Influence du drainage et de la texture du dépôt sur la vulnérabilité du Sapin baumier et de l'Épinette blanche aux attaques de la Tordeuse des bourgeons de l'épinette

1990 ◽  
Vol 20 (6) ◽  
pp. 750-756 ◽  
Author(s):  
Louis Archambault ◽  
Robert R. Gagnon ◽  
Georges Pelletier ◽  
Michel Chabot ◽  
Louis Bélanger
Keyword(s):  
Soil Moisture ◽  
Pest Management ◽  
Soil Texture ◽  
Spruce Budworm ◽  
White Spruce ◽  
Balsam Fir ◽  
Moisture Regime ◽  
Soil Moisture Regime ◽  
Ecosystem Classification ◽  
Spruce Mortality

Balsam fir (Abiesbalsamea (L.) Mill.) and white spruce (Piceaglauca (Moench) Voss) mortality was measured in five areas of the province of Quebec severely affected by spruce budworm (Choristoneurafumiferana (Clem.)) defoliation. Mortality was compared for different combinations of soil texture and drainage. For balsam fir, two vulnerability classes, based on combinations of soil texture and drainage, were defined. In the first class, mortality reached 74% of the preoutbreak volume, as compared with 86% in the second class. For white spruce, three vulnerability classes were defined based on soil texture and drainage combinations. In the low, moderate, and high vulnerability classes, white spruce mortality reached 10, 26, and 52%, respectively. Soil moisture regime is an important factor in determining vulnerability. From these results, we propose an ecosystem classification based on vulnerability to spruce budworm. Particular reference is made to what significance the findings may have for forest integrated pest management.

Mortality of balsam fir and white spruce following a spruce budworm outbreak in the Ottawa River watershed in Quebec

1981 ◽  
Vol 11 (3) ◽  
pp. 620-629 ◽  
Author(s):  
J. R. Blais
Keyword(s):  
Twentieth Century ◽  
Spruce Budworm ◽  
White Spruce ◽  
Balsam Fir ◽  
Forest Roads ◽  
River Watershed ◽  
Ottawa River ◽  
High Incidence ◽  
Spruce Mortality ◽  
Mature Stands

Spruce–fir stands in the Ottawa River watershed in Quebec were subjected to defoliation by spruce budworm, Choristoneurafumiferana (Clem.), between 1967 and 1975. Eighteen study plots were established in mixed and coniferous mature stands to determine impact of the infestation on balsam fir, Abiesbalsamea Mill., and white spruce, Piceaglauca (Moench) Voss, and the protracted mortality of these two species following the end of the infestation. The plots were established in 1975, the last year of defoliation, and revisted each year until 1979. Between 1975 and 1979, fir mortality increased from 44 to 91%, and spruce mortality from 17 to 52%. Thus, more than 50% of the trees of both species that died did so during the 4 years after cessation of defoliation. Mortality for both spruce and fir was as high for mixed (hardwoods and budworm hosts) as for coniferous (predominantly spruce and fir) stands. A survey along 710 km of forest roads conducted in the study area in 1980 indicated the degree of mortality observed in the plots was representative of that for the whole region, and that mortality in young stands (20–50 years) was almost as high as in mature fir stands. Since the beginning of the twentieth century, intervals between budworm outbreaks lasted about 30 years in the Ottawa River watershed. However, the high incidence of mortality of white spruce and of immature fir that occurred during the recent infestation was not observed during earlier infestations. Regeneration of fir is plentiful throughout the area, but it will take some time before these young trees attain maturity and become susceptible to budworm attack. The interval between this recent and the next budworm infestation should therefore be longer than preceding ones.

