The timing and asymmetry of plant–pathogen–insect interactions

Insects and pathogens frequently exploit the same host plant and can potentially impact each other's performance. However, studies on plant–pathogen–insect interactions have mainly focused on a fixed temporal setting or on a single interaction partner. In this study, we assessed the impact of time of attacker arrival on the outcome and symmetry of interactions between aphids ( Tuberculatus annulatus ), powdery mildew ( Erysiphe alphitoides ), and caterpillars ( Phalera bucephala ) feeding on pedunculate oak, Quercus robur , and explored how single versus multiple attackers affect oak performance. We used a multifactorial greenhouse experiment in which oak seedlings were infected with either zero, one, two, or three attackers, with the order of attacker arrival differing among treatments. The performances of all involved organisms were monitored throughout the experiment. Overall, attackers had a weak and inconsistent impact on plant performance. Interactions between attackers, when present, were asymmetric. For example, aphids performed worse, but powdery mildew performed better, when co-occurring. Order of arrival strongly affected the outcome of interactions, and early attackers modified the strength and direction of interactions between later-arriving attackers. Our study shows that interactions between plant attackers can be asymmetric, time-dependent, and species specific. This is likely to shape the ecology and evolution of plant–pathogen–insect interactions.

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Appreciation of tolerance at the impact of thermal stress on photosystem ii activity in the leaves of pedunculate oak (Quercus robur L.) trees of different ecological origin

Journal of Botany ◽

10.52240/1857-2367.2021.1(22).04 ◽

2021 ◽

Vol 13 (1(22)) ◽

pp. 13-20

Author(s):

Petru Cuza ◽

Keyword(s):

Thermal Stress ◽

Photosystem Ii ◽

Quercus Robur ◽

Central Area ◽

Extreme Weather Events ◽

Pedunculate Oak ◽

Adaptation Capacity ◽

Oak Trees ◽

Photosystem Ii Activity ◽

The Impact

Extreme weather events with high temperatures and strong sunlight have increased alarmingly in the last few decades, considerable affecting plant photosynthesis. In this study, the impact of thermal stress on photosystem II activity in the leaves of pedunculate oak trees (Quercus robur L.) of different ecological origin was assessed. Four days after the thermal shock application with a temperature of 50°C during 20, 40, 60 minutes, the processes of recovery on photosystem II activity in the leaves of the oak trees in the investigated provenances took place with different speed and fullness. The recovery of the functional state of photosystem II in the leaves of the trees showed that in the environmental conditions of the ,,Plaiul Fagului” reservation territory an advanced thermotolerance to the thermal stress action was specifi c for the origin from the north of the country (Edinet). The leaves of the trees of local and southern origin showed a low resistance to the thermal stress action. The advanced adaptation capacity, the high growth rate of the trees from the northern provenance suggest that the acorn harvested from the oaks of northern origin can be used for the works of extension of the afforestation areas in the central area of the Republic of Moldova.

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Tree testing and estimation of heritability using the pedunculate oak Quercus robur L. seed orchard in the Krotoszyn Forest District

Forest Research Papers ◽

10.2478/frp-2018-0031 ◽

2018 ◽

Vol 79 (4) ◽

pp. 309-315

Author(s):

Władysław Barzdajn ◽

Maciej Bruder

Keyword(s):

Powdery Mildew ◽

Quercus Robur ◽

Tree Height ◽

Multiple Shoots ◽

Seed Orchard ◽

Progeny Testing ◽

Pedunculate Oak ◽

Randomized Design ◽

Forest District ◽

Index Family

Abstract In this paper, we present the results and analyse of tree height measurements, phenological observations (bud flushing), oak powdery mildew symptoms and multiple shoots of pedunculate oaks Quercus robur L. at the age of 12 years. The examined oaks belonged to 29 open pollination families. Family as well as individual heritability scored very highly for their respective indices. The calculated indices were 0.83 for tree height, 0.98 for flushing of buds, 0.53 for oak powdery mildew symptoms and 0.58 for the multi-stem index. Family seed orchards established using a completely randomized design are not a reliable substitute for progeny testing, because of the commonly small number of collected families.

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Relationships between the Pathogen Erysiphe alphitoides, the Phytophagous Mite Schizotetranychus garmani (Acari: Tetranychidae) and the Predatory Mite Euseius finlandicus (Acari: Phytoseiidae) in Oak

Insects ◽

10.3390/insects12110981 ◽

2021 ◽

Vol 12 (11) ◽

pp. 981

Author(s):

Slobodan Milanović ◽

Katarina Mladenović ◽

Bojan Stojnić ◽

Alejandro Solla ◽

Ivan Milenković ◽

...

