HOST ASSOCIATIONS IN SYMPATRIC POPULATIONS OF CHORISTONEURA OCCIDENTALIS FREEMAN AND C. RETINIANA (WALSINGHAM) (LEPIDOPTERA: TORTRICIDAE) IN SOUTH-CENTRAL OREGON AT HIGH POPULATION DENSITIES

1991 ◽  
Vol 123 (3) ◽  
pp. 713-715 ◽  
Author(s):  
Willis C. Schaupp
Keyword(s):  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Choristoneura Occidentalis ◽  
Western North America ◽  
Western Spruce Budworm ◽  
Population Densities ◽  
Sympatric Populations ◽  
Mixed Stands ◽  
South Central ◽  
White Fir

Sympatric, synchronous populations of conifer-feeding Choristoneura (Lepidoptera: Tortricidae) occur in western North America (Powell 1980). Choristoneura occidentalis Freeman, the western spruce budworm, co-exists with C. retiniana, the Modoc budworm, in mixed stands of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, and true firs, Abies spp. Choristoneura occidentalis has brown larvae and a broad geographic distribution associated with one of its principle hosts, Douglas-fir (Stehr 1967). Larvae of C. retiniana are green and feed on true firs, particularly white fir, Abies concolor (Gord. & Glend.) Lindl. (Stehr 1967; Carolin et al. 1987).

IMPLANTATION AND INJECTION OF SYSTEMICS TO SUPPRESS SEED AND CONE INSECTS IN DOUGLAS FIR IN MONTANA,

1985 ◽  
Vol 117 (8) ◽  
pp. 961-969 ◽  
Author(s):  
R.C. Reardon ◽  
L.J. Barrett ◽  
T.W. Koerber ◽  
L.E. Stipe ◽  
J.E. Dewey
Keyword(s):  
Pseudotsuga Menziesii ◽  
Seed Yield ◽  
Spruce Budworm ◽  
Douglas Fir ◽  
Choristoneura Occidentalis ◽  
Western Spruce Budworm ◽  
Systemic Insecticides ◽  
Filled Seeds

AbstractThe systemic insecticides oxydemeton-methyl and acephate were injected at 10- and 15-cm spacings, and acephate and dimethoate were implanted at 10-cm spacing in Douglas fir, Pseudotsuga menziesii var. glauca (Beissn.) Franco, to improve seed yield. Nutrients were also injected at 15-cm spacing. All treatments except nutrients and dimethoate increased the yield of filled seeds when compared with the checks. The western spruce budworm, Choristoneura occidentalis Freeman, and spruce coneworm, Dioryctria reniculelloides Mutuura and Munroe, caused most of the damage to cones.

Timing of Trunk-Implanted Acephate for Protection of Douglas-Fir from Defoliation by the Western Spruce Budworm

1988 ◽  
Vol 3 (4) ◽  
pp. 126-128 ◽  
Author(s):  
Thomas W. Koerber ◽  
Roger E. Sandquist
Keyword(s):  
Pseudotsuga Menziesii ◽  
Spruce Budworm ◽  
Weather Conditions ◽  
Douglas Fir ◽  
Choristoneura Occidentalis ◽  
Western Spruce Budworm ◽  
Defoliation Treatment ◽  
Favorable Weather

Abstract The effectiveness of implanting acephate in boles of superior Douglas-fir (Pseudotsuga menziesii var. glauca) to protect them from defoliation by western spruce budworm (Choristoneura occidentalis) and spruce cone-worm (Dioryctria reniculelloides) was investigated. April treatment afforded greater foliage protection than May treatment. November treatment was as effective as April in protecting trees from defoliation. Treatment in fall would be more efficient than in spring because of better road access and more favorable weather conditions. West. J. Appl. For. 3(4):126-128, October 1988.

scholarly journals Characterization of western spruce budworm outbreak regions in the British Columbia Interior

2018 ◽  
Vol 48 (7) ◽  
pp. 783-802 ◽  
Author(s):  
Lorraine E. Maclauchlan ◽  
Lori D. Daniels ◽  
Janice C. Hodge ◽  
Julie E. Brooks
Keyword(s):  
British Columbia ◽  
Spruce Budworm ◽  
Growth Suppression ◽  
Douglas Fir ◽  
Western North America ◽  
Western Spruce Budworm ◽  
The North ◽  
South Central ◽  
Ecosystem Classification

