scholarly journals Historic declines in growth portend trembling aspen death during a contemporary leaf miner outbreak in Alaska

Ecosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
Author(s):  
Melissa A. Boyd ◽  
Logan T. Berner ◽  
Adrianna C. Foster ◽  
Scott J. Goetz ◽  
Brendan M. Rogers ◽  
...  
Keyword(s):  
PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250078
Author(s):  
Roger W. Ruess ◽  
Loretta M. Winton ◽  
Gerard C. Adams

Over the past several decades, growth declines and mortality of trembling aspen throughout western Canada and the United States have been linked to drought, often interacting with outbreaks of insects and fungal pathogens, resulting in a “sudden aspen decline” throughout much of aspen’s range. In 2015, we noticed an aggressive fungal canker causing widespread mortality of aspen throughout interior Alaska and initiated a study to quantify potential drivers for the incidence, virulence, and distribution of the disease. Stand-level infection rates among 88 study sites distributed across 6 Alaska ecoregions ranged from <1 to 69%, with the proportion of trees with canker that were dead averaging 70% across all sites. The disease is most prevalent north of the Alaska Range within the Tanana Kuskokwim ecoregion. Modeling canker probability as a function of ecoregion, stand structure, landscape position, and climate revealed that smaller-diameter trees in older stands with greater aspen basal area have the highest canker incidence and mortality, while younger trees in younger stands appear virtually immune to the disease. Sites with higher summer vapor pressure deficits had significantly higher levels of canker infection and mortality. We believe the combined effects of this novel fungal canker pathogen, drought, and the persistent aspen leaf miner outbreak are triggering feedbacks between carbon starvation and hydraulic failure that are ultimately driving widespread mortality. Warmer early-season temperatures and prolonged late summer drought are leading to larger and more severe wildfires throughout interior Alaska that are favoring a shift from black spruce to forests dominated by Alaska paper birch and aspen. Widespread aspen mortality fostered by this rapidly spreading pathogen has significant implications for successional dynamics, ecosystem function, and feedbacks to disturbance regimes, particularly on sites too dry for Alaska paper birch.


2019 ◽  
Vol 53 (5) ◽  
pp. 375-384
Author(s):  
M. Drohvalenko ◽  
A. Mykhailenko ◽  
M. Rekrotchuk ◽  
L. Shpak ◽  
V. Shuba ◽  
...  

Abstract A part of the COI mitochondrial barcoding gene was sequenced from seven species of different taxonomical groups: Ambystoma mexicanum (Amphibia, Ambystomatidae), Darevskia lindholmi, Lacerta agilis exigua (Reptilia, Lacertidae), Erinaceus roumanicus (Mammalia, Erinaceidae), Macrobiotus sp. 1 and 2 (Eutardigrada, Macrobiotidae) and Cameraria ohridella (Insecta, Gracillariidae). The sequences were compared with available sequences from databases and positioned on phylogenetic trees when the taxa had not yet been sequenced. The presence of Mexican axolotls in herpetoculture in Ukraine was confirmed. The partial COI genes of the Crimean rock lizard and an eastern sub-species of the sand lizard were sequenced. We demonstrated the presence of two tardigrade mitochondrial lineages of the Macrobiotus hufelandi group in the same sample from the Zeya Natural Reserve in the Far East: one was nearly identical to the Italian M. macrocalix, and the other one is similar to M. persimilis and M. vladimiri. We also confirmed the presence of the invasive haplotype “A” of the horse chestnut leaf miner in Ukraine, in line with the hypothesized route of invasion from Central Europe.


2007 ◽  
Vol 1 (2) ◽  
pp. 145-146 ◽  
Author(s):  
R. S. Malhotra ◽  
M. EL Bouhssini ◽  
A. Joubi
Keyword(s):  

1995 ◽  
Vol 30 (2) ◽  
pp. 243-246 ◽  
Author(s):  
Heather Culbert ◽  
Robert France

Abstract In urban centres, leaves are customarily gathered and temporarily stored in large roadside piles prior to their transport to disposal sites. To simulate the release of total phosphorus to urban runoff, birch and trembling aspen leaves were leached with distilled water in laboratory flasks. There was no difference in rate of total phosphorus release between oven-dried and non-dried leaves. An empirical equation developed from these data and knowledge of the litterfall rates for southern Canada indicated that leaves yielded from 11 to 45 mg TP m−2 of forested watershed. This amount represents up to 5% of the total export of total phosphorus from urban catchments and has the potential to exacerbate eutrophication of municipal waters if leaf pickup is not promptly enforced.


