MORTALITY OF WINTER EGGS OF THE EUROPEAN RED MITE PANONYCHUS ULMI (KOCH), AT LOW TEMPERATURES, AND ITS ECOLOGICAL SIGNIFICANCE

1961 ◽  
Vol 39 (3) ◽  
pp. 229-243 ◽  
Author(s):  
A. W. MacPhee
Keyword(s):  
New Brunswick ◽  
Low Temperatures ◽  
Exposure Period ◽  
Panonychus Ulmi ◽  
Winter Mortality ◽  
Ecological Significance ◽  
Recessive Resistance ◽  
Lethal Temperature ◽  
Lethal Temperatures ◽  
The Mean

Winter eggs of the phytophagous mite Panonychus ulmi (Koch) from Nova Scotia were killed by higher temperatures than were eggs from colder areas in New Brunswick and Quebec. For short exposures the mean lethal temperatures were respectively −24° F and −35° F. In the lethal temperature range the mortality of both forms increased about 10% for each doubling of the exposure period in the range from 15 minutes to 16 hours. Reciprocal crosses of the two forms indicated that the factor for resistance to cold in P. ulmi is recessive. Resistance was increased in the laboratory by selection. A method of estimating the winter mortality from weather records is outlined.

scholarly journals Evaluation of an Electrolyte Leakage Technique to Predict St. Augustinegrass Freezing Tolerance

HortScience ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 316-318 ◽  
Author(s):  
F.P. Maier ◽  
N.S. Lang ◽  
J.D. Fry
Keyword(s):  
Freezing Tolerance ◽  
Low Temperatures ◽  
Electrolyte Leakage ◽  
Field Observations ◽  
Lethal Temperature ◽  
Stenotaphrum Secundatum ◽  
Positive Correlation ◽  
Lethal Temperatures ◽  
Lower Lethal Temperature

Stolons of `Raleigh', `Floratam', and FX-332 St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] were sampled from the field between October and March in two consecutive years to evaluate accuracy of an electrolyte leakage (EL) method for predicting freezing tolerance. Lethal temperatures of stolons estimated using EL were compared to those obtained by regrowth tests in the greenhouse. Mean lethal low temperatures for regrowth and EL methods over 12 sampling dates were `Floratam', –4.5C (regrowth) vs. –4.4C (EL); FX-332, –4.2C (regrowth) vs. –4.9C (EL); and `Raleigh', –6.0C (regrowth) vs. –5.4C (EL). A positive correlation (r = 0.81) was observed between EL-predicted and regrowth lethal temperatures for `Raleigh', which exhibited some acclimation during the first sampling year. The EL technique consistently predicted a lower lethal temperature for `Raleigh' than for `Floratam', which corroborates field observations concerning freezing tolerance of these two cultivars.

Upper Lethal Temperatures in Relation to Osmotic Stress in the Ribbed Mussel Modiolus demissus

1971 ◽  
Vol 28 (4) ◽  
pp. 527-532 ◽  
Author(s):  
D. L. Waugh ◽  
E. T. Garside
Keyword(s):  
Osmotic Stress ◽  
Thermal Acclimation ◽  
Test Medium ◽  
Lethal Temperature ◽  
Lethal Temperatures ◽  
Ribbed Mussels ◽  
Osmotic Acclimation ◽  
The Mean ◽  
Ambient Salinity ◽  
Ribbed Mussel

Upper lethal temperatures for the ribbed mussel Modiolus demissus (Dillwyn) were determined for thermal acclimations of 15.0, 20.0, and 25.0 C and osmotic acclimations at 5, 15, and 28‰ S, which yielded nine combinations. These upper lethal temperatures for 1440 min exposure ranged from 38.42 to 40.18 C, generally paralleling increases in thermal acclimation. The upper lethal temperature within any thermal acclimation decreased as the salinity of the bioassay departed from the appropriate level of osmotic acclimation. Depression of the upper lethal temperature was more pronounced in the test medium of 5‰ S. The shift from osmoconformity to osmoregulation, which occurs in this species when the ambient salinity is reduced to 350 mosmols (approximately 10‰ S) apparently extends the metabolic load or stress relative to that induced by similar temperatures in higher levels of salinity. Order of death in any bioassay was independent of size expressed as length, and specific sex.The upper lethal temperatures are higher than the mean temperature of the substrate of the collecting site during the warmest period of the summer, but are approximately the same as the maximum substrate temperature during that period. Survival of ribbed mussels in such potentially lethal conditions is explained by the shorter intermittent natural exposures than those employed in the bioassays.

