scholarly journals Species associated with cytospora canker on Populus tremuloides

Mycotaxon ◽  
2015 ◽  
Vol 130 (3) ◽  
pp. 783-805 ◽  
Author(s):  
Jeff B. Kepley ◽  
F. Brent Reeves ◽  
William R. Jacobi ◽  
Gerard C. Adams

2011 ◽  
Vol 41 (12) ◽  
pp. 2315-2325 ◽  
Author(s):  
Suzanne Bethers Marchetti ◽  
James J. Worrall ◽  
Thomas Eager

Reports of drought-associated forest mortality have increased around the world, but the mechanisms of mortality are rarely direct in nature. Biotic agents may kill trees that could otherwise recover and can perpetuate and expand mortality after the stress is relieved. Sudden aspen decline (SAD) has caused rapid, widespread branch dieback and mortality of quaking aspen ( Populus tremuloides Michx.). We compared insects and diseases in 162 damaged and neighboring healthy plots to determine contributing factors and their ecological roles. Cytospora canker, bronze poplar borer, and aspen bark beetles were the most common agents in damaged plots and correlated with crown loss and other factors related to SAD. This was the first documented outbreak of Trypophloeus populi , an aspen bark beetle. As bark beetles and bronze poplar borer increased in damaged stands, they tended to attack trees with healthier crowns. Environmental stress may have directly affected the success of these agents by increasing host susceptibility followed by a density-dependent increase in the insects’ invasive ability. In contrast, Cytospora canker had an identical relationship to crown loss in healthy versus damaged plots, suggesting that it was not limited by inoculum but responded to host susceptibility. Most other pathogens and insects contributed little to SAD and appear to be primary or weakening agents. The biotic agents of mortality in a decline differ greatly from primary agents and play complex and varied roles in healthy versus declining stands.



1951 ◽  
Vol 29 (2) ◽  
pp. 147-157 ◽  
Author(s):  
T. C. Vanterpool ◽  
Ruth Macrae

The Canadian tuckahoe is the perennial sclerotium of Polyporus tuberaster jacq. ex Fries. It is commonly found in the parkland belt of the Canadian prairies where land supporting, virgin poplar groves, mainly Populus tremuloides Michx., is being brought under cultivation. Sporophore as many as three to a single sclerotium, appear in late June and July. Interfertility studies with single spore cultures isolated from sporophores derived from four sources in Western Canada and from one source in Italy have shown that both the Canadian fungus and the European P. tuberaster are heterothallic, have the tetrapolar type of interfertility, and are interfertile.



2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xiangfeng Tan ◽  
Mengmeng Liu ◽  
Ning Du ◽  
Janusz J. Zwiazek

Abstract Background Root hypoxia has detrimental effects on physiological processes and growth in most plants. The effects of hypoxia can be partly alleviated by ethylene. However, the tolerance mechanisms contributing to the ethylene-mediated hypoxia tolerance in plants remain poorly understood. Results In this study, we examined the effects of root hypoxia and exogenous ethylene treatments on leaf gas exchange, root hydraulic conductance, and the expression levels of several aquaporins of the plasma membrane intrinsic protein group (PIP) in trembling aspen (Populus tremuloides) seedlings. Ethylene enhanced net photosynthetic rates, transpiration rates, and root hydraulic conductance in hypoxic plants. Of the two subgroups of PIPs (PIP1 and PIP2), the protein abundance of PIP2s and the transcript abundance of PIP2;4 and PIP2;5 were higher in ethylene-treated trembling aspen roots compared with non-treated roots under hypoxia. The increases in the expression levels of these aquaporins could potentially facilitate root water transport. The enhanced root water transport by ethylene was likely responsible for the increase in leaf gas exchange of the hypoxic plants. Conclusions Exogenous ethylene enhanced root water transport and the expression levels of PIP2;4 and PIP2;5 in hypoxic roots of trembling aspen. The results suggest that ethylene facilitates the aquaporin-mediated water transport in plants exposed to root hypoxia.



1973 ◽  
Vol 51 (2) ◽  
pp. 498-500 ◽  
Author(s):  
Donald M. Knutson

Bacteria (Erwinia, Bacillus) were consistently isolated from all samples of aspen sapwood and heartwood. In wetwood zones (water-soaked xylem tissue) or discolored heartwood, large populations often occur. No organisms unique to wetwood were isolated. Wetwood probably is formed by nonmicrobial means and, once formed, merely supports large populations of indigenous bacteria.



2017 ◽  
Vol 38 (4) ◽  
pp. 630-640 ◽  
Author(s):  
Burke T Greer ◽  
Christopher Still ◽  
Grace L Cullinan ◽  
J Renée Brooks ◽  
Frederick C Meinzer


1999 ◽  
Vol 29 (7) ◽  
pp. 852-858 ◽  
Author(s):  
G J Harper ◽  
P G Comeau ◽  
W Hintz ◽  
R E Wall ◽  
R Prasad ◽  
...  

A national research program was established to test the field efficacy of the native fungal pathogen Chondrostereum purpureum (Pers. ex Fr.) Pouzar) for control of hardwood vegetation. During 1995, two fungal isolates were applied as a biocontrol agent to the cut stumps of Populus tremuloides Michx. (trembling aspen) and Alnus viridis ssp. sinuata (Regel) Á. Löve & D. Löve (Sitka alder). Treatments consisted of two formulations (BC, ON) in combination with two fungal isolates (2139, JAM6), blank formulations, cutting only, triclopyr herbicide application, and an uncut control. Analysis of Sitka alder clump mortality indicated isolates JAM6 and 2139 in combination with the BC formulation caused clump mortality of 90 and 88%, respectively. The blank formulation treatments caused the lowest clump mortality and appeared to promote sprouting and growth of Sitka alder when compared with cutting alone. At the aspen installation, the BC formulation with isolate 2139 was found to be the most effective fungal treatment resulting in 84% aspen stem mortality. The results from both installations suggest that C. purpureum efficacy appears to be dependent on the virulence of the isolate and the formulation.



2000 ◽  
Vol 10 (1) ◽  
pp. 34 ◽  
Author(s):  
Donald R. Zak ◽  
Kurt S. Pregitzer ◽  
Peter S. Curtis ◽  
Christoph S. Vogel ◽  
William E. Holmes ◽  
...  


2012 ◽  
Vol 90 (7) ◽  
pp. 798-807 ◽  
Author(s):  
T.W. Pettit ◽  
K.T. Wilkins

Characteristics of edges affect the behavior of species that are active in and near edges. Forest canopies may provide edge-like habitat for bats, though bat response to edge orientation has not been well examined. We sampled bat activity in quaking aspen ( Populus tremuloides Michx.) forest canopies and edges in Heber Valley, Utah, during summer 2009 using Anabat detectors. Categorization and regression tree (CART) analysis of echolocation characteristics (e.g., frequency, duration) identified two guilds based on characteristic frequency (i.e., high- and low-frequency guilds). We used linear regression to compare characteristics of canopy and edge vegetation (e.g., tree height, diameter at breast height) to bat activity levels. Activity levels of high-frequency bats did not respond differentially to edge vegetation; low-frequency bat activity seemed to respond to canopy height. Activity levels of high-frequency bats were significantly greater than low-frequency bats in both edges and canopies. We detected significantly more bat activity in forest edges than in forest canopies, indicating the importance of edges to bats in forests.



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