Parasite Studies in Two Residual Spruce Budworm (Choristoneura fumiferana (Clem.)) Outbreaks in Quebec

1965 ◽  
Vol 97 (2) ◽  
pp. 129-136 ◽  
Author(s):  
J. R. Blais
Keyword(s):  
Relative Abundance ◽  
Parasite Species ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Insect Population ◽  
The Other ◽  
Aerial Application ◽  
The One ◽  
Parasite Complex ◽  
Very High

AbstractParasite studies were carried out in two residual spruce budworm outbreaks in Quebec. Investigations were conducted during the last three years of the outbreak in the Lower St. Lawrence region and during the last year of the one in the Saguenay region. In the Lower St. Lawrence region decline of the insect population was initiated through aerial application of DDT over a period of three years, while in the Saguenay region the unfavourable condition of the forest stands apparently kept budworm numbers below peak outbreak levels. The incidence of mortality through the action of parasites was very high during the last year of both of these outbreaks and probably contributed to bringing about their collapse. Meteorus trachynotus Vier. has repeatedly been recovered in abundance during the last year of a number of budworm outbreaks and it was amongst the important parasites recovered in both outbreaks under discussion. Other species, however, that were abundant in one or the other of these two outbreaks had not been recovered in numbers before. The parasite complex and the relative abundance of each parasite species during budworm outbreaks is fairly constant at the time of peak host populations, but it is now apparent that they vary considerably at the time of outbreak collapse. Variations in the presence and relative abundance of alternate hosts probably account for this situation.

Bit Swap Established on EOC for VDSL

2014 ◽  
Vol 513-517 ◽  
pp. 1170-1175
Author(s):  
Chen En Liu ◽  
Ping Li
Keyword(s):  
Rapid Development ◽  
The Other ◽  
Test Results ◽  
Digital Subscriber Line ◽  
Crosstalk Noise ◽  
Line System ◽  
Subscriber Line ◽  
High Bit Rate ◽  
The One ◽  
Very High

With the rapid development of VDSL (Very high-bit-rate Digital Subscriber Line) system, not all the tones have the same margin. In order to cope with the slowly-changing channel, Bit Swap is utilized to swap the tone pairs: the one has a high margin while the other one has a relatively low margin. Although the Bit Swap has been proposed before, there is no Bit Swap established on EOC and the proposed scheme also implements coarse and fine SNR margin tuning. The paper presents the architecture and process of Bit Swap based on EOC and also proposes the method to adjust the margin for tones calculated to be swapped. After thoroughly tested, the test results show that the proposed scheme functions well. Compared with the scheme without Bit Swap, it greatly improves the performance against crosstalk noise and can reduce the RS errors to zero.

Effets de la coupe à blanc et de la coupe par bandes sur la régénération obtenue après 5 ans dans des pessières noires du Québec

1995 ◽  
Vol 25 (2) ◽  
pp. 329-342 ◽  
Author(s):  
Pierre Pominville ◽  
Jean-Claude Ruel
Keyword(s):  
Black Spruce ◽  
Spruce Budworm ◽  
Lower Proportion ◽  
The Other ◽  
Balsam Fir ◽  
Clear Cutting ◽  
Other Hand ◽  
The One ◽  
Almost All ◽  
Coupe À Blanc

An experiment was conducted to compare the effects of traditional clear-cutting with those of strip cutting on regeneration of black spruce, Piceamariana (Mill.) B.S.P., stands on scarified and unscarified uplands and on lowlands. To that effect, regeneration surveys were done before cutting, in the following year, and 3 and 5 years after cutting. Five years after harvesting, strip cutting led to higher coniferous stocking than clear-cutting on scarified uplands and on lowlands. On unscarified uplands, the gain attributable to strip cutting was not significant. The coniferous stocking of strip cuts on scarified uplands was not greater than on unscarified uplands. So the efficiency of scarification could not be proved in that study. Stocking obtained after 5 years remained closely related to the one observed immediately after harvesting in the strip cufs as in the clear-cuttings. This is particularly true for balsam fir, Abiesbalsamea (L.) Mill. In the strip cuts, the balsam fir stocking was constant while the one of black spruce increased. This could have an impact on the evolution of the composition of the new stands and, consequently, on their vulnerability to spruce budworm, Choristoneurafumiferana (Clem.). The majority of the clear-cuttings were well regenerated 5 years after harvesting. Their average coniferous stocking was slightly above 60%. However, 48% of the clear-cuttings did not reach this level when only unscarified plots on uplands were considered. Advance growth was abundant in those plots but suffered high losses during harvesting. Consequently, reducing the losses during harvesting would result in a lower proportion of clear-cuttings with insufficient coniferous stocking 5 years after cutting. On the other hand, almost all the strip cuts with insufficient regeneration after harvesting were well regenerated 5 years later. Thus, strip cutting could be an interesting option on sites with insufficient advance growth and on sites well regenerated before cutting but where important losses during harvesting are anticipated.