The western spruce budworm (WSB; Choristoneura freemani Razowski) shapes Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests throughout western North America with periodic, severe landscape-level defoliation events. The largest and most continuous recorded defoliation occurred in the 2000s, largely centered in the Williams Lake and 100 Mile House WSB outbreak regions, peaking in 2007 at 847 000 ha defoliated in British Columbia (B.C.). Unique WSB outbreak regions in south-central B.C. are described using biogeoclimatic ecosystem classification, geography, 106 years of documented defoliation, and 46 stand-level Douglas-fir host tree-ring chronologies. Since the 1980s, recorded defoliation in B.C. has shifted from coastal ecosystems and become a dominant disturbance in drier, colder, interior Douglas-fir ecosystems. Defoliation records demarcate four outbreaks from 1950–2012 and up to three growth suppression events from 1937–2012. Outbreak duration was shorter in the north and far south of B.C., with recovery periods (no trees showing growth suppression) shorter over all WSB outbreak regions in the 2000s, suggesting that trees may be increasingly susceptible to each successive defoliation event. Knowing the regional outbreak periodicity may facilitate early detection of incipient WSB populations, which is critical for management as many of our low-elevation Douglas-fir forests become more stressed with changing and unpredictable climate regimes.

Western Spruce Budworm Damage to Sprayed and Unsprayed Young Douglas-Fir

1988 ◽  
Vol 3 (2) ◽  
pp. 44-46 ◽  
Author(s):  
Rene I. Alfaro ◽  
Emil Wegwitz
Keyword(s):  
British Columbia ◽  
Regression Model ◽  
Pseudotsuga Menziesii ◽  
Tree Mortality ◽  
Spruce Budworm ◽  
Douglas Fir ◽  
Choristoneura Occidentalis ◽  
Western Spruce Budworm

Abstract Defoliation, mortality, and top-kill were measured in 40-year-old, open-grown Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) under attack by the western spruce budworm (Choristoneura occidentalis [Freeman]) in the interior of British Columbia, in control trees and trees treated with ground sprays of the insecticide Sevin. In untreated trees that sustained repeated defoliation of 50 to 90% of the total crown foliage, tree mortality began after four years and had reached 29% after eight years. Thirty-four percent of the survivors in this group suffered top-kill, which averaged 1.0 m at the end of eight years. No mortality and only negligible top-kill occurred in trees, sprayed or not, which sustained less than 50% defoliation. A regression model of the probability of tree mortality based on the defoliation is presented. West. J. Appl. For. 3(2):44-46, April 1988.

THIODICARB AND SULPROPHOS APPLIED TO WESTERN SPRUCE BUDWORM, CHORISTONEURA OCCIDENTALIS (LEPIDOPTERA: TORTRICIDAE), WITH AN AERIAL SPRAY SIMULATOR

1983 ◽  
Vol 115 (4) ◽  
pp. 357-359
Author(s):  
Charles E. Richmond
Keyword(s):  
Pseudotsuga Menziesii ◽  
Large Scale ◽  
Spruce Budworm ◽  
Douglas Fir ◽  
Choristoneura Occidentalis ◽  
Mortality Level ◽  
Western Spruce Budworm

AbstractThiodicarb and sulprophos were applied to western spruce budworm, Choristoneura occidentalis Freeman, which were infesting small Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco. An aerial spray simulator was used for this application at three dosages. At 105 and 160 g a.i./ha, thiodicarb reduced the number of larvae/100 buds by at least 90%. Sulprophos failed to achieve the target mortality level of 90% or better, even at the highest dosage tested—at 380 g a.i./ha sulprophos reduced the number of larvae/100 buds by 74%. Thiodicarb appears to be the better candidate for future large-scale aerial tests.

