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Port-Orford-cedar (a) tree in urban area, (b) large, healthy tree in southern Oregon, (c) dead trees in forest along a creek in southwest Oregon, (d) dead and dying trees along Highway 101 in southwest Oregon, (e) resistant parent tree (510015) surrounded by dead Port-Orford-cedar. (Photo credits: Richard Sniezko, a to d; Chuck Frank, e)
Source publication
northwestern California and southwestern Oregon. It has been widely used in horticulture in both western North America and elsewhere. The accidental introduction of the non-native pathogen Phytophthora lateralis into North America and Europe has raised concerns about the future viability of POC in some forest ecosystems, in managed forests, and in...
Contexts in source publication
Context 1
... of P. lateralis is small, likely due to a genetic bottleneck from the original introduction of this pathogen from elsewhere ( Goheen et al. 2003), and this may bode well for durability of resistance. Recorded survival for a decade or more of many of the initial field selections in areas of high P. lateralis-caused mortality is encouraging ( fig. 1e). These trees could serve as permanent plots to help monitor resistance. In addition to the root dip testing, short-term testing using raised beds infested with P. lateralis has been used to test resistance ( Hansen et al., this proceedings). No change in efficacy of resistance is apparent in continued use of these raised beds for more ...
Context 2
... nurseries and non-federal landowners from 2003 to 2011 (Larry Miller, Oregon Department of Forestry, personal communication). Over 3.85 kg of seed (385,000 to 452,000 seed per kg, approximately 60 percent filled seed) has been dispersed (table 2). Most of the seed need has been for the western most portions of Oregon (Breeding Zones 110 and 125, fig. 1; table 2). Resistant seed is now being used by federal and non-federal land managers for reforestation and restoration (figs.8 and 9; table 2). Due to changing management practices on some federal lands, including reduced timber harvest, opportunities for using resistant POC seed in restoration and reforestation are now more limited, ...
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Citations
... Concerning Phytophthora species, control is hard and complicated, particularly if they are introduced into natural ecosystems. In these cases, protection and management strategies rely mainly on long-term resistance screening programs (Hansen et al., 2000;Sniezko et al., 2011), or application of potassium phosphite in the areas where it is still allowed (Hardy et al., 2001;Garbelotto et al., 2007;Jung et al., 2018). In nurseries and ornamental crops infections mainly originate from irrigation water (Hong et al., 2014) and infected soils and root systems of plants (Jung et al., 2016). ...
We examined essential oils (EOs) of Chamaecyparis lawsoniana and Thuja plicata (Cupressaceae), their antifeedant activity on Lymanthria dispar larvae and their antimicrobial activity. Studies of EOs showed that these two conifer species differed both in content of terpene classes and the major compounds. Total monoterpenes strongly dominated in T. plicata (96.4%), while C. lawsoniana was rich in both mono- and sesquiterpenes (40.8% and 30.3%, respectively) as well as in diterpenes (19.1%). The most dominant compounds of C. lawsoniana EO were: limonene (16.7%), oplopanonyl acetate (14.5%), beyerene (10.1%), and 13-epi-dolabradiene (6.7%). The dominant compound of T. plicata EOs was α-thujone (76.9%), followed by relatively small amounts of β- thujone (5.3%), sabinene (4.5%) and terpinene-4-ol (3.2%). The difference in EO compositions of the conifers was reflected on Lymantria dispar larvae performance. Larvae fed on the leaf discs treated by C. lawsoniana EO had a slight phagostimulatory effect at lower concentration shown by higher relative rate of food consumption and relative growth rate than the larvae in the control group. Contrastingly, leaf discs treated with EO of T. plicata EO had an antifeedant effect and lower relative consumption rate (RCR) and relative growth rate RGR than the larvae in the control group. Both tested EOs influenced substantially the colony growth of the subjected Phytophthora plurivora and P. quercina. Namely, 100% inhibitory effect was recorded at concentration of 0.1% in the case of C. lawsoniana EO, whereas of T. plicata colonies did not grow at 0.5% concentration. The implications of these findings and possibility of using the tested EOs in further experiments in vitro and in vivo are discussed.
... While seeds produced by initial ROD-resistant selections will satisfy the immediate need for resistant ʻōhiʻa in native forest restoration, selective breeding of the most resistant families and successive breeding of those progeny can improve resistance (Carson and Carson 1989;Sniezko et al. 2012). If only partial resistance exists, recurrent selection of individuals that show the highest levels of resistance could produce offspring with similarly high levels of resistance at a higher frequency. ...