Keyword(s):

Body Size ◽

Powdery Mildew ◽

Population Density ◽

The Body ◽

Pedunculate Oak ◽

Adult Size ◽

Phytophagous Mite ◽

Euseius Finlandicus ◽

Erysiphe Alphitoides ◽

The Impact

Food webs on forest trees include plant pathogens, arthropods, and their natural enemies. To increase the understanding of the impact of a plant pathogen on herbivore-natural enemy interactions, we studied the powdery mildew fungus Erysiphe alphitoides, the phytophagous mite Schizotetranychus garmani, and the predatory and mycophagous mite Euseius finlandicus in pedunculate oak (Quercus robur) leaves. In June, July and August of 2016, we assessed the severity of powdery mildew, mite population density and adult female mite size in 30 trees in three forests near Belgrade, Serbia. In August, the infection severity of E. alphitoides related positively to the population density of S. garmani and negatively to the body size of S. garmani females. Throughout the vegetative season, the infection severity of E. alphitoides related positively to the population density of E. finlandicus but not to its body size. The effect of E. alphitoides on the population density and adult size of S. garmani was not mediated by the population density of E. finlandicus, and vice versa. Interactions were consistent in all forests and varied with the summer month. Our findings indicate that E. alphitoides can influence the average body size and population densities of prey and predatory mites studied, irrespective of predator-prey relationships.

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The most frequent powdery mildews on forest woody species and their impact

Glasnik Sumarskog fakulteta ◽

10.2298/gsf0591009k ◽

2005 ◽

pp. 9-29 ◽

Cited By ~ 5

Author(s):

Dragan Karadzic ◽

Tanja Milijasevic

Keyword(s):

Powdery Mildew ◽

Gypsy Moth ◽

Natural Regeneration ◽

Quercus Robur ◽

Woody Species ◽

Pedunculate Oak ◽

Forest Trees ◽

Fungus Species ◽

Powdery Mildews ◽

Oak Trees

The most frequent fungus species known as powdery mildews, causing the diseases of forest trees, were studied. Among forest woody species, oaks are especially susceptible to powdery mildew attack, and among them pedunculate oak (Quercus robur L) is highly endangered. This paper reports 49 species of powdery mildews. However, Microsphaera alphitoides has the greatest significance in forest economy, causing the decline of seedlings in nurseries and also aggravating the natural regeneration of pedunculate oak. This fungus, together with gypsy moth and honey fungus (Armillaria mellea) participates in the dying of old oak trees. Powdery mildews can be successfully controlled by fungicides, and sulphur fungicides Karatan and Rubigan are especially effective.

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Effects of oak powdery mildew (Erysiphe alphitoides [Griffon and Maubl.] U. Braun and S. Takam.) on photosynthesis of pedunculate oak (Quercus robur L.)

Zbornik Matice srpske za prirodne nauke ◽

10.2298/zmspn1936043v ◽

2019 ◽

pp. 43-56

Author(s):

Erna Vastag ◽

Rudolf Kastori ◽

Sasa Orlovic ◽

Mirjana Bojovic ◽

Lazar Kesic ◽

...

Keyword(s):

Gas Exchange ◽

Powdery Mildew ◽

Chlorophyll A ◽

Chlorophyll A Fluorescence ◽

Quercus Robur ◽

Pedunculate Oak ◽

Fast Kinetics ◽

Fluorescence Parameters ◽

Significant Difference ◽

Erysiphe Alphitoides

The aim of the present study was to evaluate the effect of one of the most important foliar diseases, powdery mildew, on the leaf physiological traits of Quercus robur L. using chlorophyll a fluorescence parameters in combination with parameters of leaf gas exchange. For this purpose, greenhouse semi-controlled experiment was conducted with 25 one-year-old seedlings kept in optimal conditions, and the same number of seedlings infected with the mentioned pathogen. Measurements were carried out when the coverage of epiphytic micelia visually reached more than 75% of the surface of leaves in the infected seedlings. The results of gas exchange measurement showed that Erysiphe alphitoides (Griffon and Maubl.) U. Braun and S. Takam caused a significant reduction of net photosynthesis (A) and a significant increase in substomatal CO2 concentration (Ci). Furthermore, considering the fast kinetics of chlorophyll a fluorescence, all of the observes parameters were significantly affected by oak powdery mildew. On the other hand, pulse amplitude modulated fluorescence parameters were mildly affected, with only minimal (Fo?) and maximal (Fm?) fluorescence of dark adopted leaves showing significant difference. This study presented the possibility of usage and the effectiveness of chlorophyll a fluorescence parameters in detection the severe stress conditions, on the example of leaves infected with oak powdery mildew over 75%. Some additional studies should be conducted in the future to determine the possibility of usage and the effectiveness of the observed fluorescence parameters of fast kinetics in detection of mild and early stress.

