Douglas-fir Tussock Moth Damage in British Columbia

1987 ◽  
Vol 63 (5) ◽  
pp. 351-355 ◽  
Author(s):  
R. I. Alfaro ◽  
E. Wegwitz ◽  
R. G. Brown ◽  
S. P. Taylor
Keyword(s):  
British Columbia ◽  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Cumulative Mortality ◽  
Tussock Moth ◽  
Orgyia Pseudotsugata ◽  
Dead Trees ◽  
The Dead

The Douglas-fir tussock moth (Orgyia pseudotsugata McDunnough) defoliated Douglas-fir (Pseudotsuga menziesii var glauca [Beissn.] Franco), in British Columbia from 1981 to 1983. Forty-five defoliated and 16 non-defoliated (check) plots were monitored for defoliation and damage from 1982 to 1985. By 1985, cumulative mortality and top-kill in the defoliated plots averaged 51% (49% by volume) and 11%, respectively. Check plots sustained no mortality and less than 1% top-kill due to causes other than tussock moth defoliation. Mortality occurred very early in the outbreak, with 56% of the dead trees already dead by 1982, generally after 1 year, but at most after 2 years of defoliation. Mortality and top-kill were related to the number of seasons of defoliation and, particularly, to defoliation intensity. It was concluded that Douglas-fir tussock moth is an important depletion factor of Douglas-fir in British Columbia.

EVIDENCE OF SYNCHRONIZED CYCLES IN OUTBREAK PATTERNS OF DOUGLAS-FIR TUSSOCK MOTH, ORGYIA PSEUDOTSUGATA (McDUNNOUGH) (LEPIDOPTERA: LYMANTRIIDAE)

1988 ◽  
Vol 120 (S146) ◽  
pp. 107-121 ◽  
Author(s):  
Roy F. Shepherd ◽  
Dayle D. Bennett ◽  
John W. Dale ◽  
Scott Tunnock ◽  
Robert E. Dolph ◽  
...  
Keyword(s):  
British Columbia ◽  
North America ◽  
Single Particle ◽  
Douglas Fir ◽  
Western North America ◽  
Tussock Moth ◽  
Orgyia Pseudotsugata ◽  
Northern Idaho

AbstractOutbreak patterns of Douglas-fir tussock moth, Orgyia pseudotsugata (McDunnough), over western North America historically appear to be synchronous, particularly in British Columbia, Washington, Oregon, and northern Idaho. Populations of the insect increase to outbreak and collapse in a variable cycle, averaging 9 years between peaks. A review of all outbreaks suggests repeated, widespread, nucleopolyhedrosis viral epizootics are responsible for the collapse of the population and, hence, the cycle. The virus appears to survive in the soil between outbreaks and to be carried incidentally to foliage where it is occasionally consumed by larvae. Ingestion of a single particle is probably sufficient to cause infection. Populations of the moth increase until density reaches the point where larvae to larvae infection is established. The viral inoculum builds rapidly following that point and spreads widely so that distant populations at all densities become infected, and collapse in the same year. The epizootic continues for another year. Then foliage contamination disappears, and populations reach their lowest densities before starting the cycle again.

Cylindrocarpon and Fusarium root colonization of Douglas-fir seedlings from British Columbia reforestation sites

1998 ◽  
Vol 28 (8) ◽  
pp. 1198-1206 ◽  
Author(s):  
Paige E Axelrood ◽  
William K Chapman ◽  
Keith A Seifert ◽  
David B Trotter ◽  
Gwen Shrimpton
Keyword(s):  
British Columbia ◽  
Pseudotsuga Menziesii ◽  
Root Colonization ◽  
Linear Trend ◽  
Poor Performance ◽  
Douglas Fir ◽  
Root Infection ◽  
Significant Linear Trend ◽  
Conifer Seedlings ◽  
Cylindrocarpon Destructans

Poor performance of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantations established in 1987 has occurred in southwestern British Columbia. Affected sites were planted with 1-year-old container stock that exhibited some root dieback in the nursery. A study was initiated in 1991 to assess Cylindrocarpon and Fusarium root infection in planted and naturally regenerating (natural) Douglas-fir seedlings from seven affected plantations. Percentages of seedlings harboring Cylindrocarpon spp.and percent root colonization were significantly greater for planted seedlings compared with natural seedlings. A significant linear trend in Cylindrocarpon root colonization was observed for planted seedlings with colonization levels being highest for roots closest to the remnants of the root plug and decreasing at distances greater than 10cm from that region. This trend in Cylindrocarpon colonization was not observed for natural seedlings. Cylindrocarpon destructans (Zins.) Scholten var. destructans and C.cylindroides Wollenw. var. cylindroides were the only species isolated from planted and natural conifer seedlings. For most sites, percentage of seedlings harboring Fusarium spp.and percent Fusarium root colonization were less than for Cylindrocarpon. Recovery of Fusarium spp.from seedlings and root colonization levels were not significantly different for planted and natural seedlings from all sites.