Metrosideros polymorpha Gaud. (‘ōhi‘a) is the most abundant native forest tree in Hawai‘i and a keystone species of cultural, ecological, and economic importance. ‘Ōhi‘a forests, particularly on Hawaiʻi Island, are being severely impacted by Rapid ‘Ōhi‘a Death (ROD), which is caused by the fungal pathogens Ceratocystis lukuohia and C. huliohia. ROD is characterized by branch dieback, crown wilting, and mortality. Initial disease resistance screening of four varieties of M. polymorpha with C. lukuohia demonstrated that varieties may differ in susceptibility. Several survivors of field or screening-based infections still exist, providing strong impetus for the establishment of the ‘Ōhiʻa Disease Resistance Program (ʻŌDRP). Here, we outline a framework for guiding the ʻŌDRP throughout the process of identifying and developing ROD resistance in M. polymorpha and, possibly, all Hawaiian Metrosideros species. Core ʻŌDRP projects include: (1) evaluating and operationalizing methods for greenhouse-based production and screening of test plants; (2) greenhouse screening of seedlings and rooted cuttings sampled from native Metrosideros throughout Hawaiʻi; (3) establishing field trials to validate results from greenhouse assays; (4) understanding environmental and genetic drivers of resistance to characterize the durability of resistance to ROD; (5) developing remote sensing and molecular methods to rapidly detect ROD-resistant individuals; and (6) conducting breeding trials to improve the degree and durability of ROD resistance. Ultimately, the ʻŌDRP seeks to produce ROD-resistant material for the perpetuation of M. polymorpha across Hawai‘i, with the goal of preserving the ecology, culture, and communities that are dependent on this tree species.
... Several white pine species, including high elevation white pines, have now been bred for resistance to WPBR, making it possible to restore white pines in areas where these pines were previously endangered (Sniezko et al., 2014). Breeding and developing resistant Port-Orford-cedar (POC) for resistance to the exotic root pathogen Phytophthora lateralis (Zobel et al., 1985) is another success story (Sniezko et al., 2012). Planting resistant POC and developing operational use of multiple disease management practices have been credited with the recent downgrade of POC status from "vulnerable" to "near threatened" by the IUNC (Pike et al., 2021). ...
... The procedures of the highly successful long-term tolerance screening program of Chamaecyparis lawsoniana against Phytophthora lateralis in the USA could be a template for an ash tolerance screening programme (Hansen et al., 2000;Sniezko et al., 2011 ...
For the long‐term goal of improving planting success and reforestation of floodplain forests, an underbark inoculation test was performed using one‐year‐old seedlings from ten different half‐sib lines of narrow‐leaved ash (Fraxinus angustifolia) to examine the variability of host susceptibility to the ash dieback pathogen Hymenoscyphus fraxineus. Sizes of necrotic lesions, production of epicormic shoots and mortality was recorded in all inoculated seedlings 76 days after inoculation. Mortality of different half‐sib lines ranged between 13.3% and 80%. Only one of the tested half‐sib lines showed necrotic lesion sizes, production of epicormic sprouts and percentage of mortality substantially lower than all the other nine half‐sib‐lines of the respective symptom traits. About 20% of half‐sib lines had reduced only one of these three symptoms. The other 70% of tested half‐sib lines had large necrotic lesions, abundant occurrence of epicormic sprouts and high percentage of mortality. Mortality was also significantly influenced by seedling height at the time of inoculation with taller seedlings developing mortality more slowly than smaller seedlings. This study demonstrates significant differences in the susceptibility to H. fraxineus between different half‐sib lines of F. angustifolia and the influence of seedling height on the development of ash dieback.
... Large operational resistance screening trials began in the 1990s in which more detailed results, including some evidence for both QDR and MGR disease resistance emerged (Sniezko, 2004(Sniezko, , 2006. These trials were part of a comprehensive breeding program that was established at the USDA Forest Service's Dorena Genetic Resource Center (DGRC), Cottage Grove, Oregon, to aid in restoration and reforestation of C. lawsoniana (Sniezko et al., 2012b). ...
... The C. lawsoniana program to develop resistance to P. lateralis offers a successful and concrete example for those contemplating resistance programs in other species. Thousands of field selections were made initially, breeding zones established, several types of screening methodologies developed, tested, and utilized, field trials and seed orchards established (Hansen et al., 2012;Sniezko et al., 2012a;Sniezko et al., 2012b). The development of the program involved the participation of interdisciplinary teams of tree breeders, pathologists, foresters, and organizations, as well as the sustained support from several government agencies. ...
