scholarly journals The second outbreak of the poplar leafminer Phyllonorycter populifoliella in St. Petersburg

Author(s):  
Н.А. Мамаев ◽  
Д.Д. Буй ◽  
А.В. Селиховкин

Исследовались популяционные характеристики, факторы смертности и пищевые предпочтения минирующей листья тополя тополёвой нижнесторонней моли-пестрянки Phyllonorycter populifoliella (Treitshke, 1833) (Lepidoptera: Gracillariidae) в Санкт-Петербурге в связи с развитием второй в истории насаждений города вспышки массового размножения этого вредителя. В разных районах Санкт-Петербурга были заложены пробные площади с разной интенсивностью повреждения, варьирующей в среднем от 5,2 до 21,7 мин/лист. На каждой пробной площади в первые дни после начала лёта первого поколения (первая декада августа) срезались по две ветви в нижней части кроны с каждого дерева на которых анализировались мины 50 листьев для установления причин гибели и доли выживших особей. На всех пробных участках (за одним исключением) был один вид тополя - тополь берлинский Populus × berolinensis. Именно этот вид наиболее интенсивно повреждался Ph. populifoliella. Вспышка размножения в 2017-2019 гг., локализованная в Невском районе, постепенно распространяется по территории города, имея выраженный мозаичный характер,однако причины этой мозаичности распространения не ясны. Плотность популяции вредителя в Невском районе за последние годы существенно увеличилась. Наиболее успешно проходит развитие на деревьях с высокой плотностью популяции вредителя. С одного листа на таких участках вылетает 7 и более бабочек (36-52%) от начавших развиваться личинок), тогда как при меньшей плотности (в среднем 5 и 11 мин/лист) вылет составляет 8 и 19% соответственно. Это позволяет сделать предположение о ведущей роли состояния кормовых деревьев в развитии тополёвой моли. В отношении остальных факторов, влияющих на смертность, не удалось выявить их выраженного воздействия на плотность популяции. Population characteristics, mortality factors, and food preferences of the moth Phyllonorycter populifoliella (Treitshke, 1833) (Lepidoptera: Gracillariidae) mining leaves of poplar in St. Petersburg were studied under conditions of the second outbreak of this pest in the history of the urban plantings in St. Petersburg. In different districts of St. Petersburg, sample plots were established with different intensity of damage by the poplar leafminer, varying from 5.2 to 21.7 mines per leaf. On each sample plot, in the first days after the beginning of the flight of the first generation adults (the first ten days of August), two branches were cut in the lower part of the crown from each test tree, on which mines of at least 50 leaves were collected and analyzed to establish the causes of death and the proportion of the surviving individuals. With one exception, all sample plots were represented by one poplar species - the Berlin poplar Populus × berolinensis. This species was most intensively damaged by Ph. populifoliella . Outbreak in 2017- 2019 was initially localized in the Nevsky District and then gradually spread throughout the city, having the pronounced mosaic character, however, the reasons for the mosaic distribution of the outbreak are unclear. The density of the pest population has increased significantly in the Nevsky District over the past years. Development of the moth is most successful on trees with a high population density of the pest. Seven or more adult moths emerge from one leaf in such areas (36-52% of the larvae that begun to develop), while at a lower density (on average, 5-11 mines per leaf), the emergence was 8 and 19%, respectively. This finding allows us to assume the leading role of the state of forage trees in the development of the poplar leafminer. Contribution of the other factors affecting larval mortality was not possible to evaluate.

1988 ◽  
Vol 120 (10) ◽  
pp. 841-853 ◽  
Author(s):  
Dennis A. Lee

AbstractA combination of laboratory and field trials, from 1983 to 1985, were used to determine mortality factors affecting all life stages of Alberta populations of the European corn borer, Ostrinia nubilalis (Hübner), feeding on corn. The resulting life table demonstrated that greatest mortality occurred during the first and second larval instars (62.2%), when mature larvae are in diapause (69.5%), and from moth migration and loss in reproductive potential (70.3%). Stages where mortality was slight included the egg stage (11.7%), non-diapausing third- to fifth-instar larvae (2%), and pupae (10.4%).Laboratory trials showed that greater egg mortality occurred at relative humidities (RH) of 35 and 55% than at a RH of 75%. In the field, egg parasitism was nil, predation of early-instar larvae (5.2%) and diapausing larvae (6%) was low, and parasitoids were scarce (emerging from ca. 2% of pupae). Sustained periods of hot, dry weather with high moisture stress were related to mortality of both eggs and early-instar larvae. Death of early-instar larvae also was related to periods of rainy weather with low evaporation. The 64% non-diapause larval mortality was much lower than that reported elsewhere. The dramatic increase in the corn borer since its recent introduction to Alberta may be due to a lack of natural enemies, and because only non-resistant corn hybrids are grown.