PROTECTION OF DOUGLAS-FIR FOLIAGE FROM WESTERN SPRUCE BUDWORM (LEPIDOPTERA: TORTRICIDAE) DAMAGE BY EARLY APPLICATIONS OF ACEPHATE (ORTHENE 75S)

1978 ◽  
Vol 110 (11) ◽  
pp. 1127-1132 ◽  
Author(s):  
Charles E. Richmond ◽  
Robert D. Averill ◽  
Carl E. Crisp
Keyword(s):  
Liquid Chromatography ◽  
Pseudotsuga Menziesii ◽  
Active Metabolite ◽  
Spruce Budworm ◽  
Significant Degree ◽  
Douglas Fir ◽  
Gas Liquid Chromatography ◽  
Choristoneura Occidentalis ◽  
Western Spruce Budworm

AbstractAcephate (Orthene 75S) was applied to Douglas-fir (Pseudotsuga menziesii Mirbl. [Franco]) in spring 1976 to determine its efficacy for protecting current year’s foliage from western spruce budworm (Choristoneura occidentalis Freeman). Results showed budworm mortality for both treatments exceeded the checks by at least 91% at all sample periods. A significant degree of foliage protection was also achieved as measured by mean twig length and mean number of missing needles per twig. Samples of new growth were analyzed for residues of acephate and methamidophos (an active metabolite of acephate) by gas-liquid chromatography. Results showed that high levels of insecticide persisted for about 10 days, then dropped over a 5-day period to lower levels for the rest of the study, about 35 days.

RELATIONSHIPS BETWEEN ATTACK RATES AND SURVIVAL OF WESTERN SPRUCE BUDWORM, CHORISTONEURA OCCIDENTALIS FREEMAN (LEPIDOPTERA: TORTRICIDAE), AND BUD DEVELOPMENT OF DOUGLAS-FIR, PSEUDOTSUGA MENZIESII (MIRB.) FRANCO

1992 ◽  
Vol 124 (2) ◽  
pp. 347-358 ◽  
Author(s):  
Roy F. Shepherd
Keyword(s):  
Close Association ◽  
Spruce Budworm ◽  
Larval Survival ◽  
Douglas Fir ◽  
Choristoneura Occidentalis ◽  
Western Spruce Budworm ◽  
Bud Development ◽  
Feeding Sites ◽  
Vegetative Buds ◽  
Wide Range

AbstractIndividual larvae of western spruce budworm (Choristoneura occidentalis Freeman) were observed from overwintering emergence to pupation at six locations spread over a wide range of altitudes and thus climate. A weekly census of 100 lower-crown buds per plot indicated large differences in rates of bud development and larval survival among locations.Emerging second-instar larvae attempted to mine swelling buds of Douglas-fir. If the buds were hard and tight, larvae mined 1-year-old needles until penetrable buds were available. Larvae dispersed over the crowns with only one larva becoming established in each bud; thus, many early-emerging and surplus larvae could not find suitable feeding sites and disappeared. Within the protective bud, survival was high. After buds flushed and larvae became exposed, densities dropped, probably due to increased predation and decreased food quality. Correlations indicated a close association between larval survival for the exposed period between bud flush and pupation, and overall larval survival.Douglas-fir trees responded to initial bud removal, but not to needle removal, by inducing latent buds in the axils of needles to grow into active vegetative buds ready to develop and flush the next spring. The number of these new vegetative buds formed was greatest when the initial buds were removed early in the season before flush, and decreased thereafter. Trees with vigorous crowns had the greatest response to defoliation by inducing the largest number of latent buds into becoming active vegetative buds; these were found mainly on the 2- and 3-year-old internodes.

INFLUENCE OF FOLIAR NITROGEN LEVELS ON SURVIVAL, DEVELOPMENT, AND REPRODUCTION OF WESTERN SPRUCE BUDWORM, CHORISTONEURA OCCIDENTALS (LEPIDOPTERA: TORTRICIDAE)

1985 ◽  
Vol 117 (1) ◽  
pp. 23-32 ◽  
Author(s):  
J. Wayne Brewer ◽  
John L. Capinera ◽  
Robert E. Deshon ◽  
Mary L. Walmsley
Keyword(s):  
Larval Mortality ◽  
Spruce Budworm ◽  
Dry Weight ◽  
Douglas Fir ◽  
Nitrogen Level ◽  
Pupal Weight ◽  
Western Spruce Budworm ◽  
Foliar Nitrogen ◽  
Nitrogen Levels ◽  
White Fir

