Download or read book An Evaluation of Phytophthora Root Rot of Port Orford Cedar in California written by J. Kliejunas and published by . This book was released on 1980 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Phytophthora Root Rot of Port Orford Cedar written by L. E. Roth and published by . This book was released on 1972 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Port Orford cedar Root Disease written by Lewis F. Roth and published by . This book was released on 1987 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Port Orford cedar Root Rot written by and published by . This book was released on 1983 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Biological Evaluation of Port Orford cedar Root Rot on the Gasquet Ranger District Six Rivers National Forest written by John T. Kliejunas and published by . This book was released on 1985 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ecology Pathology and Management of Port Orford cedar Chamaecyparis Lawsoniana written by Donald B. Zobel and published by . This book was released on 1985 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Resistance Screening of Port orford Cedar to Phytophthora Lateralis Root Rot written by Everett M. Hansen and published by . This book was released on 1983 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Office Report written by Earl E. Nelson and published by . This book was released on 1964 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Biological Evaluation of Port Orford cedar Root Disease Infestation Near Camp Six Gasquet RD written by Gregg DeNitto and published by . This book was released on 1991 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Phytophthora Root Rot of Port Orford Cedar written by L. E. Roth and published by . This book was released on 1972 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Port Orford cedar Root Disease written by John T. Kliejunas and published by . This book was released on 2004 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Road Networks Timber Harvest and the Spread of Phytophthora Root Rot Infestations of Port Orford cedar in Southwest Oregon written by William C. Clark and published by . This book was released on 2011 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: Phytophthora lateralis is the causal agent of cedar root rot, a fatal forest pathogen whose principal host is Chamaecyparis lawsoniana (Port-Orford-cedar), a predominantly riparian-restricted endemic tree species of ecological, economical, and cultural importance to coastal Oregon and California. Local scale distribution of P. lateralis is thought to be associated with timber harvest and road-building disturbances. However, knowledge of the landscape-scale factors that contribute to successful invasions of P. lateralis is also important for effective land management of Port-Orford-cedar. P. lateralis is able to infest in wet conditions via stream networks (zoospore) and dry conditions via road networks (resting spore). This study tested the hypothesis that vehicles spread P. lateralis by relating its distribution to traffic intensive, anthropogenic disturbances (i.e. a road network, timber harvest) over a 31-yr period in a 3,910-km2 portion of the Rogue River-Siskiyou National Forest in the Siskiyou Mountains of Oregon. Indices of road disturbance (presence/absence, configuration, length, density, road-stream network connectivity) and timber harvest (presence/absence, area, density, frequency) were related to locations of infested cedar populations from a USFS survey dataset using a geographic information system (GIS). About 40% of 934 7th-field catchments were infested with the pathogen. Total road length of the study site was 5,070 km; maximum road density was 8.2 km/km2 and averaged 1.6 km/km2 in roaded catchments (n = 766). Timber activities extracted 17,370 ha (2,338 cutting units) of forest across 509 catchments; 345 catchments were cut [greater or equal to] twice. Maximum harvest density was 0.92 km2/km2 ([mean] = 0.04). Both road networks and timber harvest patchworks were significantly related to cedar root rot heterogeneity. Chi-squared contingency tables showed that infestation rates were 2.2 times higher in catchments with roads compared to roadless catchments and 1.4 times higher in catchments with road-stream intersections compared to those that were unconnected. Infestation was twice as likely in catchments with both harvest and road presence than road presence alone. Single-variable logistic regression showed that a one percent increase in harvest density increased infestation odds 25% and a one-unit (km/km2) increase in road density increased infestation odds 80%. Road and stream network configuration was also important to pathogen distribution: 1) uninfested catchments are most likely to be spatially removed from infested, roaded catchments, 2) only 11% of 287 roaded catchments downstream of infested, roaded catchments were uninfested, and 3) only 12% of 319 catchments downstream of infested catchments were uninfested. Road networks and timber harvest patchworks appear to reduce landscape heterogeneity by providing up-catchment and down-catchment access to host populations by linking pathogenic materials to the stream network. Timber harvest data suggest that while infestation risk to Port-Orford-cedar populations remains high, management policies may have curbed infestation risk in timber-harvested catchments; if this is a result of specific P. lateralis mitigation policies adopted in the late 1980's or broader, region-wide conservation policies (i.e. the Northwest Forest Plan) is yet unclear.

