Estimation of Cocoon Populations of the Larch Sawfly, Pristiphora erichsonii (Hartig)

1959 ◽  
Vol 91 (10) ◽  
pp. 650-661 ◽  
Author(s):  
W. G. H. Ives ◽  
W. J. Turnock
Keyword(s):  
Soil Sampling ◽  
The Other ◽  
Host Tree ◽  
Accurate Estimation ◽  
Mortality Factors ◽  
Factors Affecting ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly

This paper is one in a series on techniques used in estimating populations of various stages of the larch sawfly (Ives, 1955b; Ives and Prentice, 1958). This insect spends most of the year in cocoons in the soil beneath the host tree. The objective of accurate estimation of the cocoon population is to provide a basis for the evaluation of mortality factors affecting this stage. Two methods of estimation are considered in this paper. One is based on soil sampling (Part I) and the other on the number of cocoons formed in traps for falling larvae (Part 11).

Evaluation of Mortality During the Cocoon Stage of the Larch Sawfly, Pristiphora erichsonii (Htg.)

1962 ◽  
Vol 94 (9) ◽  
pp. 897-902 ◽  
Author(s):  
W. J. Turnock ◽  
W. G. H. Ives
Keyword(s):  
Research Team ◽  
Life Tables ◽  
Current Work ◽  
Population Estimates ◽  
Individual Factors ◽  
Mortality Factors ◽  
Factors Affecting ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly ◽  
Unbiased Estimates

This is one of a series of papers on the development of life tables for the larch sawfly, Pristiphora erichsonii (Htg.), by a research team at Winnipeg. Previous papers have described techniques for obtaining population estimates for eggs, cocoons, and adults (Ives, 1955; Ives and Turnock, 1959; Turnock, 1960), and current work is concerned with the development of methods of segregating and evaluating the mortality factors affecting each stage. This paper describes the methods used to evaluate the amount of mortality caused by individual factors in the cocoon stage and discusses the problems of obtaining accurate and unbiased estimates.

Mortality of Cocoons of the Larch Sawfly, Pristiphora erichsonii (Htg.), in Relation to Distance from Small-Mammal Tunnels

1959 ◽  
Vol 91 (9) ◽  
pp. 535-542 ◽  
Author(s):  
C. H. Buckner
Keyword(s):  
Small Mammals ◽  
Small Mammal ◽  
Natural Mortality ◽  
Mortality Factors ◽  
Forest Reserve ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly ◽  
The Relationship

The relationship between the fate of cocoons of the larch sawfly, Pristiphora erichsonii (Htg.), and distance from small-mammal tunnels was studied during 1958 in the Whiteshell Forest Reserve of eastern Manitoba. The objects were to determine the distance that small mammals can detect cocoons and to observe possible effects of the interactions of small-mammal predation and other natural mortality factors of the insect. Additional analyses of the data provided information on the behaviour of the predators and the ecology of the prey insect.

Population Dynamics of the Larch Sawfly

1964 ◽  
Vol 96 (1-2) ◽  
pp. 160-161 ◽  
Author(s):  
Keyword(s):  
Biological Control ◽  
Population Dynamics ◽  
Life Table ◽  
Quantitative Methods ◽  
Population Data ◽  
Natural Control ◽  
Mortality Factors ◽  
Ecological Relationships ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly

The larch sawfly, Pristiphora erichsonii (Htg.), has been studied in Manitoba for over 50 years, since the first outbreaks led to the introduction of the European parasite, Mesoleius tenthredinis Morley. This parasite was credited with reducing the severity of early outbreaks but when host populations again increased in the early 1940's, it was found that M. tenthredinis was ineffective due to the ability of host larvae to encapsulate parasite eggs. Intensive studies of individual mortality factors were initiated at the Winnipeg Laboratory as staff and facilities were expanded in the late 1940's. Development of the life-table concept of recording population data (Morris and Miller 1954) led to co-ordination of several projects until by 1955 a team of research officers was engaged in comprehensive studies of general ecological relationships, parasitism, vertebrate predation, and the effect of defoliation on host stands. Members of the team currently engaged in population dynamics studies and responsible for this exhibit are: Dr.C. H. Buckner, vertebrate predators; W. G. H. Ives, quantitative methods and natural control; L. D. Nairn, interrelations with host tree; Dr. W. J. Turnock, natural and biological control, bioclimatology. Other Winnipeg officers working on related larch sawfly projects are Dr. R. J. Heron, physiological studies, and J. A. Muldrew, biological control with particular reference to immunity to M. tenthredinis.

