Corky root disease of Douglas-fir seedlings: pathogenicity of the nematode Xiphinemabakeri alone and in combination with the fungus Cylindrocarpondestructans

1977 ◽  
Vol 7 (1) ◽  
pp. 41-46 ◽  
Author(s):  
Jack R. Sutherland
Keyword(s):  
Synergistic Effects ◽  
Douglas Fir ◽  
Root Disease ◽  
Nematode Population ◽  
Disease Symptoms ◽  
Corky Root ◽  
Growth Room

Growth-room studies were made to determine both, alone and combined, the pathogenicity of the nematode Xiphinemabakeri Williams and the fungus Cylindrocarpondestructans (Zinnsm.) Scholten to Douglas-fir [Pseudotsugamenziesii (Mirb.) Franco] seedlings. Inoculations with 20, 40, and 60 X. bakeri nematodes per seedling resulted in nematode population increases and development of typical corky root disease symptoms. Cylindrocarpondestructans was not pathogenic to seedlings; no consistent synergistic effects were detected when inoculations were made with the nematode and fungus together. It was concluded that X. bakeri is the 'primary' pathogen in corky root etiology.

Corky Root Disease of Douglas-fir: Relation of Xiphinemabakeri Nematodes to Symptom Severity, and Observations on Seedling Tissue and Soil Nutrients

1973 ◽  
Vol 3 (2) ◽  
pp. 299-303 ◽  
Author(s):  
Jack R. Sutherland ◽  
L. J. Sluggett
Keyword(s):  
Lateral Roots ◽  
Nutrient Content ◽  
Douglas Fir ◽  
Root Disease ◽  
Root Volume ◽  
Disease Symptoms ◽  
Corky Root ◽  
Disease Occurrence ◽  
Different Depths ◽  
Coastal British Columbia

Four-month-old Douglas-fir Pseudotsugamenziesii Mirb. (Franco) seedlings were collected from a coastal British Columbia forest nursery, and the number of Xiphinemabakeri nematodes per cubic millimeter of root volume was related to the severity of several corky root disease symptoms. The strongest relationships existed between nematode root populations and seedling epicotyl length, and the number of first-order lateral roots over 5 mm long. Diseased and healthy seedlings were analyzed for tissue nutrients. Healthy seedlings contained significantly more nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), and chlorophyll, and significantly less calcium (Ca) than diseased plants. The nutrient content of soil samples collected at 0–4, 4–8, 8–12, and 12–16 cm depths from areas with or without diseased seedlings was determined. The N, Ca, Mg, and conductance levels of soils from the healthy seedling area were significantly greater than those from the disease-infested area, but no other pertinent differences, relating to disease occurrence, were found in the nutrient content of samples from the different depths, and no relevant disease class - sampling depth interactions were detected. Several factors, which help explain the recent increased incidence of corky root disease, are discussed.

Phenology and fungus-nematode relations of corky root disease of Douglas-fir

1971 ◽  
Vol 69 (3) ◽  
pp. 265-276 ◽  
Author(s):  
W. J. BLOOMBERG ◽  
JACK R. SUTHERLAND
Keyword(s):  
Douglas Fir ◽  
Root Disease ◽  
Corky Root

scholarly journals Differential interactions between strains ofRhizorhapis,Sphingobium,SphingopyxisorRhizorhabdusand accessions ofLactucaspp. with respect to severity of corky root disease

2014 ◽  
Vol 63 (5) ◽  
pp. 1053-1061 ◽  
Author(s):  
A. H. C. van Bruggen ◽  
O. Ochoa ◽  
I. M. Francis ◽  
R. W. Michelmore
Keyword(s):  
Root Disease ◽  
Corky Root

The vicious cycle of lettuce corky root disease: effects of farming system, nitrogen fertilizer and herbicide

2014 ◽  
Vol 388 (1-2) ◽  
pp. 119-132 ◽  
Author(s):  
Ariena H. C. van Bruggen ◽  
Isolde M. Francis ◽  
Randy Krag
Keyword(s):  
Nitrogen Fertilizer ◽  
Farming System ◽  
Root Disease ◽  
Vicious Cycle ◽  
Corky Root

scholarly journals Evaluation of Resistance to Rhabdocline Needlecast in Douglas Fir Variety Shuswap, with Quantitative Polymerase Chain Reaction

2010 ◽  
Vol 100 (4) ◽  
pp. 337-344 ◽  
Author(s):  
M. Catal ◽  
G. C. Adams ◽  
D. W. Fulbright
Keyword(s):  
Polymerase Chain Reaction ◽  
Quantitative Polymerase Chain Reaction ◽  
Douglas Fir ◽  
Chain Reaction ◽  
Disease Symptoms ◽  
Seed Sources ◽  
Release Times ◽  
Spore Release ◽  
Target Dna ◽  
Polymerase Chain

A quantitative polymerase chain reaction assay was developed that could detect DNA of Rhabdocline pseudotsugae and R. oblonga among DNA of Douglas fir needles to a limit as low as three copies of target DNA. Differential infection rates of two varieties (seed sources) of Douglas fir interplanted in a field were studied in relation to staggered bud breaks. Infection of Douglas fir var. San Isabel corresponded to ascospore release times for Rhabdocline spp., whereas infection of var. Shuswap Lake did not occur throughout the spore release period during 2 years of study, despite abundant inoculum and adequate moisture during bud break. Rhabdocline spp. DNA was never detected in Shuswap Lake and disease symptoms were not observed in any year. We provide evidence that Shuswap Lake is resistant and probably immune to Rhabdocline spp. infection and Rhabdocline needlecast under Michigan conditions.