Download or read book Management of Port Orford cedar and Its Influence on Phytophthora Root Rot written by Thomas T. Lawson and published by . This book was released on 1983 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Quantitative Risk Assessment of Port Orford Cedar Root Disease in the Smith River National Recreation Area written by William David Ritts and published by . This book was released on 2003 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Coos Bay District Area Resource s Management Plan RMP written by and published by . This book was released on 1994 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Port Orford cedar and Phytophthora Lateralis written by Michael G. McWilliams and published by . This book was released on 2000 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: Port-Orford-cedar (Chamaecyparis lawsoniana) is a forest tree native to a small area of Oregon and California. A root disease caused by Phytophthora lateralis causes widespread mortality of Port-Orford-cedar. This dissertation examines three important elements of the Port-Orford-cedar P. lateralis pathosystem related to breeding for disease resistance: use of resistant rootstocks to maintain genotypes of Port-Orford-cedar for breeding; the heritability and genetic basis of disease resistance; and variability in virulence and DNA fingerprint among a sample of P. lateralis isolates. Port-Orford-cedar was reciprocally grafted to western redcedar (Thuja plicata), incense cedar (Calocedrus decurrens), and Alaska yellow-cedar (Chamaecyparis nootkatensis). Port-Orford-cedar scion graft success was moderate with western redcedar and incense cedar, but extreme overgrowth of the rootstock by the scion indicated incompatibility. Xylem union was good, but phloem union was incomplete or lacking. Nearly all Port-Orford-cedar rootstocks and seedlings exposed to P. lateralis died of root disease. Four percent of the Alaska yellow-cedar exposed also died, confirming this tree as a host for P. lateralis. Resistance of Port-Orford-cedar to P. lateralis is rare. A small number of trees have been identified exhibiting resistance. A number of families were tested to determine the genetic basis for resistance. Estimates of narrow-sense and family mean heritability of resistance, as exhibited by restriction of lesion length after inoculation, were determined. Both narrow-sense and family mean heritabilities were between 0.61 and 0.98 in most tests. Between 21% and 32% of the variance was due to differences among families. Thirteen isolates of P. lateralis were collected from three hosts throughout the geographic range of the fungus. Variation in growth rate on artificial media at three temperatures, virulence when used to inoculate Port-Orford-cedar, and DNA fingerprint were compared. There were significant differences in growth rate among isolates at 24C, but fewer differences at lower temperatures and on a rich medium. One isolate produced significantly shorter lesions in three different inoculation tests. Isolates differed at only two of 189 bands produced by Inter Simple Sequence Repeat (ISSR) DNA primers, indicating very little genetic variation among isolates.