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Alime Bayindir Erol ◽  
Oktay Erdoğan ◽  
İsmail Karaca

Abstract Background In this study, commercial bioinsecticides including entomopathogenic fungi, Beauveria bassiana, Metarhizium anisopliae, and Verticillium lecanii, and Spinetoram active ingredient insecticide were evaluated against the tomato leaf miner, Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) larvae. Main body The active ingredients were prepared at the recommended concentrations under laboratory conditions and applied to the 2nd instar larvae of T. absoluta by spraying with a hand sprayer. On the 1st, 3rd, 5th, and 7th days of the application, evaluations were made by counting survived individuals. The findings showed that the highest mortality rates were detected in the case of Spinetoram with 56, 60, 88, and 100% on all counting days of the experiments, respectively. The highest mortality rate among bioinsecticides was recorded for M. anisopliae, with 87% mortality on the 7th day of application. Short conclusion As a result, Spinetoram was found the most effective insecticide when applied to T. absoluta, followed by M. anisopliae.


Agronomy ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 57
Author(s):  
Nesrine Chrigui ◽  
Duygu Sari ◽  
Hatice Sari ◽  
Tuba Eker ◽  
Mehmet Fatih Cengiz ◽  
...  

The chickpea leafminer, Liriomyza cicerina (Rondani), is one of the most destructive insect pests of cultivated chickpea (Cicer arietinum L.) in the Mediterranean region under field conditions. For sustainable and environmentally friendly chickpea production, efforts have been devoted to managing the leafminer via decreasing the use of insecticides. Breeding of new resistant varieties is not only an efficient and practical approach, but also cost-effective and environmentally sensitive. To improve resistant varieties, breeders need reliable biochemical selection criteria that can be used in breeding programs. The first objective was to investigate the possible introgression of resistance to the leafminer from C. reticulatum Ladiz. (resistant) to C. arietinum (susceptible), then, to estimate inheritance of resistance to the leafminer for efficient breeding strategies, and finally, to study organic acid contents as selection criteria. Recombinant inbred lines (RILs) and their parents were evaluated using a visual scale of 1–9 (1 = free from leafminer damage and 9 = mines in more than 91% of the leaflets and defoliation greater than 31%) in the field under natural infestation conditions after the susceptible parent and check had scores of >7 on the visual scale. Superior RILs were found for resistance to the leafminer, and agro-morphological traits indicating that introgression of resistance to leaf miner from C. reticulatum to C. arietinum could be possible using interspecific crosses. The inheritance pattern of resistance to the leafminer in RILs was shown to be quantitative. Organic acids, including oxalic, malic, quinic, tartaric, citric and succinic acids in RILs grown in the field under insect epidemic conditions and in the greenhouse under non-infested conditions were detected by using high performance liquid chromatography (HPLC). In general, organic acids were found to be higher in resistant RILs than susceptible RILs. Path and correlation coefficients showed that succinic acid exhibited the highest direct effects on resistance to the leafminer. Multivariate analyses, including path, correlation and factor analyses suggested that a high level of succinic acid could be used as a potential biochemical selection criterion for resistance to leafminer in chickpea. Resistant RILs with a high seed yield resembling kabuli chickpea can be grown directly in the target environments under leaf miner infestation conditions.


Life ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 413
Author(s):  
Kevin Piato ◽  
Cristian Subía ◽  
Jimmy Pico ◽  
Darío Calderón ◽  
Lindsey Norgrove ◽  
...  

Coffee agroforestry systems could reconcile agricultural and environmental objectives. While pests and diseases can reduce yield, their interactions with shade and nutrition have been rarely researched, and are particularly lacking in perennial systems. We hypothesized that intermediate shade levels could reduce coffee pests while excess shade could favor fungal diseases. We hypothesized that organic rather than mineral fertilization would better synchronize with nutrient uptake and higher nutrient inputs would be associated with reduced pest and disease damage due to higher plant vigor, yet effects would be less obvious in shaded plots as coffee growth would be light-limited. Using three-year-old trees of Coffea canephora var. Robusta (robusta coffee) in the Ecuadorian Amazon, we compared a full-sun system with four shading methods creating different shade levels: (1) Myroxylon balsamum; (2) Inga edulis; (3) Erythrina spp.; or, (4) Erythrina spp. plus Myroxylon balsamum. Conventional farming at either (1) moderate or (2) intensified input and organic farming at (3) low or (4) intensified input were compared in a split-plot design with shade as the main plot factor and farming practice as the sub-plot factor. The infestation of the following pests and disease incidences were evaluated monthly during the dry season: brown twig beetle (Xylosandrus morigerus), coffee leaf miner (Leucoptera coffeella), coffee berry borer (Hypothenemus hampei), anthracnose disease (Colletotrichum spp.), thread blight (Pellicularia koleroga), and cercospora leaf spot (Cercospora coffeicola). Coffee berry borer and brown twig beetle infestation were both reduced by 7% in intensified organic treatments compared to intensified conventional treatments. Colonization of coffee berry borer holes in coffee berries by the entomopathogenic fungus Beauveria bassiana was also assessed. Brown twig beetle infestation was significantly higher under full sun than under Inga edulis, yet no other shade effects were detected. We demonstrate for the first time how intensified input use might promote pest populations and thus ultimately lead to robusta coffee yield losses.


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.


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