scholarly journals The Combined Effects of Fine Particulate Matter and Temperature on Preterm Birth in Seoul, 2010–2016

2021 ◽  
Vol 18 (4) ◽  
pp. 1463
Author(s):  
Youngrin Kwag ◽  
Min-ho Kim ◽  
Shinhee Ye ◽  
Jongmin Oh ◽  
Gyeyoon Yim ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Preterm Birth ◽  
Pregnant Women ◽  
Low Temperatures ◽  
Fine Particulate Matter ◽  
Temperature Data ◽  
Fine Particulate ◽  
The Mean ◽  
Pm2.5 Exposure ◽  
Pm2.5 Concentration

Background: Preterm birth contributes to the morbidity and mortality of newborns and infants. Recent studies have shown that maternal exposure to particulate matter and extreme temperatures results in immune dysfunction, which can induce preterm birth. This study aimed to evaluate the association between fine particulate matter (PM2.5) exposure, temperature, and preterm birth in Seoul, Republic of Korea. Methods: We used 2010–2016 birth data from Seoul, obtained from the Korea National Statistical Office Microdata. PM2.5 concentration data from Seoul were generated through the Community Multiscale Air Quality (CMAQ) model. Seoul temperature data were collected from the Korea Meteorological Administration (KMA). The exposure period of PM2.5 and temperature were divided into the first (TR1), second (TR2), and third (TR3) trimesters of pregnancy. The mean PM2.5 concentration was used in units of ×10 µg/m3 and the mean temperature was divided into four categories based on quartiles. Logistic regression analyses were performed to evaluate the association between PM2.5 exposure and preterm birth, as well as the combined effects of PM2.5 exposure and temperature on preterm birth. Result: In a model that includes three trimesters of PM2.5 and temperature data as exposures, which assumes an interaction between PM2.5 and temperature in each trimester, the risk of preterm birth was positively associated with TR1 PM2.5 exposure among pregnant women exposed to relatively low mean temperatures (<3.4 °C) during TR1 (OR 1.134, 95% CI 1.061–1.213, p < 0.001). Conclusions: When we assumed the interaction between PM2.5 exposure and temperature exposure, PM2.5 exposure during TR1 increased the risk of preterm birth among pregnant women exposed to low temperatures during TR1. Pregnant women should be aware of the risk associated with combined exposure to particulate matter and low temperatures during TR1 to prevent preterm birth.

scholarly journals In-Furrow Applications of Metalaxyl and Phosphite for Control of Pink Rot (Phytophthora erythroseptica) of Potato in New Brunswick, Canada

Plant Disease ◽  
2007 ◽  
Vol 91 (10) ◽  
pp. 1305-1309 ◽  
Author(s):  
Khalil I. Al-Mughrabi ◽  
Rick D. Peters ◽  
H. W. (Bud) Platt ◽  
Gilles Moreau ◽  
Appanna Vikram ◽  
...  
Keyword(s):  
New Brunswick ◽  
Disease Incidence ◽  
Field Trials ◽  
Russet Burbank ◽  
Viable Option ◽  
Potato Plants ◽  
Pink Rot ◽  
Phytophthora Erythroseptica ◽  
Sensitive Isolate ◽  
The Mean

The efficacy of metalaxyl-m (Ridomil Gold 480EC) and phosphite (Phostrol) applied at planting in-furrow against pink rot (Phytophthora erythroseptica) of potato (Solanum tuberosum) ‘Shepody’ and ‘Russet Burbank’ was evaluated in field trials conducted in 2005 and 2006 in Florenceville, New Brunswick, Canada. Inoculum made from a metalaxyl-m-sensitive isolate of P. erythroseptica from New Brunswick was applied either in-furrow as a vermiculite slurry at planting or as a zoospore drench in soils adjacent to potato plants in late August. After harvest, the number and weight of tubers showing pink rot symptoms were assessed and expressed as percentages of the total tuber number and total weight of tubers. Metalaxyl-m applied in-furrow was significantly more effective against pink rot than phosphite. The mean percentage of diseased tubers as a percentage of total tuber weight was 1.5% (2005) and 1.2% (2006) for metalaxyl-m-treated plots and 9.6% (2005) and 2.8% (2006) for phosphite-treated plots, a percentage similar to that obtained in inoculated control plots with no fungicide treatment. The mean percentage of diseased tubers expressed as a percentage of the total number of tubers was 1.7% (2005) and 1.3% (2006) for metalaxyl-m-treated plots and 10.1% (2005) and 3.1% (2006) for phosphite-treated plots. Disease incidence was significantly higher using the late-season inoculation technique (respective means in 2005 and 2006 were 9.9 and 3.8% diseased tubers, by weight, and 10.6 and 3.9%, by number) than with the in-furrow inoculation method (respective means in 2005 and 2006 were 3.3 and 0.7% by weight, and 3.7 and 1.3%, by number). The potato cv. Shepody was significantly more susceptible to pink rot (9.9 and 3.3% diseased tubers, by weight, in 2005 and 2006, respectively, and 10.6 and 3.9%, by number) than Russet Burbank (respective means in 2005 and 2006 were 3.4,% and 1.2%, by weight, and 3.7,% and 1.2%, by number). Our findings indicate that metalaxyl applied in-furrow at planting is a viable option for control of pink rot caused by metalaxyl-sensitive strains of P. erythroseptica, whereas phosphite was ineffective.