Societal Impact Statement
Non‐native pathogens and pests cause high mortality to tree species globally and may imperil the future viability of associated forest ecosystems. Phytophthora lateralis , an oomycete, causes Port‐Orford‐cedar root disease and is a major cause of mortality in the ecologically and economically important conifer species Chamaecyparis lawsoniana (Port‐Orford‐cedar). The P. lateralis resistance program shows promise to help stabilize C. lawsoniana in its native range of northwestern California and southwestern Oregon, USA, and serves as a leading example of disease resistance breeding in forest trees
Summary A non‐native, invasive pathogen, Phytophthora lateralis , has caused extensive mortality within the native range, northern California and southern Oregon USA, of Chamaecyparis lawsoniana (Port‐Orford‐cedar), as well as in horticultural and amenity plantings in the USA and Europe. Restoration of affected sites is contingent upon development of populations with genetic resistance. Naturally occurring genetic resistance has been identified in C. lawsoniana , and an active selective breeding program seeks to characterize and increase resistance levels.
Two seedling root dip inoculation trials, assessed for mortality for nearly three years each, are used to examine the types and levels of genetic resistance in C. lawsoniana . Most seedlings utilized in these trials are progeny of crosses from parent trees that exhibited apparent resistance to the disease in earlier trials.
Seedling trials suggest that both qualitative major gene and quantitative disease resistance occurs in C. lawsoniana . Both types of resistance to P. lateralis appear to be present at levels high enough to be immediately useful for restoration and reforestation. The data suggest that the qualitative resistance is conditioned by a single major gene (designated here as Pla ), but nothing is known about the number of genes involved in quantitative disease resistance.
Seedling progeny from resistant parent trees in containerized seed orchards are now being used for restoration and reforestation. Resistant seedlings or clones could also be used to re‐establish C. lawsoniana in urban forests.
... In many instances, intensive artificial selection of resistant trees is required since there is an insufficient amount of quantitative genetic variation to allow for natural recovery in forest populations (Ennos, 2015). Examples of where resistant trees have been identified and bred using intensive artificial selection include: inter-specific chestnut hybrids resistant to Cryphonectria parasitica (causal agent of chestnut blight) (Burnham, 1988), Port-Orford-cedar resistant to Phytophthora lateralis (causal agent of Port-Orford-cedar root rot) (Sniezko et al., 2012), and elm tolerant to Ophiostoma novoulmi (causal agent of Dutch elm disease) (Martín et al., 2015). ...
New approaches for identifying disease resistant trees are needed as the incidence of diseases caused by non-native and invasive pathogens increases. These approaches must be rapid, reliable, cost-effective, and should have the potential to be adapted for high-throughput screening or phenotyping. Within the context of trees and tree diseases, we summarize vibrational spectroscopic and chemometric methods that have been used to distinguish between groups of trees which vary in disease susceptibility or other important characteristics based on chemical fingerprint data. We also provide specific examples from the literature of where these approaches have been used successfully. Finally, we discuss future application of these approaches for wide-scale screening and phenotyping efforts aimed at identifying disease resistant trees and managing forest diseases.
... The considerable variation detected suggests that selecting the more resistant genotypes to PA and using them for resistance breeding might be successful in A. glutinosa, just as it has been in Chamaecyparis lawsoniana for P. lateralis resistance (Sniezko et al. 2012) and in E. marginata for P. cinnamomi resistance (Stukely et al. 2001). Moreover, the outcomes of Jung and Blaschke (2006) also indicate this is a possibility in P. alni. ...
Variation in natural susceptibility of the black alder population to Phytophthora xalni (PA), the oomycete pathogen causing a devastating disease of alder, and its possible relationship to geographic origin, was studied in vitro using branch inoculation tests. Ninety black alder genotypes from different regions of the Czech Republic and two isolates of PA were employed. Host susceptibility varied significantly. After
1 week of infection, the lesion surface areas ranged from 254 to 2051 mm2 and from 19 to 970 mm2 for the two isolates, respectively. The differences were also dependent on the geographical origin and altitude of the sites from which particular host genotypes were taken. These findings have important implications for restoration plantings and for PA resistance breeding programmes, as there is potential to make selections from natural populations.