Contarinia pseudotsugae. [Distribution map].

2020 ◽  
Author(s):  
Keyword(s):  
British Columbia ◽  
North America ◽  
Geographical Distribution ◽  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Distribution Map ◽  
New Distribution ◽  
Distribution In Europe

Abstract A new distribution map is provided for Contarinia pseudotsugae Condrashoff (Diptera: Cecidomyiidae). Hosts: Douglas fir (Pseudotsuga menziesii). Information is given on the geographical distribution in Europe (Belgium, France, Germany and Netherlands) and North America (Canada, British Columbia, USA, California, Idaho, Michigan, Montana, Oregon, Pennsylvania and Washington).

Rhabdocline pseudotsugae. [Distribution map].

1976 ◽  
Author(s):  
Keyword(s):  
British Columbia ◽  
North America ◽  
Geographical Distribution ◽  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Distribution Map ◽  
Irish Republic ◽  
New Distribution ◽  
Distribution In Europe

Abstract A new distribution map is provided for Rhabdocline pseudotsugae Syd. Hosts: Douglas fir (Pseudotsuga menziesii). Information is given on the geographical distribution in EUROPE, Belgium, Britain, Czechoslovakia, Denmark, France, Germany, Irish Republic, Netherlands, Norway, Poland, Romania, Sweden, Switzerland, Yugoslavia, NORTH AMERICA, Canada (Alberta, British Columbia), USA.

Dendroctonus pseudotsugae. [Distribution map].

2004 ◽  
Author(s):  
Keyword(s):  
British Columbia ◽  
New Mexico ◽  
North America ◽  
Geographical Distribution ◽  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Distribution Map ◽  
Dendroctonus Pseudotsugae ◽  
New Distribution

Abstract A new distribution map is provided for Dendroctonus pseudotsugae Hopkins Coleoptera: Scolytidae Hosts: Mainly Douglas fir (Pseudotsuga menziesii), also other Pseudotsuga spp. Information is given on the geographical distribution in NORTH AMERICA, Canada, Alberta, British Columbia, Mexico, USA, Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Texas, Utah, Washington, Wyoming.

scholarly journals Adjacency to a harvest trail increases drought resistance of interior Douglas-fir (Pseudotsuga menziesii var. glauca) in partially harvested stands in central British Columbia

2018 ◽  
Vol 48 (7) ◽  
pp. 809-820 ◽  
Author(s):  
Neil P. Thompson ◽  
Kathy J. Lewis ◽  
Lisa M. Poirier
Keyword(s):  
British Columbia ◽  
Drought Tolerance ◽  
Pseudotsuga Menziesii ◽  
Growth Rates ◽  
Habitat Management ◽  
Odocoileus Hemionus ◽  
Douglas Fir ◽  
Ring Analysis ◽  
The Relationship

Drought tolerance of trees may be affected by competition, but most studies quantifying the relationship do not consider the effect of stem clustering. Trees are often clustered in interior Douglas-fir (Pseudotsuga menziesii var. glauca (Mayr) Franco) forests near the grassland interface in central British Columbia due to past harvesting practices or habitat management for mule deer (Odocoileus hemionus hemionus (Rafinesque, 1817)). Climate change projections indicate continued increases in temperature, an outcome that would stress trees growing in dry environments. Trees placed in different states of competition by mechanical harvesting in the 1970s were sampled to provide a 40-year comparison of three levels of competition during 1–2 year droughts. Tree-ring analysis was used to assess the reduction in growth during drought years and resumption of growth in subsequent years. A clear separation of growth rates was evident between open-growing trees, trees on the edge of harvesting trails, and trees within the unharvested interior. Edge trees had intermediate growth rates but no differences were found in the long-term climate–growth relationship compared with open-growing trees. Both Edge and Open classes showed less relative growth reduction during droughts than Interior trees growing between harvest trails. Precipitation throughfall rates and competition for resources are likely driving short-term drought tolerance in combination with other factors.

scholarly journals Impact of Biochar on Douglas-Fir Tussock Moth (Orgyia pseudotsugata Lepidoptera: Erebidae) Larvae Reared on Synthetic Die