2017 ◽  
Author(s):  
Lyudmila Grudtsyna ◽  
Alyeksandr CHyernyavskiy ◽  
Dmitriy Pashentsev

The monograph is devoted to the study of the role of government in shaping, support and development of Russia´s civil society institutions. by the authors E practical examples and using the theoretical and legal structures proved the leading role of the state in the formation of Russian civil society, which is based in Russia "from below", according to the classical western models, and "from above", taking into account the centuries-old traditions and the history of the Russian people and the Russian statehood. The state acts as the management system in relation to civil society as a managed system. However, civil society functions as a self-regulating social system, the determining state. The fact that civil society - self-regulating system, and at the same time controlled, there is no contradiction. The book will be of interest to lawyers, political scientists, sociologists, public servants, students, graduate students and faculty of liberal arts colleges and faculties, as well as all interested in the development of civil society in Russia and the role of the state in this process.


1972 ◽  
Vol 104 (5) ◽  
pp. 705-710 ◽  
Author(s):  
J. A. Witter ◽  
H. M. Kulman

AbstractParasitism, infertility, and death of fully developed first-stage larvae in eggs (pharate larvae) were the egg mortality factors encountered during a 1967–69 study on the bionomics of the forest tent caterpillar, Malacosoma disstria Hübner, in northern Minnesota. There was no significant difference in the average yearly per cent parasitization and infertility per egg mass; these ranged from 7 to 10% and 1 to 3%, respectively. There was a year to year difference in pharate larval mortality. It ranged from 39% in 1968 to only 9 and 3% for 1967 and 969. Studies showed that egg masses had a tendency to be either nearly complete y hatched or unhatched only in 1968. The variation in pharate larval mortally in these studies suggests qualitative differences in the population. The pharate larval mortality has the potential of influencing population trends of the forest tent caterpillar.


2004 ◽  
Vol 2 (2) ◽  
pp. 188-197 ◽  
Author(s):  
Nur Masalha

In 1948 an official ‘Transfer Committee’ was appointed by the Israeli Cabinet to plan the Palestinian refugees' resettlement in the Arab states. Apart from doing everything possible to reduce the Arab population in Israel, the Transfer Committee sought to amplify and consolidate the demographic transformation of Palestine by: preventing the Palestinian refugees from returning to their homes; the destruction of Arab villages; settlement of Jews in Arab villages and towns; and launching a propaganda campaign to discourage Arab return. One of the Transfer Committee's initiatives was to invite Dr Joseph Schechtman, a right-wing Zionist Revisionist leader and expert on ‘population transfer’, to join its efforts. In 1952 Schechtman published a propagandists work entitled The Arab Refugee Problem. Since then Schechtman would become the single most influential propagator of the Zionist myth of ‘voluntary’ exodus in 1948. This article examines the leading role played by Schechtman in promoting Israeli propaganda and politics of denial. Relying on newly-discovered Israeli archival documents, the article deals with little known and new aspects of the secret history of the post-1948 period.


2018 ◽  
Vol 28 (7) ◽  
pp. 2417-2425
Author(s):  
Peter Peikov ◽  
Borana Hadjieva

The present paper reveals the significance of the National Archival Fund for preservation of the historical and cultural memory of the Bulgarian nation and the formation of historical consciousness. The National Archives Fund is defined as the largest collection of documents with historical, scientific, social, economic, cultural significance as an essential part of the cultural and historical heritage of Bulgaria.It treasures documents about the history of thousands of institutions and prominent figures of the state, economy, culture and art, of ordinary citizens whose activity is historically important in one respect or another.The emphasis of the study is on the main factors determining the daily enrichment of the National Archival Fund with new documents. Among these key factors are development of documentaristics and archivistics, trends in social development, ideological and political climate, financial stability and attitude of the society as a whole, of the istitutional leaders and administrative heads, creating documents, in particular, of the non-governmental organizations and even of the individual citizen to the problems in the field of archivistics.In the focus of the paper as well is the leading role of the state archives for the formation of the National Archival Fund of Bulgaria and the opportunities for cooperation with museums, libraries, community centers and other institutions of memory working with the same purpose and vision.


2017 ◽  
Vol 6 (7) ◽  
pp. 5426 ◽  
Author(s):  
Hiren J. Patel ◽  
Vaishnavi P. Parikh

The pharmaceutical industry has faced several marked challenges in order to bring new chemical entities (NCEs) into the market over the past few decades. Various novel drug delivery approaches have been used as a part of life cycle management from which Osmotic drug delivery systems look the most promising one. After discussing the history of osmotic pump development, this article looks at the principles, advantages and disadvantages of osmotic drug delivery systems. Then, the basic components of osmotic pump and factors affecting the design of oral osmotic drug delivery systems are discussed in detail. In the later part of the manuscript, various types of osmotic pumps available in the market and evaluation methods for osmotic drug delivery systems are discussed in detail.


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
V.L Malavasi ◽  
E Fantecchi ◽  
V Tordoni ◽  
L Melara ◽  
A Barbieri ◽  
...  

