FACTORS AFFECTING DIAPAUSE DEVELOPMENT AND SURVIVAL IN THE PUPA OF MAMESTRA CONFIGURATA (LEPIDOPTERA: NOCTUIDAE)

1978 ◽  
Vol 110 (2) ◽  
pp. 183-191 ◽  
Author(s):  
Robert P. Bodnaryk
Keyword(s):  
Laboratory Tests ◽  
Endocrine System ◽  
Total Mortality ◽  
Western Canada ◽  
Factors Affecting ◽  
Soil Temperatures ◽  
Diapause Development ◽  
Pupal Mortality ◽  
Lepidoptera Noctuidae ◽  
Significant Mortality

AbstractOnly soil temperatures below −7°C are likely to cause significant pupal mortality of M. configurata in the field, and only if exposure periods are sufficiently prolonged. At −17°C, a temperature not uncommonly encountered in the soil at 10 cm during the prairie winter, near total mortality occurred within 1 week in laboratory tests and significant mortality (20–30%) occurred within 1 day. The survival time at −12°C was considerably longer, and 50% mortality occurred after about 6 weeks of exposure. Pupal mortality caused by cold might thus vary from 0 to 100% depending on local climatic and field conditions and therefore is an essential component of a survival model for the species.Exposure to cold accelerates diapause development by as much as four orders of magnitude for the lowest temperature tested (−17°C). However, the acceleration of diapause development by sub-zero temperatures appears to be of limited phenological significance, since in western Canada the pupae spend at least 40 weeks in the soil and can easily complete diapause development within this time at 0° to 5°C. Further evidence for a major reorganization of the endocrine system of M. configurata pupae during stage 2 of diapause development is presented.

Laboratory Tests on Engineering Properties of Wind-Blown Sand

2012 ◽  
Vol 170-173 ◽  
pp. 706-709
Author(s):  
Zhao Lin Jia ◽  
Shu Wang Yan ◽  
Zhi Liang Huo
Keyword(s):  
Water Content ◽  
Laboratory Tests ◽  
Fine Sand ◽  
Engineering Properties ◽  
Grain Composition ◽  
Factors Affecting ◽  
Compaction Curve ◽  
Main Factors ◽  
Dry And Wet Conditions ◽  
Compaction Properties

By means of laboratory tests and theoretical calculation, the physical, mechanical properties and compaction mechanism of the wind-blown sand are studied to deal with the problem of how to use the wind-blown sand as roadbed materials. It is revealed that water content doesn’t affect the compressibility and the shear strength of the wind-blown sand obviously and the wind-blown sand can be compacted both in dry and wet conditions. The compaction curve of the ordinary fine sand is consistent with that of wind-blown sand and the main factors affecting the compaction properties are the grain composition, water content and compaction work.

scholarly journals Effect of aqueous neem seed extract via irrigation on larvae of Liriomyza sativae in melon crop

2018 ◽  
Vol 36 (3) ◽  
pp. 353-356 ◽  
Author(s):  
Ewerton M Costa ◽  
Francisco EL Silva ◽  
Elton L Araujo
Keyword(s):  
Larval Mortality ◽  
Total Mortality ◽  
Seed Extract ◽  
Neem Seed ◽  
Liriomyza Sativae ◽  
Randomized Design ◽  
Soil Irrigation ◽  
Completely Randomized Design ◽  
Pupal Mortality ◽  
Neem Seed Extract

ABSTRACT The leafminer [Liriomyza sativae (Diptera: Agromyzidae)] is one of the main pests of melon crop (Cucumis melo) in the states of Rio Grande do Norte and Ceará. Thus, adopting strategies to control this destructive insect is essential. The aim of this study was to evaluate the effect of aqueous neem seed extract, applied to soil via irrigation, on leafminer larvae, in the melon crop. An experiment was conducted in greenhouse, in completely randomized design, consisting of five treatments (four doses of aqueous neem seed extract: 1; 3; 5 and 10 g/100 mL) and the control consisting only of distilled water and 10 replicates (melon plants). The treatments were applied in a single dose, via soil irrigation. In the first stage of the evaluation, 24 hours after application, the number of dead larvae per plant was counted. In the second step, pupal mortality was recorded. The total mortality was also calculated considering the number of larvae and the number of emerged adults. We verified that, increasing the concentration of aqueous neem seed extract, an increase in the larval and pupal mortality of the leafminer in melon crop was noticed. The concentration 10 g/100 mL presented the best results, resulting in 36.4% of larval mortality, 96.5% of pupal mortality and 96.8% of total mortality.

