countries ◽  
Phytophthora Lateralis ◽  
Chamaecyparis Lawsoniana

scholarly journals Pathogenicity of Phytophthora lateralis Lineages on Different Selections of Chamaecyparis lawsoniana

Plant Disease ◽  
2015 ◽  
Vol 99 (8) ◽  
pp. 1133-1139 ◽  
Author(s):  
C. Robin ◽  
C. Brasier ◽  
P. Reeser ◽  
W. Sutton ◽  
A. Vannini ◽  
...  
Keyword(s):  
North America ◽  
Evolutionary History ◽  
Wild Population ◽  
Lesion Length ◽  
Asian Origin ◽  
Genetic Lineages ◽  
Inoculation Techniques ◽  
History Of ◽  
Phytophthora Lateralis ◽  
Chamaecyparis Lawsoniana

Phytophthora lateralis, the cause of Chamaecyparis lawsoniana root disease, was introduced in North America about 1920, and has since killed trees along roads and streams throughout the tree’s range. Recent results suggest an Asian origin for this oomycete and four genetic lineages were identified. This raised questions for the genetic exapted resistance demonstrated in 1989 within the wild population of C. lawsoniana but with only one P. lateralis lineage. The main goal of the present research was to test the durability of the demonstrated resistance and to compare the pathogenicity of isolates representing the four lineages. No breakdown of resistance was observed in five separate tests using different inoculation techniques, resistant and susceptible C. lawsoniana trees, and seedling families. Differences in mortality and lesion length were observed between the lineages. The higher aggressiveness of isolates of the TWJ and PNW lineages and the lower aggressiveness of the TWK lineage are discussed in view of the hypotheses on the history of spread and evolutionary history of the P. lateralis lineages.

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