Abstract Background Natural history of atrial fibrillation (AF) shows a progression of arrhythmia from non-permanent to permanent AF. Permanent AF was found associated with a worse prognosis than non-permanent one. Aim To assess the factors associated with progression to permanent AF in an unselected population of AF patients with non-permanent AF. Methods In this prospective study we enrolled in- as well as out-patients with non-permanent AF and age ≥18 years, with at least one episode of ECG-documented AF within 1 year. The patients were followed-up at 1 month and every 6 months thereafter. Results Out of 523 patients, 314 (60%) were in non-permanent AF (80 [25.5%] paroxysmal AF, 165 [52.5%] persistent AF, 69 [2%] first diagnosed AF), mostly male (188, 59.9%), median age 71 years (IQ range 62–77), median CHA2DS2VASc 3 (1–4), median HATCH score 1 (1–2). After a median follow-up of 701 (IQ range 437–902) days, 66 patients (21%) showed permanent AF. CHA2DS2VASc and HATCH scores were incrementally associated to progression to permanent AF (CHA2DS2VASc χ2 p=0.001; HATCH χ2 p=0.017; p for trend CHA2DS2VASc <0.001, HATCH p=0.001). At multivariable Cox proportional hazard regression the following variables were significantly associated with AF progression: age (hazard ratio [HR] 1.041; 95% CI: 1.004–1.079; p=0.028), at least moderate left atrial (LA) enlargement (>42 ml/m2) (HR 2.092; 95% CI: 1.132–3.866; p=0.018), antiarrhythmics drugs after the enrollment (HR 0.087; 95% CI: 0.011–0.662; p=0.018), EHRA score >2 (HR 0.351; 95% CI: 0.158–0.779; p=0.010) and Valvular HD (HR 2.161; 95% CI: 1.057–4.420; p=0.035). Adding LA dilation to HATCH score (HATCH-LA) and assigning 2 points based on multivariable Cox regression, HATCH-LA was statistically better in ROC curves in prediction of AF progression vs HATCH score (area under the curve 0.695 vs 0.636; DeLong p=0.0225). Survival-free curves on freedom from permanent AF using as discriminator HATCH-LA score ≤2 vs >2 led to a statistically significant difference (χ2=16.080 p<0.001), but the same was not found for HATCH score (χ2 =3.099; p=0.078). Conclusions In patients without permanent AF, progression of AF was independentely related to age, LA dilation, AF symptoms severity, antiarrhythmic drugs and Valvular HD. HATCH score predicted AF progression and adding to it LA dilation (at least moderate) improved patients stratification for the risk of evolution to permanent AF. Funding Acknowledgement Type of funding source: None


Insects ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 48
Author(s):  
Mio Amemiya ◽  
Kôji Sasakawa

Thanatosis, also called death feigning, is often an antipredator behavior. In insects, it has been reported from species of various orders, but knowledge of this behavior in Hymenoptera is insufficient. This study examined the effects of sex, age (0 or 2 days old), temperature (18 or 25 °C), and background color (white, green, or brown) on thanatosis in the braconid parasitoid wasp Heterospilus prosopidis. Thanatosis was more frequent in 0-d-old individuals and in females at 18 °C. The duration of thanatosis was longer in females, but this effect of sex was weaker at 18 °C and in 0-d-old individuals. The background color affected neither the frequency nor duration. These results were compared with reports for other insects and predictions based on the life history of this species, and are discussed from an ecological perspective.


1979 ◽  
Vol 111 (11) ◽  
pp. 1299-1306 ◽  
Author(s):  
N. L. Bazinet ◽  
M. K. Sears

AbstractMortality factors affecting populations of the leafminers Argyresthia thuiella (Pack.) and Pulicalvaria thujaella (Kft.), on eastern white cedar in the area of Guelph, Ontario were identified and summarized in life tables. During the two annual generations studied from 1975 to 1977, overwintering mortality varied widely. Winterkill increased from 6.8% to 62.9% for A. thuiella and from 8.1% to 54.6% for P. thujaella, from 1976 to 1977. Several parasitoids produced substantial mortality of each host species, but their effect may have been superseded by winterkill in 1977. Data indicate that both populations of leafminers increased from 1975 to 1976 but decreased substantially from 1976 to 1977.


2003 ◽  
Vol 18 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Steven J. Stein ◽  
Diana N. Kimberling

Abstract Information on the mortality factors affecting naturally seeded conifer seedlings is becoming increasingly important to forest managers for both economic and ecological reasons. Mortality factors affecting ponderosa pine (Pinus ponderosa) seedlings immediately following natural germination and through the following year were monitored in Northern Arizona. The four major mortality factors in temporal order included the failure of roots to establish in the soil (27%), herbivory by lepidopteran larvae (28%), desiccation (30%), and winterkill (10%). These mortality factors were compared among seedlings germinating in three different overstory densities and an experimental water treatment. Seedlings that were experimentally watered experienced greater mortality than natural seedlings due to herbivory (40%), nearly as much mortality due to the failure of roots to establish in the soil (20%), less mortality due to winterkill (5%), and no mortality due to desiccation. The seedling mortality data through time were summarized using survivorship curves and life tables. Our results suggest that managers should consider using prescribed burns to decrease the percentage of seedlings that die from failure of their roots to reach mineral soil and from attack by lepidopteran larvae. West. J. Appl. For. 18(2):109–114.


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