SOME LETHAL TEMPERATURE RELATIONS OF TWO MINNOWS OF THE GENUS CHROSOMUS

1966 ◽  
Vol 44 (3) ◽  
pp. 349-364 ◽  
Author(s):  
Albert V. Tyler
Keyword(s):  
Thermal Shock ◽  
High Temperatures ◽  
The Other ◽  
Lethal Temperature ◽  
Lethal Temperatures ◽  
Equal Temperature

The resistance and tolerance of Chrosomus eos and Chrosomus neogaeus to high temperatures were examined. Tests were conducted with C. neogaeus in winter and with C. eos in winter and summer. For both species, death at high temperatures could be separated into three lethal patterns or "effects". The first effect seemed to be associated, at least in part, with thermal shock. Factors generating the other effects were not apparent.Both species showed about the same degree of tolerance and resistance to high temperatures when they were acclimated to 15 °C or higher. At 9 °C, C. eos was less tolerant to high lethal temperatures than was C. neogaeus.When equal temperature acclimations were compared, C. eos was more resistant to high lethal temperatures in summer than in winter.

PREDATION BY INSECTS AND SPIDERS INHABITING COLONIAL WEBS OF HYPHANTRIA CUNEA

1972 ◽  
Vol 104 (8) ◽  
pp. 1197-1207 ◽  
Author(s):  
R. F. Morris
Keyword(s):  
Population Dynamics ◽  
Nova Scotia ◽  
North America ◽  
Population Density ◽  
New Brunswick ◽  
Numerical Response ◽  
Initial Number ◽  
Hyphantria Cunea ◽  
The North ◽  
The Mean

AbstractThe number of predators inhabiting nests of Hyphantria cunea Drury was recorded annually for 13 years in four areas in New Brunswick and two areas on the coast of Nova Scotia. The most common groups were the pentatomids and spiders, which sometimes reproduced within the nests, but the mean number per nest was low in relation to the number of H. cunea larvae in the colonies. The rate of predation on fifth-instar larvae was low. Small or timid predators appeared to prey largely on moribund larvae or small saprophagans during the principal defoliating instars of H. cunea.No relationship could be detected between the number of larvae reaching the fifth instar and the number of predators in the colony; nor could any functional or numerical response of the predators to either the initial number of larvae per colony or the population density of colonies be found. It is concluded that the influence of the nest-inhabiting predators is small and relatively stable, and may be treated as a constant in the development of models to explain the population dynamics of H. cunea.H. cunea is a pest in parts of Europe and Asia, where it has been accidentally introduced from North America. The introduction to other continents of the North American predator, Podisus maculiventiis (Say), is discussed briefly.

BIOCONTROL OF THE WEED CANADA THISTLE (CIRSIUM ARVENSE): RELEASES AND DEVELOPMENT OF THE GALL FLY UROPHORA CARDUI (DIPTERA: TEPHRITIDAE) IN CANADA

1982 ◽  
Vol 114 (4) ◽  
pp. 349-357 ◽  
Author(s):  
D. P. Peschken ◽  
D. B. Finnamore ◽  
A. K. Watson
Keyword(s):  
New Brunswick ◽  
Cirsium Arvense ◽  
Winter Mortality ◽  
Western Canada ◽  
Canada Thistle ◽  
Main Shoot ◽  
The West ◽  
The Impact

AbstractThe gall fly Urophora cardui (L.) (Diptera: Tephritidae), native to Europe, was released at 24 locations across Canada beginning in 1974. It became established in Ontario, Quebec, and New Brunswick but died out in all but one location in western Canada. Evidence for winter mortality in the west does not explain the failure of these colonies. Although galls, in particular those on the main shoot, reduce the height of Canada thistle, so far the impact on the host weed, Canada thistle (Cirsium arvense) (L.) Scop., is slight.

