scholarly journals A RECENT SPRUCE BUDWORM OUTBREAK IN THE LOWER ST. LAWRENCE AND GASPE PENINSULA WITH REFERENCE TO AERIAL SPRAYING OPERATIONS

1960 ◽  
Vol 36 (3) ◽  
pp. 209-224 ◽  
Author(s):  
J. R. Blais ◽  
R. Martineau

The main topics discussed in this paper are: the progress of the spruce budworm outbreak in the Lower St. Lawrence - Gaspé regions from 1949 to 1956; the areas sprayed between 1954 and 1958; timing of spray application in relation to insect abundance and development; effects of treatment on spruce budworm populations and on defoliation of balsam fir; results of aerial defoliation surveys and egg surveys; estimated amounts of wood destroyed by the insect, and losses averted through spraying; the various natural control factors associated with the decline and the eventual collapse of the outbreak.

1963 ◽  
Vol 95 (8) ◽  
pp. 821-827 ◽  
Author(s):  
J. R. Blais

AbstractAn attempt was made to suppress an incipient spruce budworm outbreak in the Lower St. Lawrence region of Quebec through the aerial application of DDT. Operations began in 1960 and continued in 1961 and 1962 when they finally met with success. Failure to achieve success earlier was due partly to the exceptionally favourable survival conditions for the insect in 1960, and partly to the inadvertent omission of a small infested area from the program in 1961. The operations greatly reduced spruce budworm populations each year in the outbreak area, while the action of natural control factors, including parasites and predators increased. The collapse of the outbreak was the result of the combined effects of the chemical treatments and of natural control factors.


1961 ◽  
Vol 93 (2) ◽  
pp. 118-123 ◽  
Author(s):  
J. G. Pilon ◽  
J. R. Blais

Nearly all forest regions in the Province of Quebec where balsam fir (Abies balsamea (L.) Mill.) is an important tree component have been subjected to severe defoliation by the spruce budworm, Choristoneura fumiferana (Clem.), during the past 20 years. These outbreaks have followed an easterly direction beginning near the Ontario-Quebec border in 1939 and ending in the Gaspé Peninsula in 1958.


1961 ◽  
Vol 37 (3) ◽  
pp. 203-210 ◽  
Author(s):  
J. R. Blais

The aerial application of insecticides against spruce budworm outbreaks is now a common practice. The measure had always been applied in outbreaks covering more or less extensive areas until 1960 when an opportunity was provided of spraying a small incipient infestation in the Lower St. Lawrence region of the Province of Quebec. It was hoped that early treatment might suppress the infestation and prevent its spread. Although the operation was successful in greatly reducing insect numbers in the area treated, it failed to arrest the infestation. Wind dispersal of first- and second-instar larvae prior to spray application resulted in the spread of the infestation beyond the area delimited for treatment. Also, the warm and dry weather in the spring of 1960, and the abundance of staminate flowers on the balsam fir and spruce trees greatly favoured larval survival. The aerial application of insecticides as a method of suppressing incipient spruce budworm outbreaks is discussed in the light of these results.


1958 ◽  
Vol 90 (6) ◽  
pp. 354-361 ◽  
Author(s):  
J. R. Blais

In 1956, the spruce budworm infestation which had been in progress in the Lower St. Lawrence and Gaspe Peninsula for about eight years, covered the whole territory from the Rimouski River to the eastern tip of the Peninsula (Fig. 1). In many localities throughout the region repeated defoliation had been severe enough to cause some trees to die (3) . Had it not been for the extensive aerial spraying operations practised in this region since 1954, tree mortality would undoubtedly have been even more widespread.


2021 ◽  
Author(s):  
Alvaro Fuentealba ◽  
Alain Dupont ◽  
Roberto Quezada-Garcia ◽  
Éric Bauce