EFFECTS OF BLENDS OF SEX PHEROMONE ISOMERS ON MATING AND ELECTROANTENNOGRAMS OF SPRUCE BUDWORM (LEPIDOPTERA: TORTRICIDAE)

1982 ◽  
Vol 114 (12) ◽  
pp. 1143-1149 ◽  
Author(s):  
R. J. Ross ◽  
W. D. Seabrook ◽  
G. C. Lonergan ◽  
P. Palaniswamy ◽  
B. Ponder
Keyword(s):  
Sex Pheromone ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
The Other ◽  
Conifer Forest ◽  
Male And Female ◽  
A Current ◽  
Female Laboratory

AbstractMale and female laboratory reared spruce budworm moths, Choristoneura fumiferana (Clem.), were placed in cages in a conifer forest, and the surrounding air permeated by each of four blends of the E and Z isomers of the sex pheromone (11-tetradecenal) at two concentrations. Mating suppression of 53–83% was found for each blend tested. At one concentration the four suppressions were similar, while at the other only one was significantly different. Electroantennograms (EAGs) were obtained from male moths for each of six E:Z blends at four concentrations. EAGs were similar for most blends at a given concentration, but tended to be larger than at a blend of 0E:100Z.These results were discussed using a current hypothesis on the ability of males to detect sex pheromone in air containing pockets of different isomeric blends.

Laying Eggs at High Altitude

Physiology ◽  
1988 ◽  
Vol 3 (2) ◽  
pp. 69-71 ◽  
Author(s):  
CC Monge ◽  
F Leon-Velarde ◽  
G Gomez de la Torre
Keyword(s):  
High Altitude ◽  
Water Loss ◽  
Oxygen Supply ◽  
The Other ◽  
High Altitudes ◽  
High Mountains ◽  
The One ◽  
Very High

The hypoxic and dry environment of the high mountains seems to select eggshells with porosities appropriate for the altitudinal level. At moderate altitudes, the conservation of water takes precedence over the oxygen-supply gradient. At very high altitudes there is a compromise between reducing water loss on the one hand and the defense of the oxygen supply to the embryo on the other.

Dynamique de la sapinière à bouleau jaune de l'est après une épidémie de tordeuse des bourgeons de l'épinette

1999 ◽  
Vol 75 (3) ◽  
pp. 515-534 ◽  
Author(s):  
Pierre Pominville ◽  
Stéphane Déry ◽  
Louis Bélanger
Keyword(s):  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
The Other ◽  
Balsam Fir ◽  
Betula Alleghaniensis ◽  
White Birch ◽  
Yellow Birch ◽  
Mixed Stands ◽  
The Dead

An outbreak of spruce budworm, Choristoneura fumiferana (Clem.), occurred between 1974 and 1987, in Quebec, in the eastern balsam fir, Abies balsamea (L.) Mill, - yellow birch, Betula alleghaniensis Britton, ecoclimatic sub-domain. The effect of this disruption has been assessed in mesic balsam fir stands killed during the outbreak, in mesic balsam fir stands partially damaged and in the following stands, also partially damaged: mesic yellow birch – balsam fir stands, mesic white birch, Betulapapyrifera Marsh., - balsam fir stands, mesic balsam fir – yellow birch stands, mesic balsam fir – white birch stands and xeric balsam fir stands. To that effect, surveys were led before, immediately after, and about five years after the outbreak in two blocks that have not been protected with insecticides. These blocks, located in Charlevoix and in Shipshaw management units, are second growth stands originating from clearcuts which occured about 50 years ago. Approximately five years after the outbreak, abundant coniferous regeneration was found everywhere except in the mesic yellow birch –balsam fir stand and in the dead mesic balsam fir stand, where softwood represented less than 50% of the regeneration. On the other hand, young softwood stems were located under the regeneration of white birch and of mountain maple, Acer spicatum Lam, in dead balsam fir stands, in balsam fir – white birch stands, as well as in living balsam fir stands and under mountain maple in yellow birch – balsam fir stands and in balsam fir – yellow birch stands. Our age structures indicate that softwood advance growth was relatively rare in these stands. Thus, during the opening of the canopy by the spruce budworm, intolerant hard-woods and shrubs invaded the still available microsites. In the dead balsam fir stands, stocking of the dominant hardwood regeneration stems is equivalent to that of softwood. Thus, dead balsam fir stands are turning to mixed stands. Xeric stands will remain softwood stands since they show luxuriant softwood regeneration dominating in height. In the other stands, we will have to wait the harvest period before we can adequately assess succession.

scholarly journals On a Consistent Definition of Intensive Use of a Resource

1979 ◽  
Vol 8 (1) ◽  
pp. 52-53
Author(s):  
Pritam S. Dhillon
Keyword(s):  
Beginning Teachers ◽  
Relative Abundance ◽  
The Other ◽  
Other Hand ◽  
Intensive Use ◽  
Teachers And Students ◽  
The One ◽  
Definition Of

It would seem, for the sake of convenience and in the interest of imparting exact information, that the terms used in a discipline should have one and only one meaning. Unfortunately economics terminology is not in such a completely refined state that all terms have unambiguous meanings. In some instances different meanings are attached to the same terms which is a source of confusion. This is especially the case for the term “intensive” use of a resource which frequently has been used to describe the relative abundance of a resource in production. The term has been used inconsistently in two opposing senses when applied to land and labor on the one hand and capital and labor on the other hand. While this may not pose a serious problem for a seasoned scholar who can construe the proper meaning in each context, beginning teachers and students need to be made aware of the inconsistency to avoid confusion and unnecessary debate.