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Physiological responses of Pedunculate oak (Quercus robur L.) to Corythucha arcuata (Say, 1832) attack

Archives of Biological Sciences ◽

10.2298/abs180927058n ◽

2019 ◽

Vol 71 (1) ◽

pp. 167-176 ◽

Cited By ~ 2

Author(s):

Natasa Nikolic ◽

Andrej Pilipovic ◽

Milan Drekic ◽

Danijela Kojic ◽

Leopold Poljakovic-Pajnik ◽

...

Keyword(s):

Antioxidant Enzymes ◽

Quercus Robur ◽

Physiological Responses ◽

Mineral Nutrient ◽

Distribution Area ◽

Nutrient Concentrations ◽

Plant Responses ◽

Pedunculate Oak ◽

Lace Bug ◽

The Impact

The spread and occurrence of the oak lace bug Corythucha arcuata out of its natural distribution area across European and Asian countries has been reported during the past decades. The ecological and economic significance of oak stands and the vulnerability of plants to various abiotic and/or biotic factors requires in-depth knowledge of plant-pest interaction. The present study examined the influence of C. arcuata feeding on the photosynthetic characteristics and gas-exchange parameters, mineral nutrient concentrations and defense mechanisms (the activities of some antioxidant enzymes) of leaves of pedunculate oak. The rate of photosynthesis, transpiration and stomatal conductance were lowered by 58.84, 21.66 and 35.71%, respectively, in comparison to non-infested plants. The concentrations of photosynthetic pigments and activities of antioxidant enzymes, catalase and ascorbate peroxidase, were affected by the presence of C. arcuata. To our knowledge this is the first paper providing a report on the physiological responses of Quercus robur plants exposed to C. arcuata infestation. Understanding the impact of pests, such as the invasive species C. arcuata on physiological processes and vitality of young plants and plant responses, could provide a foundation for efficient preservation of oak forests endangered by the oak lace bug.

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The impact of statin therapy after surgical or endovascular treatment of cerebral aneurysms

Journal of Neurosurgery ◽

10.3171/2019.3.jns183500 ◽

2020 ◽

Vol 133 (1) ◽

pp. 182-189

Author(s):

Tae-Jin Song ◽

Seung-Hun Oh ◽

Jinkwon Kim

Keyword(s):

Statin Therapy ◽

Coil Embolization ◽

Primary Outcome ◽

Cox Regression ◽

Cerebral Aneurysms ◽

Time Dependent ◽

Lipid Lowering ◽

Surgical Clipping ◽

The Impact

OBJECTIVECerebral aneurysms represent the most common cause of spontaneous subarachnoid hemorrhage. Statins are lipid-lowering agents that may expert multiple pleiotropic vascular protective effects. The authors hypothesized that statin therapy after coil embolization or surgical clipping of cerebral aneurysms might improve clinical outcomes.METHODSThis was a retrospective cohort study using the National Health Insurance Service–National Sample Cohort Database in Korea. Patients who underwent coil embolization or surgical clipping for cerebral aneurysm between 2002 and 2013 were included. Based on prescription claims, the authors calculated the proportion of days covered (PDC) by statins during follow-up as a marker of statin therapy. The primary outcome was a composite of the development of stroke, myocardial infarction, and all-cause death. Multivariate time-dependent Cox regression analyses were performed.RESULTSA total of 1381 patients who underwent coil embolization (n = 542) or surgical clipping (n = 839) of cerebral aneurysms were included in this study. During the mean (± SD) follow-up period of 3.83 ± 3.35 years, 335 (24.3%) patients experienced the primary outcome. Adjustments were performed for sex, age (as a continuous variable), treatment modality, aneurysm rupture status (ruptured or unruptured aneurysm), hypertension, diabetes mellitus, household income level, and prior history of ischemic stroke or intracerebral hemorrhage as time-independent variables and statin therapy during follow-up as a time-dependent variable. Consistent statin therapy (PDC > 80%) was significantly associated with a lower risk of the primary outcome (adjusted hazard ratio 0.34, 95% CI 0.14–0.85).CONCLUSIONSConsistent statin therapy was significantly associated with better prognosis after coil embolization or surgical clipping of cerebral aneurysms.

