Spruce Budworm Parasite Studies in Northwestern Ontario

1959 ◽  
Vol 91 (12) ◽  
pp. 758-783 ◽  
Author(s):  
B. M. McGugan ◽  
J. R. Blais
Keyword(s):  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Senior Author ◽  
The West ◽  
Northwestern Ontario ◽  
Junior Author ◽  
Limited Basis ◽  
The University ◽  
Parasite Complex ◽  
General Influence

The extensive coniferous stands in northwestern Ontario have been subjected to repeated widespread outbreaks of the spruce budworm, Choristoneura fumiferana (Clem.) (5). About 1939 two such outbreaks originated almost simultaneously, one on the west shores of Lake Nipigon and the other south of Lac Seul approximately 180 miles farther west. Each outbreak eventually covered thousands of square miles and was responsible for the destruction of hundreds of square miles of balsam fir forest. Studies of the parasite complex attacking the spruce budworm in northwestern Ontario and the assessment of its general influence on budworm population trends were initiated in the Lake Nipigon outbreak in 1946 by Professor N. R. Brown, now of the University of New Brunswick, and were further developed by the senior author from 1947 to 1950. Similar investigations were initiated by the junior author in the Lac Seul outbreak in 1950 and continued until 1954. Studies in both areas were continued on a limited basis until 1956 through the co-operation of several research officers.

A Relation Between April and May Temperatures and Spruce Budworm Larval Emergence

1954 ◽  
Vol 86 (4) ◽  
pp. 174-177 ◽  
Author(s):  
A. H. Rose ◽  
J. R. Blais
Keyword(s):  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Apparent Temperature ◽  
Temperature Threshold ◽  
Northwestern Ontario ◽  
Large Numbers ◽  
Larval Emergence ◽  
Sudden Appearance ◽  
Spring Temperatures ◽  
Four Square

In the spring, spruce budworm (Choristoneura fumiferana (Clem)), emerge as second-instar larvae from hibernacula. This emergence may be sudden and is readily detectable in the field. In northwestern Ontario, the sudden appearance of larvae in large numbers was especially spectacular in 1948; that year, very few insects were observed on May 11, but on the following two days, countless larvae could be seen on strands of silk streaming out from trees. Many of the insects were carried away by air currents. The surface of Big Canon Lake, a body of water close to four square miles in area, was covered with larvae, at an estimated density of 100 larvae per square foot of surface. At other times, however, emergence may be gradual or there may be two distinct periods of abundant emergence. Furthermore, the time of abundant larval emergence through six years has varied by as much as four weeks. Because of such differences, prevailing spring temperatures were examined to determine what relationship might exist between temperature and the time and character of emergence. This paper points out a relationship between emergence and April and May temperatures, and an apparent temperature threshold for emergence.

Notes on the Biology of Synetaeris tenuifemur Walley (Hymenoptera: Ichneumonidae)

1963 ◽  
Vol 95 (1) ◽  
pp. 24-28 ◽  
Author(s):  
C. A. Miller ◽  
T. R. Renault
Keyword(s):  
British Columbia ◽  
New Brunswick ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Green River ◽  
Low Level ◽  
Northwestern Ontario ◽  
North Western

The species discussed below was first recorded under the name Synetaeris n. sp. as a parasite of the spruce budworm, Choristoneura fumiferana Clem., in Ontario by McGugan and Blais (1959), although they point out that it may have been collected from budworm in British Columbia during the 1940's but incorrectly identified at that time. These authors collected S. tenuifemur during the declining years of a budworm outbreak in the Lake Nipigon region of northwestern Ontario, and it was during the declining years of a severe outbreak that the parasite was first reared from budworm in the Green River area of north-western New Brunswick (Morris, 1963, in press). These data suggest that S. tenuifemur is associated with endemic budworm populations, an assumption advanced by McGugan and Blais (1959). However, it was not found in the Green River area from 1945 to 1947 when budworm density was at a low level prior to the 1949-1959 outbreak.

Death and Deterioration of Balsam Fir Weakened by Spruce Budworm Defoliation in Ontario: Part I Notes on the seasonal history and habits of insects breeding in severely weakened and dead trees

1952 ◽  
Vol 84 (11) ◽  
pp. 325-335 ◽  
Author(s):  
R. M. Belyea
Keyword(s):  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Intensive Study ◽  
Northwestern Ontario ◽  
Host Trees ◽  
Dead Trees ◽  
Seasonal History

One of the problems arising from severe outbreaks of the spruce budworm, Choristoneura fumiferana (Clem.), is the evaluation of the factors contributing to the decline of the host trees. An intensive study of the death and deterioration of balsam fir, Abies balsamea (L.) Mill., was carried out from 1946 to 1951 in the area southwest of Lake Nipigon in northwestern Ontario, where a severe spruce budworm outbreak was in progress.

