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.

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.

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

Detection of root disease in coastal Douglas-fir stands using large scale 70-mm aerial photography

1984 ◽  
Vol 14 (4) ◽  
pp. 523-527 ◽  
Author(s):  
G. W. Wallis ◽  
Y. J. Lee
Keyword(s):  
Aerial Photography ◽  
Large Scale ◽  
Douglas Fir ◽  
Root Disease ◽  
Aerial Photographs ◽  
Stand Age ◽  
Adequate Information ◽  
Disease Occurrence ◽  
Mature Stands

Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands 15, 40, and 100 years of age containing root disease openings of various sizes were photographed using 70-mm Aerochrome color and color-infrared film at scales of 1:1 500 to 1:15 000. Success in detecting disease centers varied with scale relative to stand age and disease symptomatology. Scales of 1:6 000 provided adequate information for young stands 15–20 years of age whereas scales of up to 1:15 000 proved satisfactory for locating most centers in 100-year-old stands. The large variation in symptomatology among stands in the midage class made accurate assessment of disease occurrence difficult at all scales used. Measurement of area within most disease centers in a stand using aerial photographs is probably feasible only in mature stands. Color photographs were superior to color-infrared for detecting early foliage discoloration; the reverse was true when characterization of ground features and downed trees was desired.

Symptom expression in conifers infected with Armillaria ostoyae and Heterobasidion annosum

2004 ◽  
Vol 34 (6) ◽  
pp. 1210-1219 ◽  
Author(s):  
Daniel W Omdal ◽  
Charles G Shaw, III ◽  
William R Jacobi
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Lateral Roots ◽  
Douglas Fir ◽  
Root Disease ◽  
Heterobasidion Annosum ◽  
Armillaria Ostoyae ◽  
White Fir ◽  
Pine Trees ◽  
Old Trees

Crown symptoms and other aboveground variables were examined on 36 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco.) (40–209 years old), 46 white fir (Abies concolor (Gord. & Glend.) Lindl.) (36–165 years old), and 97 ponderosa pine (Pinus ponderosa Dougl. ex Laws.) (64–220 years old) trees in northern New Mexico and southern Colorado. Root systems of all trees were excavated to determine extent of root disease. Symptoms observed on infected trees, including reductions in height growth, changes in foliage characteristics, and crown dieback, worsened as the number of infected roots increased. Trees with aboveground symptoms had a significantly higher (p < 0.05) number of infected lateral roots than trees without symptoms. In mixed conifer stands on the Archuleta Mesa, Colo., four qualitative crown symptoms were used to accurately detect Armillaria ostoyae (Romagn.) Herink and (or) Heterobasidion annosum (Fr.) Bref. infection of Douglas-fir (21/22, or 95%) and white fir (19/28, or 68%). Similarly, 61% (48/79) of the A. ostoyae infected ponderosa pine trees on the Jemez site, N.M., were detected using the qualitative Thomson vigor rating system. Discriminate analysis, using more thorough variables and analysis, resulted in correct infection classifications of 82%, 85%, and 78% for Douglas-fir, white fir, and ponderosa pine, respectively, suggesting that aboveground variables are reasonable indicators of root disease.

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

Boron and Magnesium Fertilization of a Coastal Douglas-Fir Plantation

1993 ◽  
Vol 8 (2) ◽  
pp. 48-53 ◽  
Author(s):  
R. N. Green ◽  
R. E. Carter
Keyword(s):  
Height Growth ◽  
Douglas Fir ◽  
Boron Deficiency ◽  
Growing Seasons ◽  
Foliar Symptoms ◽  
Foliar Concentrations ◽  
A Site ◽  
Coastal British Columbia ◽  
Severe Growth

Abstract This study examines the role of boron and magnesium nutrition in the occurrence of severe growth distortion symptoms in Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) in the Skwawka River valley of south coastal British Columbia. Four fertilizer treatments including boron (2.25 kg B/ha), magnesium (42 kg Mg/ha), boron plus magnesium, and a control, were applied in conjunction with planting on a site believed to be deficient in these nutrients. After 5 growing seasons, only treatments containing boron (B and B+Mg) showed improved height growth over the control trees. The incidence of leader dieback, swollen leading shoots, and foliage distortion was significantly related to treatment with virtually no occurrence in plots treated with boron. Seedling uptake of applied boron was high, with foliar concentrations of 45 ppm found after the second growing season. Foliar B levels declined to 13-15 ppm after 5 growing seasons. No significant increase in foliar magnesium levels was detected for either of the magnesium treatments. The reduction in the incidence of leader dieback and shoot and foliar symptoms in seedlings treated with B indicate that these symptoms were the result of boron deficiencies. This is the first study to verify boron deficiency in coastal Douglas-fir through fertilizer trials. West. J. Appl. For. 8(2):48-53.

scholarly journals Root Volume and Growth of Ponderosa Pine and Douglas-Fir Seedlings: A Summary of Eight Growing Seasons

1997 ◽  
Vol 12 (3) ◽  
pp. 69-73 ◽  
Author(s):  
R. Rose ◽  
D. L. Haase ◽  
F. Kroiher ◽  
T. Sabin
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Douglas Fir ◽  
Stem Volume ◽  
Coast Range ◽  
Root Volume ◽  
Growth And Survival ◽  
Growing Seasons ◽  
Early Results

Abstract This is the final summary of two studies on the relationship between root volume and seedling growth; early results were published previously. Survival, growth, and stem volume were determined for 2+0 ponderosa pine (Pinus ponderosa) and Douglas-fir (Pseudotsuga menziesii) seedlings after 8 growing seasons. For each species, seedlings from three seedlots were assigned to one of three root-volume categories [<4.5 cm3 (RV1), 4.5-7 cm3 (RV2), and >7 cm3 (RV3) for ponderosa pine; <9 cm3 (RV1), 9-13 cm3 (RV2), and >13 cm3 (RV3) for Douglas-fir]. On a dry harsh ponderosa pine site on the eastern slopes of Mt. Hood in Oregon, where gopher and cattle damage decreased the number of seedlings, more seedlings in the highest root-volume category survived (70%) than in the smaller root-volume categories (62% and 50%). Douglas-fir on a good site in the Coast Range of Oregon showed significantly greater height and stem volume for the largest root-volume category, whereas annual shoot growth and survival did not differ. Root volume is one of several potentially useful criteria for predicting long-term growth and survival after outplanting. West. J. Appl. For. 12(3):69-73.

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.

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