Estimation of Adult Populations of the Larch Sawfly, Pristiphora erichsonii (Htg.)

1960 ◽  
Vol 92 (9) ◽  
pp. 659-662 ◽  
Author(s):  
W. J. Turnock
Keyword(s):  
Mortality Factors ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly

This paper is one in a series on techniques for estimating populations of various stages of the larch sawfly (Ives, 1055; Ives and Prentice, 1958; Ives and Turnock, 1959) to provide's basis for the evaluation of mortality factors. The larch sawfly overwinters in a cocoon in the soil and adults emerge during the spring and summer (Turnock, 1960). This paper describes the methods and results of sampling adults as they emerge from the soil.

FACTORS AFFECTING THE MORTALITY OF LEAFMINERS ARGYRESTHIA THUIELLA AND PULICALVARIA THUJAELLA (LEPIDOPTERA: YPONOMEUTIDAE AND GELECHIIDAE) ON EASTERN WHITE CEDAR, IN ONTARIO

1979 ◽  
Vol 111 (11) ◽  
pp. 1299-1306 ◽  
Author(s):  
N. L. Bazinet ◽  
M. K. Sears
Keyword(s):  
Host Species ◽  
Life Tables ◽  
Mortality Factors ◽  
Factors Affecting ◽  
White Cedar ◽  
Eastern White Cedar ◽  
Overwintering Mortality

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.

scholarly journals Germination, Establishment, and Mortality of Naturally Seeded Southwestern Ponderosa Pine

2003 ◽  
Vol 18 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Steven J. Stein ◽  
Diana N. Kimberling
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Mineral Soil ◽  
Mortality Data ◽  
Mortality Factors ◽  
Seedling Mortality ◽  
Prescribed Burns ◽  
Factors Affecting ◽  
Northern Arizona ◽  
Lepidopteran Larvae

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.

scholarly journals Two methods of assessing the mortality factors affecting the larvae and pupae of Cameraria ohridella in the leaves of Aesculus hippocastanum in Switzerland and Bulgaria

2007 ◽  
Vol 97 (5) ◽  
pp. 445-453 ◽  
Author(s):  
S. Girardoz ◽  
R. Tomov ◽  
R. Eschen ◽  
D.L.J. Quicke ◽  
M. Kenis
Keyword(s):  
Leaf Senescence ◽  
Sampling Method ◽  
Plant Defence ◽  
Leaf Miner ◽  
Mortality Factor ◽  
Horse Chestnut ◽  
Mortality Factors ◽  
Grab Sampling ◽  
Defence Reaction ◽  
Factors Affecting

AbstractThe horse-chestnut leaf miner, Cameraria ohridella, is an invasive alien species defoliating horse-chestnut, a popular ornamental tree in Europe. This paper presents quantitative data on mortality factors affecting larvae and pupae of the leaf miner in Switzerland and Bulgaria, both in urban and forest environments. Two sampling methods were used and compared: a cohort method, consisting of the surveying of pre-selected mines throughout their development, and a grab sampling method, consisting of single sets of leaves collected and dissected at regular intervals. The total mortality per generation varied between 14 and 99%. Mortality was caused by a variety of factors, including parasitism, host feeding, predation by birds and arthropods, plant defence reaction, leaf senescence, intra-specific competition and inter-specific competition with a fungal disease. Significant interactions were found between mortality factors and sampling methods, countries, environments and generation. No mortality factor was dominant throughout the sites, generations and methods tested. Plant defence reactions constituted the main mortality factor for the first two larval stages, whereas predation by birds and arthropods and parasitism were more important in older larvae and pupae. Mortality caused by leaf senescence was often the dominant mortality factor in the last annual generation. The cohort method detected higher mortality rates than the grab sampling method. In particular, mortality by plant defence reaction and leaf senescence were better assessed using the cohort method, which is, therefore, recommended for life table studies on leaf miners.

