scholarly journals Effects of pedunculate oak tree vitality on gypsy moth preference and performance

2014 ◽  
Vol 66 (4) ◽  
pp. 1659-1672 ◽  
Author(s):  
Slobodan Milanovic ◽  
Ljubodrag Mihajlovic ◽  
Dragan Karadzic ◽  
Libor Jankovsky ◽  
Predrag Aleksic ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Gypsy Moth ◽  
Food Utilization ◽  
Pedunculate Oak ◽  
Tree Vitality ◽  
Positive Effects ◽  
Gypsy Moths ◽  
Negative Effect ◽  
And Performance ◽  
Oak Leaves

Gypsy moths and powdery mildew play a significant role in oak decline processes. However, information is lacking on the effects on the gypsy moth of impaired tree vitality caused by defoliation or parasite infection. We assessed how pedunculate oak leaves collected from vigorous, declining, and infected trees influenced gypsy moth preference and performance (growth and nutritional indices). We found a negative effect of powdery mildew-infected leaves on gypsy moth performance, while declining trees had positive effects on gypsy moth performance and preference. All examined parameters of larvae fed declining oak leaves were higher than those of larvae fed vigorous oak leaves. Increased growth on declining oak leaves was caused by both higher consumption and more efficient food utilization. The results of this research could help us to better understand multitrophic interactions in complex communities such as oak forests.

scholarly journals Preference and performance of the gypsy moth cater­pillars on sweet chestnut and some oak species

2010 ◽  
pp. 113-124 ◽  
Author(s):  
Slobodan Milanovic
Keyword(s):  
Gypsy Moth ◽  
Sweet Chestnut ◽  
Sessile Oak ◽  
Preference Index ◽  
Mixed Plantations ◽  
Study Results ◽  
Turkey Oak ◽  
And Performance ◽  
Common Oak ◽  
Oak Leaves

In the establishment of mixed plantations, it is necessary to examine previously the relations of the principal and the admixed species and the most significant pests. This paper presents the results of the study of the gypsy moth caterpillar preference and performance on sweet chestnut and four oak species. Preference index is the highest for Hungarian oak (0.83) and Turkey oak (0.77), for sessile oak it is significantly lower (0.33), and for common oak it is equal to 0. In combination with sweet chestnut, the gypsy moth second-instar caterpillars prefer Hungarian oak, i.e. Turkey oak leaves. In combination with sessile oak or common oak, the gypsy moth caterpillars prefer sweet chestnut leaves. The analyzed parameters which characterise the performance of the gypsy moth fourth-instar caterpillars are lower for all study oak species compared to sweet chestnut, except in the case of Turkey oak. Based on the study results and the adopted principle that the mixture should be composed of the most favourable species, which will serve as the 'trap plant' during the gypsy moth outbreak, it can be concluded that Turkey oak is more favourable for the mixture with sweet chestnut than the other analyzed oak species.

scholarly journals Occurrence of Erysiphe alphitoides in oak stands affected by flood disaster

2015 ◽  
Vol 76 (1) ◽  
pp. 73-77
Author(s):  
Wojciech Szewczyk ◽  
Robert Kuźmiński ◽  
Małgorzata Mańka ◽  
Hanna Kwaśna ◽  
Piotr Łakomy ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Statistical Significance ◽  
Carbon Assimilation ◽  
Stress Factors ◽  
Deciduous Tree ◽  
Pedunculate Oak ◽  
Oak Decline ◽  
Tree Vitality ◽  
Erysiphe Alphitoides ◽  
Assimilation Capacity