Download or read book Developing Techniques for Evaluating the Susceptibility of Root disease Resistant Port Orford Cedar to Foliar and Stem Canker Diseases written by Danielle K. H. Martin and published by . This book was released on 2009 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since around 1923 Port-Orford-cedar (Chamaecyparis lawsoniana (A. Murray) Parl.) has been affected by Phytophthora root disease caused by the virulent introduced pathogen Phytophthora lateralis. A systematic resistance testing and breeding program located at the USDA Forest Service Dorena Genetic Resource Center in Cottage Grove, Oregon was initiated in 1997 with the goal of producing Phytophthora root disease resistant planting stock suitable for replacing wild native POC killed by the disease. Although families of Port-Orford-cedar have been identified as having a heritable form of resistance to Phytophthora lateralis, there is concern that susceptibility to other pathogens of Port-Orford-cedar, such as Seiridium sp. and Stigmina thujina, could compromise the success of deploying root disease resistant planting stock. This thesis examines methods used to evaluate the heritability of susceptibility of Port-Orford-cedar families in the Phytophthora root disease resistance breeding program to infection and disease caused by species of Seiridium and Stigmina thujina. Inoculation studies were undertaken to investigate the feasibility of developing protocols for screening Phytophthora root disease resistant POC for resistance to cypress canker caused by species of Seiridium and foliage blight caused by Stigmina thujina. Procedures were developed for culturing the pathogens, producing viable spores, and developing inoculation and disease rating procedures. In addition, the species of Seiridium associated with cypress canker of Port-Orford-cedar in Oregon was examined by observing morphological characteristics and comparing ß-tubulin and histone gene sequences. Cypress canker symptom severity was compared among 30 POC families with differing susceptibility to Phytophthora root disease. Seedlings were wound inoculated with cultures of a Seiridium sp. isolated from symptomatic POC and resulting symptoms scored monthly over the following 12 months. Symptoms of infection began to develop within two months after inoculation. Symptoms began as slight chlorosis of foliage above the site of inoculation, progressed to a darker browning of foliage, and finally resulted in seedling death. One year post inoculation about 71% of seedlings had been killed. Average between-family mortality ranged from 46 to 89% with a grand mean mortality of 52%. A multifactor ANOVA showed a significant variation in mortality among families. No correlation between resistance to Seiridium and resistance to P. lateralis was found. Variation in susceptibility to Stigmina foliage blight was also examined for the same 30 families. Port-Orford-cedar seedlings were inoculated by exposure to natural inoculum at a field site or by aerosol application of macerated mycelium of S. thujina cultures to seedling foliage in a greenhouse study and evaluated for Stigmina blight symptoms after 12 months. Stigmina symptoms were also compared in a naturally infected POC common garden plantation representing a range-wide collection of Port- Orford-cedar. Differences in symptom severity between families were found for all three assays. However, with one exception, no correlation was found between resistance to infection by Stigmina thujina and resistance to P. lateralis. Seedstock collected from watersheds that differed in elevation, precipitation, latitude and longitude were found to have significant variation in levels of disease severity caused by S. thujina. Families from watersheds nearest to the coast, from more northern latitudes and lower elevations showed lower levels of S. thujina disease symptoms. POC seedlings from parent trees located in watersheds in the southernmost, most inland provenances, higher elevations and lower mean annual precipitation (mm) had higher Stigmina disease ratings. In order to identify the species of Seiridium associated with cypress canker in Oregon, eight isolates of Seiridium were collected from three host species in various plantations in southwest Oregon. The diagnostic features of the Seiridium isolates were morphologically most similar to those described for S. cardinale. However, phylogenetic analysis based on ß-tubulin and histone gene sequences grouped the Oregon isolates in a separate clade from S. cardinale isolates. The Oregon Seiridium isolates occurred in a sister relationship with S. unicorne isolates from Portugal. The lack of agreement between the morphological characteristics of the Oregon Port-Orford cedar isolates and the phylogenetic analysis suggests that there may be greater variation in the morphological characters of S. unicorne than previously recognized, or that the Seiridium species from Oregon represents a hitherto unrecognized species. Previously reported analyses of pathogenic Seiridium species did not include isolates from North America, which appear more variable than isolates from Europe, New Zealand and Africa. The results of this study indicate that further analyses of Seiridium isolates from North America, including additional putative specimens from C. macrocarpa are needed to resolve this question. A number of challenges affected the success of inoculation testing procedures in this study. These included seasonal differences and variation in seedling diameter among inoculation groups. The results of this study provide a limited understanding of variation in susceptibility of Port-Orford-cedar families to natural populations of Seiridium due to the constraint of using a single Seiridium isolate, and should be interpreted accordingly. Despite these limitations, this study presents evidence for heritable variability in susceptibility within POC families to both cypress canker and Stigmina foliage blight, and suggests that there is high potential for improvement by selective breeding. The methods described in this thesis should be useful for future testing. Variation in susceptibility to these diseases should be considered in evaluating Phytophthora root disease resistance breeding efforts.