scholarly journals Reproduction and feeding of Sagitta enflata in the Humboldt Current system off Chile

2008 ◽  
Vol 65 (3) ◽  
pp. 361-370 ◽  
Author(s):  
Ricardo Giesecke ◽  
Humberto E. González
Keyword(s):  
Feeding Rate ◽  
Current System ◽  
Zooplankton Abundance ◽  
Daily Ration ◽  
Ecological Significance ◽  
Prey Selectivity ◽  
Humboldt Current ◽  
The Mean ◽  
Humboldt Current System ◽  
Paracalanus Parvus

Abstract Giesecke, R., and González, H. E. 2008. Reproduction and feeding of Sagitta enflata in the Humboldt Current system off Chile. – ICES Journal of Marine Science, 65: 361–370. This study is based on 3 years (August 2002–July 2005) of monthly zooplankton sampling at a fixed station located 18 km off Coliumo Bay (36°S), Chile. The reproduction of Sagitta enflata, its feeding rate, specific daily ration, and prey selectivity were analysed and related to several environmental variables: temperature, salinity, dissolved oxygen, chlorophyll a concentrations, and both meso- and micro-zooplankton abundance. The main predatory activity of S. enflata was centred on the copepods Paracalanus parvus, Oithona spp., and Calanus chilensis. These three species were consumed at different rates, depending mainly on the maturity of the S. enflata population. When Stages I and II individuals dominated, predation focused on the small P. parvus and Oithona spp., whereas more mature populations (Stages III and IV) preyed selectively on C. chilensis. The mean specific daily ration of 0.1 d−1 increased to 0.5 d−1 before and during maturation. The reproductive phase of S. enflata was closely coupled with the abundance of nauplii, suggesting that chaetognath reproduction paralleled that of copepods, most likely to diminish the mortality of its offspring resulting from starvation. The relationships between these were included in a conceptual model and their ecological significance is discussed.

Effect of seed size on germination in three species from arid Arabian deserts

Botany ◽  
2020 ◽  
Author(s):  
Sanjay Gairola ◽  
Tamer Mahmoud ◽  
Hatem A. Shabana ◽  
Asma AlKetbi ◽  
Shyam Phartyal
Keyword(s):  
Seed Size ◽  
Low Temperatures ◽  
Germination Percentage ◽  
Light Regime ◽  
Salvadora Persica ◽  
Large Size ◽  
Significant Difference ◽  
Brassica Tournefortii ◽  
The Mean ◽  
Study Species

In many species, seeds with different sizes show diverse responses in their requirements for temperature and light for optimal germination. In this study, the effect of seed size (i.e., small and large) on germination was tested in seeds of Brassica tournefortii Gouan., Lotus garcinii DC., and Salvadora persica L. from arid Arabian Desert habitats. The mean seed size of all three study species differs significantly between small and large-sized seeds. Differences were observed in seed germination between large and small seeds of B. tournefortii and L. garcinii. We found that large-size seeds of B. tournefortii and L. garcinii showed higher germination at all tested temperatures than that displayed by small-sized seeds. However, both small and large seeds of S. persica germinated equally (100%) well under all incubated conditions. Our results show significant differences in germination percentage between small and large-sized seeds of B. tournefortii at 25/35°C under a 12-hour light regime. However, L. garcinii has a significant difference in germination percentage at low temperatures (15/25°C) under a 12-hour light regime.

Temperature Tolerance of Bloater (Coregonus hoyi)

1970 ◽  
Vol 27 (11) ◽  
pp. 2047-2052 ◽  
Author(s):  
Thomas A. Edsall ◽  
Donald V. Rottiers ◽  
Edward H. Brown
Keyword(s):  
Young Adult ◽  
High Temperatures ◽  
Thermal Tolerance ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Temperature Tolerance ◽  
Lethal Temperature ◽  
Lethal Temperatures ◽  
Coregonus Artedii ◽  
Coregonus Hoyi

Juvenile and young adult bloaters (Coregonus hoyi) were tested for tolerance to high temperatures. The ultimate upper lethal temperature of juvenile bloaters (26.75 C) appeared to be slightly higher than that of young adult bloaters, but was similar to that of juvenile ciscoes, Coregonus artedii (26.0 C), the only other North American coregonine for which a detailed description of temperature tolerance has been published.Regression equations are given that permit estimation of the thermal tolerance when the lethal temperatures are incompletely known. The estimated thermal tolerance of juvenile bloaters (617 units) was slightly less than that of the brook trout (Salvelinus fontinalis; 625 units), but was higher than that of other Salmonidae.

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