Abstract Pedunculate oak (Quercus robur L.) is the most valuable deciduous tree species in Poland. For almost 30 years, an oak decline resulting from stress factors leading to a decrease of tree vitality in the long-term has been observed. The aim of the present study was to determine the proportion of leaves infected by the fungus Erysiphe alphitoides, the cause of powdery mildew, in post-flood oak stands situated in the Forest District Wołów (51°32’N, 16°62’E) as well as to evaluate effects of powdery mildew with respect to the oak decline. In order to record the powdery mildew incidence, we selec ted three trees in each of the ten investigated oak stands, and 200 leaves were collected from the upper part of the crowns. The percentage of infected leaves as well as the reduction of carbon assimilation capacity was assessed. Furthermore, we evaluated the average reduction of carbon assimilation capacity and the percentage of withering branch tips in 25 adjacent trees. Incidences of powdery mildew were observed in seven out of the ten stands. The maximum tree damage did not exceed 22% leaf infection and mean defoliation within the study areas ranged from 18% to 61.4%. Non-withering branch tips were observed in one post-flood area as well as in one area situated outside the flooded region. Within the remaining areas studied, the average proportion of withering branch tips ranged from 0.4% to 13.8%. Statistical analyses showed that differences between the investigated stands with regard to the rate of powdery mildew occurrence were not significant. Correlating the means, however, revealed a relationship between powdery mildew incidence and branch tip withering. This relationship is a possible indication of the ongoing oak dieback. No statistically significant relationship between tree defoliation and powdery mildew incidence was found. The lack of statistical significance, as observed here, implies that water stagnation within the investigated stands had no effect on Erysiphe alphitoides infection.

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

2005 ◽  
pp. 9-29 ◽  
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.

scholarly journals Host plant effect on the susceptibility of gypsy moth caterpillars to insecticides

2002 ◽  
pp. 69-78
Author(s):  
Slobodan Milanovic
Keyword(s):  
Host Plant ◽  
Gypsy Moth ◽  
Lymantria Dispar ◽  
Abiotic Factors ◽  
Pedunculate Oak ◽  
Moth Population ◽  
Study Results ◽  
Turkey Oak ◽  
Host Plant Effect ◽  
Oak Leaves

Gypsy moth (Lymantria dispar L) is the most significant pest of broadleaf forests. The dynamics of gypsy moth population depends on several biotic and abiotic factors, but it is also highly dependent on the quality of consumed food. The gypsy moth control increasingly relies on the biological preparations based on Bacillus thuringiensis subspec. kurstaki (Btk) and Lymantria dispar Nuclear Poliedrosis virus (NPV). Chemical preparations are still applied although more rarely, the pyrethroids which include also lambda-cyhalothrin This paper presents the study results of the effect of host plant on gypsy moth caterpillar (Lymantria dispar L) susceptibility to lambda cihalotrine insecticide, by which the study oak leaves were contaminated. The study results show the lowest mortality of the caterpillars fed on contaminated leaves of Turkey oak (17.5%), then pedunculate oak (86.1%), and the highest mortality of caterpillars fed on sessile oak leaves (92%). The rate of the gypsy moth caterpillar development depends on the host plant Susceptibility of the gypsy moth caterpillars to the above preparation depends on the host plant The knowledge of the effect of host plant on insecticide efficiency in gypsy moth suppression would render insecticide utilisation optimal.

Undesirable Effects of Goal Setting on Perceived Fairness, Commitment, and Unethical Behavior

2018 ◽  
Vol 62 (2) ◽  
pp. 97-107 ◽  
Author(s):  
Nina Keith
Keyword(s):  
Goal Setting ◽  
Unethical Behavior ◽  
The United States ◽  
Goal Commitment ◽  
Management Technique ◽  
Long Term Effects ◽  
Perceived Fairness ◽  
Negative Effects ◽  
Positive Effects ◽  
And Performance

Abstract. The positive effects of goal setting on motivation and performance are among the most established findings of industrial–organizational psychology. Accordingly, goal setting is a common management technique. Lately, however, potential negative effects of goal-setting, for example, on unethical behavior, are increasingly being discussed. This research replicates and extends a laboratory experiment conducted in the United States. In one of three goal conditions (do-your-best goals, consistently high goals, increasingly high goals), 101 participants worked on a search task in five rounds. Half of them (transparency yes/no) were informed at the outset about goal development. We did not find the expected effects on unethical behavior but medium-to-large effects on subjective variables: Perceived fairness of goals and goal commitment were least favorable in the increasing-goal condition, particularly in later goal rounds. Results indicate that when designing goal-setting interventions, organizations may consider potential undesirable long-term effects.