Insects ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1065
Author(s):  
Stacey Rice-Marshall ◽  
Stephen P. Cook ◽  
John Randall
Keyword(s):  
Weight Gain ◽  
Larval Mortality ◽  
Douglas Fir ◽  
High Concentration ◽  
Larval Weight ◽  
Synthetic Diet ◽  
Tussock Moth ◽  
Orgyia Pseudotsugata ◽  
Compensatory Feeding ◽  
Significant Difference

The use of biochar as a soil amendment in forest ecosystems can be beneficial in the restoration of degraded soils. Forest insects such as the Douglas-fir tussock moth, Orgyia pseudotsugata (McDonnough) (Lepidoptera: Erebidae), may be exposed to biochar when the material is applied. Two experiments were conducted using biochar either (1) applied to the surface of the diet at three rates (0, 5, and 10 mg) or (2) incorporated into synthetic diet at four rates (0, 10, 20, and 40% volume/volume). The objective of both experiments was to determine if biochar on the surface or incorporated into a synthetic diet affected development and survival of O. pseudotsugata larvae. In both experiments, there was a significant decrease in estimated time to larval mortality in all biochar treatments compared to untreated controls. In the surface-applied biochar experiment, there was a significant difference in larval weight gain at day 12 between the control and 10 mg biochar treatments. In the experiment with biochar incorporated into the diet, mean larval weight at day 12 was highest in the low (10%) biochar treatment compared to all other treatments, although weight gain was only significantly different between the low- and high-concentration (40%) biochar treatments. Our results suggest that larvae, feeding on a low amount of biochar in the synthetic diet, may respond by engaging in compensatory feeding behavior. Fewer surviving larvae in the biochar treatment groups may contribute to the lack of significance found in the comparison of weight gain at day 24 in each experiment.

PEST MANAGEMENT OF DOUGLAS-FIR TUSSOCK MOTH (LEPIDOPTERA: LYMANTRIIDAE): A SEQUENTIAL SAMPLING METHOD TO DETERMINE EGG MASS DENSITY

1984 ◽  
Vol 116 (7) ◽  
pp. 1041-1049 ◽  
Author(s):  
R. F. Shepherd ◽  
I. S. Otvos ◽  
R. J. Chorney
Keyword(s):  
Sampling Method ◽  
Mass Density ◽  
Sequential Sampling ◽  
Douglas Fir ◽  
Egg Mass ◽  
Tussock Moth ◽  
Incipient Stage ◽  
Orgyia Pseudotsugata ◽  
Detection Tool ◽  
Variability Data

AbstractA sequential egg-mass sample system for Douglas-fir tussock moth, Orgyia pseudotsugata McDunnough (Lepidoptera: Lymantriidae), was designed, based on visual scanning of the lower branches of Douglas-fir trees, Pseudotsuga menziesii (Mirb.) Franco. A branch was removed from each quadrant from the upper, middle and lower crown level, and from the lowest whorl of a total of 59 non-defoliated trees in 10 areas. No consistent trend in egg-mass density per branch could be found between crown levels and no level proved superior as a representative of the tree. Therefore, the lower whorl of branches was selected for survey purposes because of sampling efficiency. Sample stop lines were determined from egg-mass density and variability data collected on 55 sites and subsequent defoliation estimates were related to these densities. The system is designed as an early detection tool to be used only in non-defoliated stands at the incipient stage of an impending outbreak.

TOXICITY OF INSECTICIDES TO DOUGLAS-FIR TUSSOCK MOTH, ORGYIA PSEUDOTSUGATA (LEPIDOPTERA: LYMANTRIIDAE): I. CONTACT AND FEEDING TOXICITY

1979 ◽  
Vol 111 (10) ◽  
pp. 1145-1159 ◽  
Author(s):  
Jacqueline L. Robertson ◽  
Lucille M. Boelter
Keyword(s):  
Rhodamine B ◽  
Douglas Fir ◽  
Relative Toxicity ◽  
Spray Chamber ◽  
Population Response ◽  
Larval Stages ◽  
Tussock Moth ◽  
Orgyia Pseudotsugata ◽  
Rhodamine B Dye ◽  
Spray Volume

AbstractThe toxicities of 14 insecticides to selected larval stages of the Douglas-fir tussock moth were determined with a laboratory spray chamber. The toxicities of 10 were also determined in feeding bioassays. Younger instars were, in general, more susceptible to the toxicants. Significant differences in population response from 1973 to 1977 precluded a rigid interpretation of relative toxicity values in relation to the standard for comparison, DDT. Spray volume, formulation, and the presence of rhodamine B dye significantly affected toxicities of two of the materials, carbaryl and trichlorfon. The degree of exposure of larvae to bioethanomethrin and carbaryl significantly affected mortality.

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