Fungal lesion length and expansion rate for the root pathogen Armillaria ostoyae in Douglas-fir affecting root colonization and damage

2020 ◽  
Vol 50 (3) ◽  
pp. e12598
Author(s):  
Michael G. Cruickshank ◽  
Derek F. Sattler
Keyword(s):  
Root Colonization ◽  
Douglas Fir ◽  
Expansion Rate ◽  
Lesion Length ◽  
Root Pathogen ◽  
Armillaria Ostoyae

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.

Cylindrocarpon and Fusarium root colonization of Douglas-fir seedlings from British Columbia reforestation sites

1998 ◽  
Vol 28 (8) ◽  
pp. 1198-1206 ◽  
Author(s):  
Paige E Axelrood ◽  
William K Chapman ◽  
Keith A Seifert ◽  
David B Trotter ◽  
Gwen Shrimpton
Keyword(s):  
British Columbia ◽  
Pseudotsuga Menziesii ◽  
Root Colonization ◽  
Linear Trend ◽  
Poor Performance ◽  
Douglas Fir ◽  
Root Infection ◽  
Significant Linear Trend ◽  
Conifer Seedlings ◽  
Cylindrocarpon Destructans

Poor performance of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantations established in 1987 has occurred in southwestern British Columbia. Affected sites were planted with 1-year-old container stock that exhibited some root dieback in the nursery. A study was initiated in 1991 to assess Cylindrocarpon and Fusarium root infection in planted and naturally regenerating (natural) Douglas-fir seedlings from seven affected plantations. Percentages of seedlings harboring Cylindrocarpon spp.and percent root colonization were significantly greater for planted seedlings compared with natural seedlings. A significant linear trend in Cylindrocarpon root colonization was observed for planted seedlings with colonization levels being highest for roots closest to the remnants of the root plug and decreasing at distances greater than 10cm from that region. This trend in Cylindrocarpon colonization was not observed for natural seedlings. Cylindrocarpon destructans (Zins.) Scholten var. destructans and C.cylindroides Wollenw. var. cylindroides were the only species isolated from planted and natural conifer seedlings. For most sites, percentage of seedlings harboring Fusarium spp.and percent Fusarium root colonization were less than for Cylindrocarpon. Recovery of Fusarium spp.from seedlings and root colonization levels were not significantly different for planted and natural seedlings from all sites.

Soil disturbance and juvenile Douglas-fir growth following stump removal on moderately coarse textured soils in southwestern British Columbia: 10-year results

2019 ◽  
Vol 49 (7) ◽  
pp. 767-774
Author(s):  
Stefan Zeglen ◽  
Paul J. Courtin
Keyword(s):  
British Columbia ◽  
Tree Growth ◽  
Basal Area ◽  
Soil Disturbance ◽  
Douglas Fir ◽  
Stand Development ◽  
Site Productivity ◽  
Nutrient Analysis ◽  
Armillaria Ostoyae ◽  
Root Diseases

Mechanized treatment for root diseases such as Coniferiporia sulphurascens (Pilát) L. W. Zhou & Y. C. Dai (syn. Phellinus sulphurascens Pilát) and Armillaria ostoyae (Romagn.) Herink (syn. Armillaria solidipes Peck) is often avoided due to cost or the perception that removal of stumps creates detrimental soil disturbance or degradation that hinders site productivity. Our study tested five diseased stands that were treated by extracting stumps following harvesting and replanted with susceptible Douglas-fir. Soil disturbance surveys were conducted in treated and untreated plots, and individual planted spots were assessed and categorized for soil disturbance using existing and proposed new categories specific to disturbance caused by the stump removal. Tree measurements were taken at intervals over the first 10 years of stand development, and foliage was sampled for nutrient analysis. The percentage of total and counted disturbance was 20%–46% and 8%–11% greater, respectively, in treated versus untreated plots; however, mean tree growth in height and diameter was not statistically different between treatments and was more positive for treated plots at all sites but one. Tree nutrition and survival to age 10 was not negatively affected by stump removal. Total site productivity represented by basal area and tree volume differed widely between sites but was not significantly different between treatments.

Resistance of half-sib interior Douglas-fir families to Armillaria ostoyae in British Columbia following artificial inoculation

2010 ◽  
Vol 40 (1) ◽  
pp. 155-166 ◽  
Author(s):  
M. G. Cruickshank ◽  
B. Jaquish ◽  
A. F.L. Nemec
Keyword(s):  
British Columbia ◽  
Root System ◽  
Pseudotsuga Menziesii ◽  
Tree Breeding ◽  
Douglas Fir ◽  
Survival Analyses ◽  
Conifer Seedlings ◽  
Greenhouse Trial ◽  
Armillaria Ostoyae ◽  
The Family