Effect of leadership styles on organizational commitment and performance in small- and medium-sized enterprises in Iraqi Kurdistan

2020 ◽  
Vol 48 (9) ◽  
pp. 1-12
Author(s):  
Karwan Hamasalih Qadir ◽  
Mehmet Yeşiltaş
Keyword(s):  
Organizational Commitment ◽  
Organizational Performance ◽  
Leadership Styles ◽  
Chief Executive Officers ◽  
Chief Executive ◽  
Mediating Effect ◽  
Positive Effects ◽  
Iraqi Kurdistan ◽  
And Performance ◽  
Executive Officers

Since 2003 the number of small- and medium-sized enterprises (SMEs) has increased exponentially in Iraqi Kurdistan. To facilitate further growth the owners and chief executive officers of these enterprises have sought to improve their leadership skills. This study examined the effect of transactional and transformational leadership styles on organizational commitment and performance in Iraqi Kurdistan SMEs, and the mediating effect of organizational commitment in these relationships. We distributed 530 questionnaires and collected 400 valid responses (75% response rate) from 115 SME owners/chief executive officers and 285 employees. The results demonstrate there were positive effects of both types of leadership style on organizational performance. Further, the significant mediating effect of organizational commitment in both relationships shows the importance of this variable for leader effectiveness among entrepreneurs in Iraqi Kurdistan, and foreign entrepreneurs engaging in new businesses in the region.

scholarly journals Visual search behavior and performance in luggage screening: effects of time pressure, automation aid, and target expectancy

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Tobias Rieger ◽  
Lydia Heilmann ◽  
Dietrich Manzey
Keyword(s):  
Visual Search ◽  
Target Location ◽  
Time Pressure ◽  
Response Times ◽  
Search Behavior ◽  
High Time ◽  
Luggage Screening ◽  
Negative Effect ◽  
And Performance ◽  
Automated Support

AbstractVisual inspection of luggage using X-ray technology at airports is a time-sensitive task that is often supported by automated systems to increase performance and reduce workload. The present study evaluated how time pressure and automation support influence visual search behavior and performance in a simulated luggage screening task. Moreover, we also investigated how target expectancy (i.e., targets appearing in a target-often location or not) influenced performance and visual search behavior. We used a paradigm where participants used the mouse to uncover a portion of the screen which allowed us to track how much of the stimulus participants uncovered prior to their decision. Participants were randomly assigned to either a high (5-s time per trial) or a low (10-s time per trial) time-pressure condition. In half of the trials, participants were supported by an automated diagnostic aid (85% reliability) in deciding whether a threat item was present. Moreover, within each half, in target-present trials, targets appeared in a predictable location (i.e., 70% of targets appeared in the same quadrant of the image) to investigate effects of target expectancy. The results revealed better detection performance with low time pressure and faster response times with high time pressure. There was an overall negative effect of automation support because the automation was only moderately reliable. Participants also uncovered a smaller amount of the stimulus under high time pressure in target-absent trials. Target expectancy of target location improved accuracy, speed, and the amount of uncovered space needed for the search.Significance Statement Luggage screening is a safety–critical real-world visual search task which often has to be done under time pressure. The present research found that time pressure compromises performance and increases the risk to miss critical items even with automation support. Moreover, even highly reliable automated support may not improve performance if it does not exceed the manual capabilities of the human screener. Lastly, the present research also showed that heuristic search strategies (e.g., areas where targets appear more often) seem to guide attention also in luggage screening.

scholarly journals Extending the Coverage of the Trust–Acceptability Model: The Negative Effect of Trust in Government on Nuclear Power Acceptance in South Korea under a Nuclear Phase-Out Policy