... Different parts of the program are emphasized in different regions. There is a national and international quarantine and certified plant inspection program evolving to cut off pathways of spread through the nursery trade [86]. In Oregon, the effort is to slow the spread by eradication of new spot infections before they in turn become sources of inoculum [87]. ...
Species of Phytophthora are prominent in lists of emerging threats to forest ecosystems. We explore the conditions leading to and the consequences of the emergence of some Phytophthora species from their presumptive coevolved roles in undisturbed forest ecosystems to destructive agents as invasive forest pathogens. Phytophthora species are widespread, relatively abundant, very diverse, and poorly understood in many relatively undisturbed forest ecosystems. Three examples are examined in detail to illustrate the range of pathways to emergence and the varied consequences to forest environments. Phytophthora lateralis causes Port-Orford cedar root disease in western North America and now Europe. Phytophthora ramorum is causing unprecedented mortality in oak and tanoak forests in California, as the cause of sudden oak death, and is killing planted larch in the UK, and Phytophthora cinnamomi kills trees in parts of the world where it has been introduced. Active programs are underway in each case to manage, if not eliminate, their damage. In no case, however, has eradication been achieved. Prevention, by blocking initial introduction, has the highest probability of success.
... Genetic resistance within the wild population of C. lawsoniana was demonstrated in 1989 (7). Cedar trees that survived epidemics in the wild or in artificially infested raised beds have been tested for their resistance to P. lateralis using a variety of inoculation procedures (5). A program was initiated by the Dorena Genetic Resource Center (DGRC) USDA Forest Service (http://www.fs.usda.gov/goto/r6/dorena) in cooperation with Oregon State University (OSU) to develop this genetic resistance in C. lawsoniana through conventional breeding and to use resistant trees in seed orchards with the goal of providing resistant seedlings for forest regeneration (15,18). In repeated tests by DGRC and OSU, most POC trees prove very susceptible; susceptible seedling families showed only 0 to 10% survival using a variety of inoculation techniques. ...
... Resistant and susceptible "control" trees (Table 4) and seedling families are included in all resistance screening trials at DGRC and were included here. Parent trees, originally propagated from rooted cuttings, were maintained in the cedar clone bank at the Bureau of Land Management Tyrrell seed orchard in Oregon (15). Resistant control parent tree 117490 is highly resistant in repeated tests; rooted cuttings are seldom killed by the pathogen, and seedling progeny, whether from self-pollination or from control crosses with known susceptible parents, are also resistant. ...
... In that region, resistant individuals have been identified and characterized through controlled crosses and challenge inoculations with P. lateralis isolates from western North America. Resistant selections are incorporated into seed orchards and resistant seed is now available for operational use in western forests (15). It is important to know if newly described lineages of the pathogen from other regions of the world are virulent on the previously resistant genotypes of the host. ...
Phytophthora lateralis, the cause of Chamaecyparis lawsoniana root disease, was introduced in North America about 1950, 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.
... Genetic resistance within the wild population of C. lawsoniana was demonstrated in 1989 (7). Cedar trees that survived epidemics in the wild or in artificially infested raised beds have been tested for their resistance to P. lateralis using a variety of inoculation procedures (5). A program was initiated by the Dorena Genetic Resource Center (DGRC) USDA Forest Service (http://www.fs.usda.gov/goto/r6/dorena) in cooperation with Oregon State University (OSU) to develop this genetic resistance in C. lawsoniana through conventional breeding and to use resistant trees in seed orchards with the goal of providing resistant seedlings for forest regeneration (15,18). In repeated tests by DGRC and OSU, most POC trees prove very susceptible; susceptible seedling families showed only 0 to 10% survival using a variety of inoculation techniques. ...
... Resistant and susceptible "control" trees (Table 4) and seedling families are included in all resistance screening trials at DGRC and were included here. Parent trees, originally propagated from rooted cuttings, were maintained in the cedar clone bank at the Bureau of Land Management Tyrrell seed orchard in Oregon (15). Resistant control parent tree 117490 is highly resistant in repeated tests; rooted cuttings are seldom killed by the pathogen, and seedling progeny, whether from self-pollination or from control crosses with known susceptible parents, are also resistant. ...
... In that region, resistant individuals have been identified and characterized through controlled crosses and challenge inoculations with P. lateralis isolates from western North America. Resistant selections are incorporated into seed orchards and resistant seed is now available for operational use in western forests (15). It is important to know if newly described lineages of the pathogen from other regions of the world are virulent on the previously resistant genotypes of the host. ...
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.