scholarly journals Spring emergence of Canadian Delia radicum and synchronization with its natural enemy, Aleochara bilineata

2010 ◽  
Vol 142 (3) ◽  
pp. 234-249 ◽  
Author(s):  
L.D. Andreassen ◽  
U. Kuhlmann ◽  
J.W. Whistlecraft ◽  
J.J. Soroka ◽  
P.G. Mason ◽  
...  
Keyword(s):  
Adult Emergence ◽  
Development Rate ◽  
Delia Radicum ◽  
Aleochara Bilineata ◽  
Development Rates ◽  
Models Of Development ◽  
Soil Temperatures ◽  
Truncated Normal ◽  
Diapause Development ◽  
Spring Emergence

AbstractTo characterize time of spring emergence following post-diapause development, Delia radicum (L.) (Diptera: Anthomyiidae) from Saskatchewan, Manitoba, and southwestern Ontario were collected in fall, maintained over winter at 1 °C, then transferred to higher constant temperatures until adult emergence. At each location there were “early” and “late” phenotypes. Truncated normal models of temperature dependency of development rate were fitted for each phenotype from each location. We provide the first evidence of geographic variation in the criteria separating these phenotypes. Separation criteria and models for early and late phenotypes at the two prairie locations, approximately 700 km apart, were indistinguishable, but differed from those for Ontario. Prairie phenotypes developed more slowly than Ontario phenotypes, and more prairie individuals were of the late phenotype. Poor synchronization of spring emergence could impair predation of D. radicum eggs by adult Aleochara bilineata Gyllenhal (Coleoptera: Staphylinidae). Aleochara bilineata from Manitoba were reared and development rates modelled as for D. radicum. Models of development rates for the two species, when combined with simulated soil temperatures for two prairie locations, suggest that emergence of adult A. bilineata is well synchronized with availability of D. radicum eggs in prairie canola.

SURVIVAL OF PUPAE OF MAMESTRA CONFIGURATA (LEPIDOPTERA: NOCTUIDAE) AND TWO OF ITS PARASITES IN UNTILLED AND TILLED SOIL

1984 ◽  
Vol 116 (2) ◽  
pp. 257-267 ◽  
Author(s):  
W. J. Turnock ◽  
R.J. Bilodeau
Keyword(s):  
Soil Type ◽  
Brassica Campestris ◽  
Total Mortality ◽  
Pupal Stage ◽  
Mamestra Configurata ◽  
Overwintering Mortality ◽  
Lepidoptera Noctuidae ◽  
Athrycia Cinerea

AbstractThe survival of Mamestra configurata Wlk. was determined from autumn and spring samples in 1973/74, 1980/81, and 1981/82 taken from unfilled and tilled portions of 12 fields of canola (Brassica campestris L. and B. napus L.). Survival from the pre-pupal stage in the autumn to post-diapause pupae in the spring varied from 2.9 to 56.5% in unfilled soil and from 0 to 25.4% in tilled soil. In untilled soil, the variations among fields in total mortality of M. configurata were related to parasitism by Banchus flavescens and to overwintering mortality. In tilled soil, overwintering mortality accounted for most of the variability in total mortality among fields. The percentage of mortality from injury to pupae, and their disappearance following tillage, greatly increased but this type of mortality did not account for much of the variability in total mortality. The disappearance of pupae following tillage was attributed to predation. In both untilled and tilled soils, the amount of overwintering mortality was related to the depth of accumulated snow, and mortality was lower in untilled soil because the stubble trapped more snow. The survival of M. configurata was not related to soil type, the type of tillage equipment, or the frequency of tillage. The number of adults emerging from untilled and tilled soil in one field were 2.58 and 0.27/m2 for M. configurata, 5.22 and 2.85/m2 for the parasite B. flavescens, and 4.46 and 3.60/m2 for the parasite Athrycia cinerea, indicating that the survival of the parasites was less affected by tillage than that of their host.Tillage may reduce the frequency and severity of outbreaks of M. configurata not only by increasing mortality but also by differentially affecting the survival of its main parasites.

scholarly journals Assessment of Mortality and Factors Affecting Outcome of Use of Paclitaxel-Coated Stents and Bare Metal Stents in Femoropopliteal PAD

2020 ◽  
Vol 9 (7) ◽  
pp. 2221
Author(s):  
Aleksander Falkowski ◽  
Hubert Bogacki ◽  
Marcin Szemitko
Keyword(s):  
Clinical Benefit ◽  
Neointimal Hyperplasia ◽  
Randomized Study ◽  
Bare Metal Stents ◽  
Total Mortality ◽  
Arterial Disease ◽  
Metal Stents ◽  
Bare Metal ◽  
Factors Affecting ◽  
Increased Risk