The Synergistic Effects of Endoglucanase and Xylanase in Modifying Douglas Fir Kraft Pulp

1998 ◽  
pp. 75-87 ◽  
Author(s):  
Catherine D. Edgar ◽  
Shawn D. Mansfield ◽  
Georg M. Gübitz ◽  
John N. Saddler
Keyword(s):  
Kraft Pulp ◽  
Synergistic Effects ◽  
Douglas Fir

Pure culture synthesis of ectomycorrhizae by Thelephora terrestris and Pisolithus tinctorius on different conifer hosts

1970 ◽  
Vol 48 (3) ◽  
pp. 639-643 ◽  
Author(s):  
Donald H. Marx ◽  
W. Craig Bryan
Keyword(s):  
Plant Growth ◽  
Norway Spruce ◽  
Pure Culture ◽  
Douglas Fir ◽  
Pisolithus Tinctorius ◽  
Thelephora Terrestris ◽  
Fungal Symbiont ◽  
Growth Room ◽  
Pure Culture Synthesis

In a special plant-growth room, isolates of Thelephora terrestris produced basidiocarps and formed typical ectomycorrhizae with seedlings of bristlecone, jack, sand, lodgepole, shortleaf, slash, sugar, Austrian, longleaf, cluster, ponderosa, red, pitch, eastern white, Scots, loblolly, and Virginia pines and Douglas fir. Atypical mycorrhizae (lacking mantle) were formed on seedlings of Norway spruce and jack, Japanese red, and Himalayan pines. The formation of atypical mycorrhizae was considered a result of differences in the symbiotic–parasitic nature of the fungal symbionts on different hosts. Pisolithus tinctorius formed typical mycorrhizae with seedlings of jack, sand, Japanese red, shortleaf, slash, Austrian, longleaf, cluster, red, pitch, eastern white, Scots, loblolly, and Virginia pines. Reisolation of specific fungal symbionts from mycorrhizae of several pine hosts was successful.Mycorrhizae formed by T. terrestris were macroscopically and microscopically different from those of P. tinctorius, but mycorrhizae formed by different isolates of T. terrestris were indistinguishable from each other, regardless of host. These results suggest that the fungal symbiont determines color and morphology of ectomycorrhizae.

Management of corky root disease of tomato in participation with organic tomato growers

2009 ◽  
Vol 28 (2) ◽  
pp. 155-161 ◽  
Author(s):  
M.K. Hasna ◽  
E. Ögren ◽  
P. Persson ◽  
A. Mårtensson ◽  
B. Rämert
Keyword(s):  
Root Disease ◽  
Corky Root

scholarly journals Screening Lettuce Germplasm for New Sources of Resistance to Corky Root

2004 ◽  
Vol 129 (5) ◽  
pp. 712-716 ◽  
Author(s):  
Beiquan Mou ◽  
Carolee Bull
Keyword(s):  
Molecular Markers ◽  
Genetic Basis ◽  
Plant Introduction ◽  
Growth Chamber ◽  
Sources Of Resistance ◽  
Disease Symptoms ◽  
Corky Root ◽  
Resistant Lines ◽  
The World ◽  
Production Areas

Corky root is a major disease of lettuce (Lactuca sativa L.) observed in many production areas of the world. The pathogen Sphingomonas suberifaciens (van Bruggen et al.) Yabuuchi et al. varies with regard to virulence, and several strains have been isolated that can cause disease symptoms even on cultivars that have the only known resistance gene, cor. It is desirable to find new sources of resistance to diversify the genetic basis of the resistance and to confer resistance against isolates that are not adequately controlled by cor. More than 1000 plant introduction lines and cultivars were screened in assays conducted in the greenhouse, growth chamber, and field. Three L. serriola L. lines (PI 491239, PI 491096, and PI 491110) and a L. virosa L. line (PI 273597c) were highly resistant to corky root in all tests. Disease severity ratings in the field were correlated with the ratings in the greenhouse (r = 0.722) and in the growth chamber (r = 0.650). Significant genotype × environment interactions were observed for corky root severity. None of the four resistant lines had the two molecular markers closely linked to the cor allele. The information on disease resistance for these genotypes will be useful in future breeding work.

Sign in / Sign up

Export Citation Format

Share Document