SOME RELATIONSHIPS OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.) TO BLACK SPRUCE, PICEA MARIANA (MOENCH) VOSS

1957 ◽  
Vol 33 (4) ◽  
pp. 364-372 ◽  
Author(s):  
J. R. Blais
Keyword(s):  
Picea Mariana ◽  
Nutritional Quality ◽  
Black Spruce ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
The Other ◽  
Rate Of Development ◽  
The Third ◽  
Adequate Food

Spruce budworm larvae feeding on black spruce had a lower rate of development and a higher rate of mortality than those feeding on white spruce or balsam fir. This was attributable to the lateness in opening of the black spruce buds rather than to the inferior nutritional quality of the foliage. When staminate flowers were present in abundance on black spruce trees, development and survival of the insect was fairly similar to that on the other two species of trees; the flowers provided adequate food at the time of the third and fourth instars thus permitting the larvae to survive until the opening of the shoot buds. The late opening of the black spruce buds explains the relative immunity of this species to severe spruce budworm damage.

VIII. On the structure and development of the skull in the ostrich tribe

1866 ◽  
Vol 156 ◽  
pp. 113-183 ◽  
Keyword(s):  
The Other ◽  
The One ◽  
High Degree ◽  
Very High

T he present paper is intended to be the first of a series on the Anatomy of the Vertebrate Skull; and I have chosen the cranium and face of the Ostriches as a startingpoint, principally because of the mid position of these birds in the vertebrate subkingdom, and, in some degree also, because of their generalized character. Indeed, to any one familiar, on the one hand, with the structure of the skull in the higher mammalian types, and on the other with that of the osseous fishes, the skull of an Ostrich is interesting and important in a very high degree; serving, at it does, as a key to open up the meaning of parts so extremely unlike as the true homologues in the Fish and in the Mammal often are. And further, whilst aiding the anatomist in revealing the true morphological counterparts in the highest, as compared with the lowest types, the skull of an ostrich does also form a link of the utmost value for connecting together that of a cold-blooded and that of a warm-blooded creature.

Première of films arranged by the Shell International Petroleum Company

1961 ◽  
Vol 16 (1) ◽  
pp. 93-94
Keyword(s):  
Natural Science ◽  
Royal Society ◽  
The Other ◽  
High Quality ◽  
Natural Knowledge ◽  
Royal Dutch Shell ◽  
The One ◽  
Petroleum Company ◽  
Very High

On the afternoon of Friday 22 July, a premiere of films was given at the Royal Festival Hall and was followed by a Reception at Tea when Mr F. J. Stephens acted as host for the Royal Dutch/Shell Group of Companies. The programme was introduced by Sir Cyril Flinshelwood, President of the Royal Society, who said: . ‘In the Charter of the Royal Society the improvement of natural knowledge is coupled with that of the useful arts. Now the tradition fortunately exists in this country of good relations between the great industries on the one hand and the cultivators of natural science on the other: or I would prefer to say the very nebulous line that there is between these two branches of activity is evidence of the fact that this part of the Charter has in fact not been ignored. That the Shell Group of Companies, one of the greatest and most important, has made the extremely generous gesture of preparing the very splendid film that you will presently see in honour of the Tercentenary of the Royal Society proves that the tradition that I have spoken of is alive and vigorous. ‘You will presently agree that the film also demonstrates the very high quality of the Film Unit which the Company has maintained for, I understand, something over a quarter of a century.

NOTES ON THE EFFECTS OF PHYSICAL FACTORS ON THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.)

1947 ◽  
Vol 79 (11-12) ◽  
pp. 195-195 ◽  
Author(s):  
W. G. Wellington ◽  
W. R. Henson
Keyword(s):  
Light Intensity ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
The Other ◽  
Negative Response ◽  
Physical Factors ◽  
Light Traps ◽  
Compass Orientation ◽  
Orderly Transition

Concerning the light reactions of the adults, it may be noted that males are photopositive when in a dark-adapted state, but they rapidly become adapted to any light intensity and become extremely sluggish. Females in the dark-adapted state exbihit either photonegative behaviour or compassing behaviour, with no evidence that there is any orderly transition from one type of behaviour to the other. Light-compass orientation of flying females makes it possible to collect some at light traps, despite their normally negative response.

Sign in / Sign up

Export Citation Format

Share Document