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Growth and management of mixed Pinus sylvestris - Quercus robur stands in Flanders, Belgium

Silva Gandavensis ◽

10.21825/sg.v58i0.880 ◽

1993 ◽

Vol 58 ◽

Cited By ~ 1

Author(s):

D. Maddelein ◽

J. Neirynck ◽

G. Sioen

Keyword(s):

Pinus Sylvestris ◽

Natural Regeneration ◽

Quercus Robur ◽

Good Growth ◽

Pedunculate Oak ◽

Selection System ◽

Management Options ◽

Stand Management ◽

Pine Stands

Mature Scots pine (Pinus sylvestris L.) stands are dominating large parts of the Flemish forest area. Broadleaved species regenerate spontaneously under this pine canopy. This study studied the growth and development of two planted pine stands with an older natural regeneration, dominated by pedunculate oak (Quercus robur L.), and discussed management options for similar stands. The results indicated a rather good growth of the stands, with current annual increments of 5 m3.ha-1.yr-1. The pine overstorey is growing into valuable sawwood dimensions, while the broadleaved understorey slowly grows into the upperstorey. The quality of the regeneration is moderate but can be improved by silvicultural measurements (pruning, early selection). In both stands, an interesting (timber production, nature conservation) admixture of secondary tree species is present in the regeneration. Stand management is evolving from the classical clearcut system towards a combination of a type of selection and group selection system.

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COVID-19: Time-Dependent Effective Reproduction Number and Sub-notification Effect Estimation Modeling (Preprint)

10.2196/preprints.23997 ◽

2020 ◽

Author(s):

Eduardo Atem De Carvalho ◽

Rogerio Atem De Carvalho

Keyword(s):

New York ◽

Reproduction Number ◽

Moving Average ◽

Real Data ◽

Time Dependent ◽

Initial Value ◽

Health Authorities ◽

Reproduction Numbers ◽

Effect Estimation ◽

The Impact

BACKGROUND Since the beginning of the COVID-19 pandemic, researchers and health authorities have sought to identify the different parameters that govern their infection and death cycles, in order to be able to make better decisions. In particular, a series of reproduction number estimation models have been presented, with different practical results. OBJECTIVE This article aims to present an effective and efficient model for estimating the Reproduction Number and to discuss the impacts of sub-notification on these calculations. METHODS The concept of Moving Average Method with Initial value (MAMI) is used, as well as a model for Rt, the Reproduction Number, is derived from experimental data. The models are applied to real data and their performance is presented. RESULTS Analyses on Rt and sub-notification effects for Germany, Italy, Sweden, United Kingdom, South Korea, and the State of New York are presented to show the performance of the methods here introduced. CONCLUSIONS We show that, with relatively simple mathematical tools, it is possible to obtain reliable values for time-dependent, incubation period-independent Reproduction Numbers (Rt). We also demonstrate that the impact of sub-notification is relatively low, after the initial phase of the epidemic cycle has passed.

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Impacts of separate rejection water treatment on the overall plant performance

Water Science & Technology ◽

10.2166/wst.2003.0240 ◽

2003 ◽

Vol 48 (4) ◽

pp. 139-146 ◽

Cited By ~ 17

Author(s):

B. Wett ◽

J. Alex

Keyword(s):

Water Treatment ◽

Treatment Plant ◽

Operating Experience ◽

Plant Performance ◽

High Tech ◽

State Variables ◽

Total N ◽

Unit Process ◽

Innovative Tool ◽

The Impact

A separate rejection water treatment appears as a high-tech unit process which might be recommendable only for specific cases of an upgrading of an existing wastewater treatment plant. It is not the issue of this paper to consider a specific separate treatment process itself but to investigate the influence of such a process on the overall plant performance. A plant-wide model has been applied as an innovative tool to evaluate effects of the implemented sidestream strategy on the mainstream treatment. The model has been developed in the SIMBA environment and combines acknowledged mathematical descriptions of the activated sludge process (ASM1) and the anaerobic mesophilic digestion (Siegrist model). The model's calibration and validation was based on data from 5 years of operating experience of a full-scale rejection water treatment. The impact on the total N-elimination efficiency is demonstrated by detailed nitrogen mass flow schemes including the interactions between the wastewater and the sludge lane. Additionally limiting conditions due to dynamic N-return loads are displayed by the model's state variables.

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