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3343
Author(s):  
Seungkook Roh ◽  
Hae-Gyung Geong
Keyword(s):  
South Korea ◽  
Nuclear Power ◽  
Public Acceptance ◽  
Equation Modeling ◽  
Trust In Government ◽  
The Public ◽  
Positive Effects ◽  
Negative Effect ◽  
Nuclear Phase ◽  
Phase Out

This article extends the coverage of the trust–acceptability model to a new situation of nuclear phase-out by investigating the effect of trust on the public acceptance of nuclear power, with South Korea as the research setting. Through the structural equation modeling of a nationwide survey dataset from South Korea, we examined the effects of the public’s trust in the various actors related to nuclear power on their perceptions of the benefits and risks of nuclear power and their acceptance of nuclear power. Contrary to previous studies’ findings, in South Korea, under a nuclear phase-out policy by the government, trust in government revealed a negative impact on the public acceptance of nuclear power. Trust in environmental non-governmental groups also showed a negative effect on nuclear power acceptance. In contrast, trust in nuclear energy authority and trust in nuclear academia both had positive effects. In all cases, the effect of a trust variable on nuclear power acceptance was at least partially accounted for by the trust’s indirect effects through benefit perception and risk perception. These findings strengthen the external validity of the trust–acceptability model and provide implications for both researchers and practitioners.

scholarly journals Physical activity in elderly

2015 ◽  
Vol 25 (4) ◽  
pp. 249 ◽  
Author(s):  
Jan Cvecka ◽  
Veronika Tirpakova ◽  
Milan Sedliak ◽  
Helmut Kern ◽  
Winfried Mayr ◽  
...  
Keyword(s):  
Physical Activity ◽  
Electrical Stimulation ◽  
Muscle Mass ◽  
Irreversible Process ◽  
Significant Decline ◽  
Positive Effects ◽  
Age Related ◽  
And Performance ◽  
And Function ◽  
Age Related Changes

Aging is a multifactorial irreversible process associated with significant decline in muscle mass and neuromuscular functions. One of the most efficient methods to counteract age-related changes in muscle mass and function is physical exercise. An alternative effective intervention to improve muscle structure and performance is electrical stimulation. In the present work we present the positive effects of physical activity in elderly and a study where the effects of a 8-week period of functional electrical stimulation and strength training with proprioceptive stimulation in elderly are compared.

Effects of strategic information systems on competitive strategy and performance

2018 ◽  
Vol 67 (9) ◽  
pp. 2018-2045 ◽  
Author(s):  
Adilson Carlos Yoshikuni ◽  
Alberto Luiz Albertin
Keyword(s):  
Information Systems ◽  
Competitive Strategy ◽  
Corporate Performance ◽  
Equation Modeling ◽  
Strategic Information ◽  
Content Type ◽  
Strategic Information Systems ◽  
Positive Effects ◽  
Strategic Orientations ◽  
And Performance

Purpose This study argues that strategic information systems (SISs) are necessary for organizations’ survival and corporate performance in turbulent economic environments. Applying Miles and Snow’s strategy typology, the purpose of this paper is to explore how SIS supports business strategy and corporate performance. Design/methodology/approach This study uses quantitative survey data from 389 Brazilian companies during economic crises and analyzes them using structural equation modeling. Findings There is strong evidence that SIS promotes capacity and flexibility to create competitive strategies in response to environmental changes. SIS significantly and positively predicts firms’ use of prospector strategies, reducing the need to sacrifice efficiency for innovation. SIS can predict corporate performance more strongly than firms’ strategic orientations can. Practical implications The results provide organizations insights on how SIS enables strategic planning processes to create competitive strategy and improve performance during economic turbulence. Originality/value This research demonstrates SIS’s positive effects during economic turbulence on competitive strategy and performance, revealing that corporate performance is influenced more by SIS (strategic process) than strategic orientation (content). Hence, this study fills a research gap in the information systems strategy literature by contributing new insights about SIS.

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