The use of drug-coated devices in intravascular therapy is aimed at preventing neointimal hyperplasia caused by excessive proliferation of vascular smooth muscle and thereby restenosis. Although its use seemed initially promising, a recent publication has shown an increased risk of mortality with paclitaxel-coated devices, and there is an urgent need to reaffirm assessments of drug-eluting stents (DES). Objective: The aim of the study was to compare mortality and effectiveness of paclitaxel-coated stents and bare-metal stents (BMS) in the treatment of peripheral arterial disease (PAD) with long-term follow-up. Materials and methods: In a single center randomized study, 256 patients with PAD were treated intravascularly with stent implantation. Patients were randomized into two groups: the first (n = 126) were treated with DES, and the second (n = 130) were treated with BMS. The study included evaluation after the procedure, after about 6 months and 36 months. Co-morbidities, with risks for atherosclerosis, were analyzed in all patients. Patients were evaluated for clinical outcome, restenosis frequency, and safety (complications and total mortality). Results: Clinical benefit at the end of the investigation was statistically significantly better in the DES group compared with the BMS group: 85.7% versus 66.2% (p = 0.0003), respectively. Restenosis occurred significantly less frequently in patients with DES: 16.0% versus BMS: 35.0%, p = 0.012. There was no significant effect of comorbidities on the frequency of restenoses. There were no differences in all-cause mortality over the three years with paclitaxel and no-paclitaxel stents cohorts (8.7% versus 7.1%; long-rank p = 0.575). No association was found with mortality and treatment with DES or BMS. Conclusions: The use of paclitaxel-coated stents gave good clinical benefit and caused a significantly lower frequency of restenosis compared to bare-metal stents. The use of paclitaxel-coated stents did not increase mortality.

Mechanism of Rubber Cracking

1946 ◽  
Vol 19 (2) ◽  
pp. 406-416 ◽  
Author(s):  
E. F. Powell ◽  
V. E. Gough
Keyword(s):  
Laboratory Tests ◽  
Surface Film ◽  
Factors Affecting ◽  
Laboratory Conditions ◽  
Service Conditions ◽  
Exposure Conditions

Abstract Rubber and rubberlike polymers, in common with other materials which deteriorate on exposure to oxidizing or similar agents, eventually crack under normal atmospheric service conditions. The present paper confines itself to the factors affecting the type and appearance of the cracking which eventually occurs when a surface film of a rubber object (particularly when stressed) hardens and deteriorates in strength from any cause whatsoever. The importance of an understanding of the effects of exposure conditions on the character of the cracking produced cannot be too highly emphasized. This is so even if interest is confined solely to simple tests on new protective paints on an acceptance basis rather than research into surface deterioration. It is probable that many protective agencies have been accepted or rejected for extensive production tests because the initial laboratory tests have either not been representative of service or have been inadequate in scope. This still remains a major problem. The theory presented here has gradually taken shape over a period of some ten years and appears to describe adequately the general findings on the whole gamut of cracking, viz., fine check cracking and isolated deep cracks produced under service and laboratory conditions, the latter covering flexing, roof exposure, ozone and similar tests.

Diapause and overwintering of the carrot fly, Psila rosae (F.) (Diptera: Psilidae)

1981 ◽  
Vol 71 (4) ◽  
pp. 583-590 ◽  
Author(s):  
A. J. Burn ◽  
T. H. Coaker
Keyword(s):  
Adult Emergence ◽  
Early Spring ◽  
Pupal Weight ◽  
Prepupal Stage ◽  
Psila Rosae ◽  
Carrot Fly ◽  
Soil Temperatures ◽  
Similar Temperature ◽  
Effects Of Temperature ◽  
Diapause Development

AbstractPsila rosae (F.) overwinters in Britain in both the larval and pupal stages. Overwintering pupae formed in October and November at soil temperatures of between 10 and 16°C entered diapause. A period of similar temperature in the laboratory during the prepupal stage also caused pupae to enter diapause. Overwintering larvae continued to feed and gain weight; they pupated in early spring at soil temperatures of 2–8°C but did not enter diapause. The sensitivity to diapause-inducing conditions decreased between November and March, associated with changes in developmental temperatures and pupal weight. The differential effects of temperature on larval, pupal and diapause development together serve to synchronise adult emergence from the overwintering population. The mechanisms which allow overwintering by a variable proportion of larvae and pupae also provide the opportunity for the development of a third generation of adult flies in October and November.

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