Comparison of black spruce (Picea mariana) radial growth reduction in different soil moisture regimes during a spruce budworm (Choristoneura fumiferana) outbreak

2012 ◽  
Vol 42 (7) ◽  
pp. 1410-1419 ◽  
Author(s):  
Melissa E. Lacey ◽  
Jeffery P. Dech
Keyword(s):  
Soil Moisture ◽  
Picea Mariana ◽  
Radial Growth ◽  
Black Spruce ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Moisture Regime ◽  
Growth Reduction ◽  
Soil Moisture Regime ◽  
Moisture Regimes

The objective of this study was to determine if the stand‐level soil moisture regime had a significant effect on the reduction in black spruce (Picea mariana (Mill.) B.S.P.) radial growth during the most recent spruce budworm (Choristoneura fumiferana Clem.) outbreak in the boreal forest region of northeastern Ontario. We collected a stratified random sample of co-dominant black spruce trees from three moisture regimes and compared the reduction of radial growth during a spruce budworm outbreak between dry, moist, and wet stands. We focused on the most recent outbreak from 1975–1987, which we dated by dendrochronological analysis of black spruce increment cores from the Romeo Malette Forest near Timmins, Ontario. Samples collected from dry and moist sites showed significantly greater maximum radial growth reduction than those from wet sites. Mean growth reduction over the entire outbreak was not significantly different among moisture regimes but followed the same trend. We found no evidence of spatial autocorrelation in the growth reduction response, suggesting that the moisture effect was not confounded by location.

Soil Moisture Regime Changes in Tephra-Mulched Soils

2002 ◽  
Vol 66 (1) ◽  
pp. 202 ◽  
Author(s):  
M. Tejedor ◽  
C. C. Jiménez ◽  
F. Díaz
Keyword(s):  
Soil Moisture ◽  
Moisture Regime ◽  
Regime Changes ◽  
Soil Moisture Regime

LONG TERM STUDY OF THE EFFECTIVENESS OF AERIAL APPLICATION OF BACILLUS THURINGIENSIS – ACEPHATE COMBINATIONS AGAINST THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

1977 ◽  
Vol 109 (9) ◽  
pp. 1239-1248 ◽  
Author(s):  
O. N. Morris
Keyword(s):  
Bacillus Thuringiensis ◽  
Choristoneura Fumiferana ◽  
Larval Mortality ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
White Spruce ◽  
Balsam Fir ◽  
Population Densities ◽  
Long Term Study

AbstractBacillus thuringiensis (Dipel® 36B) mixed with a sublethal concentration of acephate (Orthene®) (O, S-dimethyl acetylphosphoramidothioate), an organophosphorous insecticide, was applied at 2.35–14 l./ha to white spruce (Picea glauca) and balsam fir (Abies balsamea) trees infested with spruce budworm, Choristoneura fumiferana (Clem.). The treatment rate was 20 Billion International Units of B. thuringiensis (B.t.) activity with or without 42 g of active ingredient of acephate/ha.The ground deposit of the standard Dipel wettable powder formulation was 12% of emitted volume compared with 21–32% for the Dipel 36B flowable. The viability of B.t. spores was drastically reduced after 1 day of weathering but a high level of biological activity by the spore–crystal complex persisted for up to 20 days post-spray due probably to crystal activity.The addition of about 10% of the recommended operational rate of acephate to the B.t. suspension increased larval mortality by 34% when applied at 4.7 l./ha. Reductions in budworm populations were 97–99% in B.t. + acephate plots and 86–90% in B.t. alone plots.Plots with moderate budworm densities of up to 27 larvae/100 buds on white spruce and 36/100 on balsam fir were satisfactorily protected from excessive defoliation in the year of spray by B.t. with or without acephate. Plots with higher population densities were not satisfactorily protected based on the branch sample examination but aerial color photographs indicated good protection to the top third of the trees. Population declines were greater and defoliation and oviposition were lower in the treated plots than in the untreated checks 1 year later without further treatment. Two years later the larval population densities in all plots were low but the density was twice as high in the untreated check as in the treated plots, indicating long term suppression by the treatments. Defoliation was negligible in all plots.The treatments had no deleterious effect on spruce budworm parasitism. The data indicate that the integrated approach using Bacillus thuringiensis – chemical pesticide combinations is a viable alternative to the use of chemical pesticides alone in spruce budworm control. Large scale testing is now warranted.

The soil moisture regime under native grassland

Geoderma ◽  
1975 ◽  
Vol 14 (3) ◽  
pp. 207-221 ◽  
Author(s):  
E.De Jong ◽  
K.B. MacDonald
Keyword(s):  
Soil Moisture ◽  
Moisture Regime ◽  
Soil Moisture Regime ◽  
Native Grassland
Sign in / Sign up

Export Citation Format

Share Document