The objectives of this study were to (i) develop a methodology for screening conifer seedlings for resistance to Armillaria ostoyae (Romagn.) Herink and (ii) screen a population of interior Douglas-fir ( Pseudotsuga menziesii var. glauca (Biessn.) Franco) population for resistance to A. ostoyae. Eighteen potted seedlings from each of 86 half-sib interior Douglas-fir families were challenged with inoculum in a 3-year greenhouse trial. The seed originated from four geographically distinct tree breeding zones that represent physically and biologically different environments in southeastern British Columbia. Mortality and the final percent survival of inoculated trees showed differences among the families (survival range 0%–61.1%) and breeding zones (survival range 6.6%–25.3%). Maximum heritability index (0.19) occurred at 28 months. Survival analyses revealed that most of the differences in survival could be explained by the zone from which the family originated. The less susceptible seedlings originated from the drier and warmer zones and limited the spread of the fungus in the root system. Moderate levels of family variation in resistance to A. ostoyae and low-moderate heritability suggest that, in interior Douglas-fir, gains in resistance can be achieved through breeding.

Diversity of ectomycorrhizae on experimentally planted Douglas-fir seedlings in variable retention forestry sites on southern Vancouver Island

2004 ◽  
Vol 82 (11) ◽  
pp. 1671-1681 ◽  
Author(s):  
R A Outerbridge ◽  
J A Trofymow
Keyword(s):  
Root Colonization ◽  
Distance Effect ◽  
Vancouver Island ◽  
Douglas Fir ◽  
Stand Age ◽  
Mature Trees ◽  
Old Growth ◽  
Variable Retention ◽  
Second Growth ◽  
Retention Forestry

Studies were done on Vancouver Island of ectomycorrhizal (EM) communities at four distances (5–45 m) from isolated forest patches in three second-growth (SG) and three old-growth (OG) Douglas-fir sites subject to variable retention harvesting. We tested the hypothesis that retention of mature trees enhances colonization and diversity of EM fungi on seedlings planted in adjacent areas. In total 41 EM morphotypes were described, with mean diversity of 3.47 morphotypes and root colonization of 62% per seedling. Overall, root colonization declined with distance (72% at 5 m vs. 52% at 45 m), as did EM diversity (4.7 at 5 m vs. 2.9 at 45 m). For individual sites, the distance effect was significant for root colonization at four sites and for EM diversity at three to four sites. This suggests that variable retention is important for the recovery of ectomycorrhizal biota in harvested sites. Seedling root colonization was significantly lower in SG sites than in OG sites. Though EM diversity did not differ with stand age, OG sites had potentially more total (34) and unique (14) EM morphotypes than did SG sites (total 27, unique 7). Differences with stand age might be related to the relative abilities of EM fungi to disperse to regenerating second-growth forests.Key words: variable retention silviculture, ectomycorrhizae ecology, Douglas-fir seedlings, old growth, second-growth forests.

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.

Resistance and tolerance of Douglas‐fir seedlings to inoculation with the fungal root pathogen Coniferiporia sulphurascens

2020 ◽  
Vol 50 (6) ◽  
Author(s):  
Mike G. Cruickshank ◽  
Rona N. Sturrock ◽  
Kevin W. Pellow ◽  
Isabel Leal
Keyword(s):  
Douglas Fir ◽  
Root Pathogen

scholarly journals Influence of Temperature and Time of Year on Colonization of Bermudagrass Roots by Ophiosphaerella herpotricha

Plant Disease ◽  
2006 ◽  
Vol 90 (10) ◽  
pp. 1326-1330 ◽  
Author(s):  
N. R. Walker ◽  
T. K. Mitchell ◽  
A. N. Morton ◽  
S. M. Marek
Keyword(s):  
Root Colonization ◽  
Lesion Length ◽  
Post Inoculation ◽  
Influence Of Temperature ◽  
Wide Range ◽  
Influence Of Temperature On ◽  
Soil Temperatures ◽  
Ophiosphaerella Herpotricha ◽  
Time Of Year ◽  
Field Plots

The influence of temperature on the infection of bermudagrass seedlings by Ophiosphaerella herpotricha and colonization of plants in the field was investigated. Bermudagrass seedlings (cv. Jackpot) inoculated with O. herpotricha exhibited dark lesions after 8 days. Root lesion length was greatest at 17°C and was similar for all temperatures examined below 21°C. Seedlings grown at 25 or 30°C had small lesions that remained similar in size when evaluated at 8 and 10 days post inoculation. Colonization of bermudagrass roots from field plots were examined in July, October, and November of 2003 and 2004. In 2003, no differences between sampling dates were observed for plants sampled from the edge of the spring patch in 5.4-cm increments to a total distance of 21.6 cm. In 2004, July and October samples were similar; however, an increase in root colonization was found between the October and November samplings. These studies suggest that infection and colonization of bermudagrass roots by O. herpotricha occurs over a wide range of cool soil temperatures, occurs in the spring, and can be variable in the autumn.

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