Abstract Spruce budworm (Choristoneura fumiferana) is the most important pest of conifer forests in Eastern North America. The main approach to protect Quebec forests against this defoliator is aerial spraying of insecticides. Despite the crucial role of aerial spraying of insecticides in the global forest protection strategy, little is known about its real impact on tree mortality reduction or the stand characteristics that may affect its long-term efficacy. We evaluate the efficacy of the protection program implemented between 1967 and 1992 in reducing tree mortality during the previous outbreak in Quebec and how its efficacy is affected by stand characteristics such as drainage quality and stand age. We established 422 plots in Eastern Quebec based on the following parameters: insecticide application (0-13 years), stand composition, drainage quality, and stand age at the beginning of the previous outbreak. Our results show that unprotected plots exhibited in average between 18 and 32.6% higher mortality than protected plots. Insecticide efficacy was affected by drainage quality. For example, protected plots established on sites with bad drainage quality exhibited 49% less balsam fir mortality than unprotected plots. Furthermore, immature and mature protected stands exhibited a similar reduction in balsam fir mortality (32.2 and 32.1% less mortality respectively) compare to unprotected stands. Our results may be useful for decision-makers not only to decide where and when apply insecticides during a spruce budworm outbreak but also, they may help to determine the pertinence of continuous protection during longer than usual outbreaks depending on protection goal.


1973 ◽  
Vol 105 (12) ◽  
pp. 1535-1544 ◽  
Author(s):  
W. A. Smirnoff ◽  
J. J. Fettes ◽  
R. Desaulniers

AbstractA 10,000 acre stand of mature balsam fir, in Temiscouata County, Quebec, which had a spruce budworm population of about 21 larvae/18 in. branch-tip was sprayed with a Bacillus thuringiensis + chitinase formulation. Aerial spraying was carried out by three TBM aircraft between 4 and 7 June 1972, when insect development was at the peak of the third instar. Where the quantity of B. thuringiensis colonies per square centimeter was higher than 77 and spray deposit higher than 0.4 gal/acre (U.S.), larval mortality was between 84% and 93% compared with between 39% and 53% in the check plot. Foliage protection was 47%. The results indicate the possibilities of using B. thuringiensis + chitinase to control spruce budworm infestations.


1960 ◽  
Vol 92 (5) ◽  
pp. 384-396 ◽  
Author(s):  
J. R. Blais

A spruce budworm outbreak started in Quebec and adjoining parts of New Brunswick in 1949 and spread each year until by 1955 most balsam fir stands within an area of 32,000 square miles were attacked. Approximately 45 per cent of this area was in the Lower St. Lawrence and Gaspe regions of Quebec. In Quebec, important population reductions took place in various sectors of the outbreak area as a result of unfavourable weather conditions in 1956 and 1957 (Blais, 1958a, 1958b), and the final collapse occurred in 1958 when populations returned to the endemic level throughout the area (Blais and Martineau, 1958). In New Brunswick, a relatively small outbreak area remained at the end of the summer in 1958 (Webb et al., 1959). The large-scale aerial applications of DDT begun in New Brunswick in 1952, and in Quebec in 1954, were continued until 1958. Biological studies in connection with the spraying were carried out in both provinces. In Quebec these studies consisted of assessing spruce budworm population fluctuations in both sprayed and unsprayed areas and in determining, where possible, the causes for these fluctuations. All factors associated with changes in population could not be adequately measured over such a large territory, but a real attempt was made to obtain information on parasitism. The present paper deals with this aspect of the studies.


1948 ◽  
Vol 80 (1-12) ◽  
pp. 138-155 ◽  
Author(s):  
A. Wilkes ◽  
H. C. Coppel ◽  
W. G. Mathers

The spruce budworm, Choristoneura (Archips) fumiferana (Clem.) (Tortricidae) has long been considered one of the most injurious forest insect pests in Canada. A general account of past outbreaks and an outline of its biology and bahits are given by Swaine and Craighead (1924). At the time these studies were made investigations were also undertaken by J.D. Tothill and A.B. Baird on the parasites and other natural control factors of the spruce budworm, but although a good deal of work was done, brief reference to which is made by Hewitt (1911, 1912, 1913), very little has been published.


1964 ◽  
Vol 42 (6) ◽  
pp. 1017-1024 ◽  
Author(s):  
J. R. Blais ◽  
G. H. Parks

Control of a localized spruce budworm outbreak in southeastern Quebec was achieved through the combined effects of chemical treatment with DDT and natural control factors. Amongst the latter, predation by evening grosbeaks was suspected to have been of considerable importance. It appears that the birds were attracted to the outbreak area in unusually large numbers during their spring migration. The yearly influx of the grosbeaks in the area occurred when the budworm was in the late larval and the pupal stages, an especially critical period with respect to generation survival of this insect. In 1963, the year following collapse of the outbreak, very few grosbeaks were seen in the area. There was no direct evidence that the birds suffered ill effects from the spraying operation.


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