Investigation on Polymer Adsorption and Retention in a Polymer Flooded Reservoir

2013 ◽  
Vol 734-737 ◽  
pp. 1200-1203
Author(s):  
Shu Qiang Liu ◽  
Ji Cheng Zhang ◽  
Jin Cheng Xu
Keyword(s):  
Polymer Solution ◽  
Influencing Factors ◽  
Polymer Adsorption ◽  
Solution Concentration ◽  
Injection Rate ◽  
The Other ◽  
Injection Time ◽  
Factors Affecting ◽  
Dynamic Factors ◽  
Polymer Retention

During polymer flooding, certain amount of polymer would be lost. Polymer retention causes sweep volume expanding on one side, it also causes polymer loss on the other. Therefore, it is a very important topic to study the influencing factors of polymer retention. There are many factors affecting polymer retention process. This paper mainly studied the influence from dynamic factors such as polymer solution concentration, injection rate, injection time, injected pv number. This paper investigated the influence of these factors on polymer retention process, and optimized these factors to minimize polymer loss in reservoir.

Factors affecting changes in the intraocular pressure after phacoemulsification surgery

2020 ◽  
Vol 1 (3) ◽  
pp. 166-172
Author(s):  
Rita Dhamankar ◽  
◽  
Suhas S Haldipurkar ◽  
Tanvi Haldipurkar ◽  
Vijay Shetty ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Anterior Chamber ◽  
Axial Length ◽  
Anterior Chamber Depth ◽  
The Other ◽  
Factors Affecting ◽  
Factors Associated ◽  
Post Surgery ◽  
Unit Increase ◽  
The Mean

AIM: To assess the changes in anterior chamber parameters and examine the factors associated with changes in the intraocular pressure (IOP) in individuals who have undergone phacoemulsification surgery. METHODS: It is a longitudinal analysis of secondary clinical data collected from 105 non-glaucomatous eyes (82 patients) undergoing a cataract surgery. We studied the association between anterior chamber parameters, grade of cataract, demographics, and changes in the IOP over a period of three weeks. We also evaluated the association between the pressure-depth (PD) ratio and changes in the IOP during this time. RESULTS: The mean age (SD) of the 82 patients was 60.1±7.8y. The mean±standard deviation (SD) IOP was 15.06±3.36 mm Hg pre-operatively; it increased to 15.75±4.21 mm Hg on day one (P=0.20). In the multifactorial models, the mean IOP was -1.715 (95%CI: -2.795, -0.636) mm Hg on day 21±5 compared with the pre-operative values. The anterior chamber depth (ACD), axial length, age, sex, and grade of cataract were not significantly associated with changes in the IOP. Each unit increase in the PD ratio was associated with an increase in the mean IOP by 1.289 mm Hg (95%CI: 0.906, 1.671). After adjusting for pre-operative PD ratio, none of the other variables (ACD, axial length, temporal angle) were significantly associated with changes in mean IOP. CONCLUSION: The PD ratio was the single most important factor associated with the changes in post-operative IOP over three weeks post-surgery.

Pristiphora erichsonii. [Distribution map].

1959 ◽  
Author(s):  
Keyword(s):  
North America ◽  
Geographical Distribution ◽  
Distribution Map ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly ◽  
New Distribution ◽  
Distribution In Europe

Abstract A new distribution map is provided for Pristiphora erichsonii (Htg.) (Hymenopt., Tenthredinoidea) (Larch Sawfly). Hosts: Larix spp. Information is given on the geographical distribution in EUROPE (excl. USSR), Austria, Britain, Czechoslovakia, Denmark, Finland, France, Germany, Ireland, Netherlands, Norway, Poland, Rumania, Sweden, ASIA (excl. USSR), Japan, USSR, NORTH AMERICA, Canada, U.S.A.

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