AbstractThe influence of nitrogen levels in foliage of white-fir, Abies concolor, and Douglas-fir, Pseudotsuga menziesii, seedlings on various biological characteristics of the western spruce budworm, Choristoneura occidentalis Freeman, was studied. Seedlings were grown under greenhouse conditions and provided with nutrient solutions to maintain five foliar nitrogen levels ranging from 1.29 to 4.42% dry weight for white fir and 1.43 to 3.94% for Douglas fir. Larvae confined to treated seedlings were monitored through the next generation. Larval mortality was higher, and development time longer, at both upper and lower extremes of foliar nitrogen than at mid-level. Mean pupal weight was significantly greater for larvae reared on white fir with the mid-range foliar-nitrogen level. Mean number, and weight, of eggs laid were highest when larvae fed on foliage from the mid-range nitrogen level. Total number of larvae produced was lowest at the high and low extremes of foliar nitrogen levels.

scholarly journals Production potential of Douglas fir at mesotrophic sites of Křtiny Training Forest Enterprise

2008 ◽  
Vol 54 (No. 7) ◽  
pp. 321-332 ◽  
Author(s):  
P. Kantor
Keyword(s):  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Production Potential ◽  
European Larch ◽  
Mixed Stands ◽  
Production Parameters ◽  
Breast Height ◽  
The Mean ◽  
The One ◽  
Mature Stands

: The study evaluates production parameters (height, diameter at breast height, volume) of Douglas fir (<I>Pseudotsuga menziesii</I> [Mirb.] Franco) at mesotrophic sites of the Křtiny Training Forest Enterprise in mature stands. In total, 29 mixed stands were assessed with the registered proportion of Douglas fir at an age of 85 to 136 years. Comparing the 10 largest Douglas firs with the 10 largest spruces or larches higher, and as a rule markedly higher, production potential of introduced Douglas fir was found in all assessed stands. There were also groups of trees where the volume of Douglas fir was twice to 3 times higher than the volume of spruce or larch (see Tabs. 5 to 10). For example, in stand 177B11, the mean volume of 9.12 m<sup>3</sup> was recorded in the 10 largest Douglas fir trees but the volume of spruce reached only 3.17 m<sup>3</sup> and the volume of larch was 3.70 m<sup>3</sup>. Differences in mensurational parameters of Douglas fir found on the one hand and of Norway spruce (<I>Picea abies</I> [L.] Karst.) or European larch (<I>Larix decidua</I> Mill.) on the other hand compared by ANOVA tests were statistically highly significant. Annual ring analyses have shown that at present the volume increment of particular Douglas fir trees ranges from 0.12 to 0.16 m<sup>3</sup> per year in mature stands (i.e. about 1.5 m<sup>3</sup> every 10 years).

EARLY GROUND APPLICATION OF ACEPHATE FOR CONTROL OF THE WESTERN SPRUCE BUDWORM (LEPIDOPTERA: TORTRICIDAE) ON DOUGLAS-FIR

1977 ◽  
Vol 109 (9) ◽  
pp. 1153-1158 ◽  
Author(s):  
J. Wayne Brewer ◽  
J. O’Neal
Keyword(s):  
Aqueous Solution ◽  
Larval Mortality ◽  
Spruce Budworm ◽  
Douglas Fir ◽  
Choristoneura Occidentalis ◽  
Regression Analyses ◽  
Western Spruce Budworm ◽  
Systemic Action ◽  
Equipment Application

AbstractThe insecticide acephate (0.5-dimethyl acetyl phosphoramidothioate) was applied at 0.5, 1.0, and 1.5 lb A.I./gal (.058, 0.118, 0.179 kg/l.) in aqueous solution to individual Douglas-fir trees infested with western spruce budworm, Choristoneura occidentalis Freeman, larvae in central Washington using hand held ground application equipment. Application was made when larvae were in the needle mining – bud mining stage at rates ranging from 2.58 to 5.10 gal/acre (3.97 to 7.84 l./ha). For all three concentrations, mortality of larvae inside needles was 94–98% after 1 day compared with a check mortality of 18% and larval mortality inside buds was 99% after 1 day compared with 23% for the check. Regression analyses indicated that defoliation was positively correlated with the number of needles mined the current year and per cent punctured buds, and negatively correlated with larval mortality inside both needles and buds. The data suggest that when applied at the rates used, acephate has some type of systemic action and can provide foliage protection during the year of application.

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