MONITORING SPRUCE BUDWORM POPULATION DENSITY WITH SEX PHEROMONE TRAPS

1988 ◽  
Vol 120 (2) ◽  
pp. 175-183 ◽  
Author(s):  
C.J. Sanders
Keyword(s):  
Sex Pheromone ◽  
Population Density ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Pheromone Traps ◽  
Cooperative Research ◽  
Population Densities ◽  
Larval Population ◽  
Northwestern Ontario ◽  
Sex Pheromone Traps

AbstractAnnual catches of male spruce budworm (Choristoneura fumiferana [Clem.]) in sex pheromone traps over a 21-year period in northwestern Ontario were well correlated with larval population densities in each subsequent year (r2 = 81%). On the basis of the criterion of 3 successive years of increasing catches or a threshold of 50 moths per trap, warning of extensive defoliation could have been given 6 years in advance. In 18 plots in northwestern Ontario and 35 plots distributed throughout the province, coefficients of determination (r2) between catch and population density in the same generation ranged from 40 to 74% in 1982 and 1983, but fell below 23% in 1984 when population densities in many plots were high. Coefficients of determination between catch and population densities in the following generation (eggs or larvae) ranged from 41 to 62%. On the basis of several years of cooperative research, sex pheromone traps are now in operational use in eastern North America for monitoring spruce budworm populations.

CARPENTER ANTS AS PREDATORS OF SPRUCE BUDWORM IN THE BOREAL FOREST OF NORTHWESTERN ONTARIO

1992 ◽  
Vol 124 (6) ◽  
pp. 1093-1100 ◽  
Author(s):  
C.J. Sanders ◽  
A. Pang
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Western North America ◽  
Tree Crown ◽  
Carpenter Ants ◽  
Northwestern Ontario ◽  
Large Numbers ◽  
Laboratory Colony

AbstractIn the boreal forest of northwestern Ontario, where carpenter ants (Camponotus spp.) construct extensive underground tunnels, few worker ants were seen on the aerial portions of trees containing colonies of the ants or on neighboring trees, even though the trees were infested by large numbers of spruce budworm [Choristoneura fumiferana (Clem.)] larvae. Immunochemical techniques detected less spruce budworm soluble protein in worker ants from this area than in a laboratory colony that had been fed budworm larvae, or in a colony located in a spruce tree that was surrounded by gravel where the ants were unable to build underground tunnels and instead foraged extensively in the tree crown. This suggests that, in contrast to evidence from western North America, carpenter ants in the boreal forests of northwestern Ontario, and perhaps elsewhere throughout the range of the spruce budworm, are of limited importance as predators of the spruce budworm.

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.

Cotton Textile and Leather Exports: What Cost Foreign Exchange? (Notes & Comments)

1969 ◽  
Vol 9 (3) ◽  
pp. 330-342
Author(s):  
G. C. Hufbauer ◽  
Nayyara Aziz ◽  
Asghar Ali
Keyword(s):  
Foreign Exchange ◽  
Senior Author ◽  
Cotton Textile ◽  
The West ◽  
Cotton Textiles ◽  
Economic Inquiry ◽  
Manufactured Goods ◽  
The Relationship ◽  
Development Department

The senior author has elsewhere argued [8] that foreign exchange earned by the export of West Pakistan-manufactured goods has a high domestic cost. Much the same contention has been advanced by Hecox [7], Islam [9] and MacEwan [11]. In these papers the relationship between costs and earnings is usually based on fairly abstract assumptions. The purpose of this note is to reduce the calculations to a "plain man" level. Specifically, we try to calculate how many rupees of indigenous resources are expended to earn each extra rupee of foreign exchange which is received from exporting cotton textiles and leather goods rather than their primary ingredients, namely raw cotton and hides and skins i. Since this note was written, the Board of Economic Inquiry, Lahore, at the request of the West Pakistan Planning and Development Department, has undertaken a wider study applying the same general approach used here.

Derivation of Pheromone-Based Larval Thresholds in Spruce Budworm Accounting for Distance to Defoliated Forest Stands

2021 ◽  
Author(s):  
Marc Rhainds ◽  
Ian DeMerchant ◽  
Pierre Therrien
Keyword(s):  
Boreal Forests ◽  
Large Scale ◽  
Choristoneura Fumiferana ◽  
Intervention Strategy ◽  
Spruce Budworm ◽  
Interactive Effects ◽  
The Novel ◽  
Forest Stands ◽  
General Guideline ◽  
Number Of Males

Abstract Spruce budworm, Choristoneura fumiferana Clem. (Lepidoptera: Tortricidae), is the most severe defoliator of Pinaceae in Nearctic boreal forests. Three tools widely used to guide large-scale management decisions (year-to-year defoliation maps; density of overwintering second instars [L2]; number of males at pheromone traps) were integrated to derive pheromone-based thresholds corresponding to specific intergenerational transitions in larval densities (L2i → L2i+1), taking into account the novel finding that threshold estimates decline with distance to defoliated forest stands (DIST). Estimates of thresholds were highly variable between years, both numerically and in terms of interactive effects of L2i and DIST, which limit their heuristic value. In the context of early intervention strategy (L2i+1 > 6.5 individuals per branch), however, thresholds fluctuated within relatively narrow intervals across wide ranges of L2i and DIST, and values of 40–200 males per trap may thus be used as general guideline.

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