The objectives undertaken in this study were:
1) to develop means of identifying the immature stages of
the known insect predators and parasites of the Douglas-fir beetle; 2) to investigate the possible distribution,
spatially and/or temporal, of the known insect predators
and parasites in standing trees infested by the Douglas-fir...
The objectives of this study were: 1) to learn the life history and habits of Medetera aldrichii Wheeler and a Lonchaea sp. in association with the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, in western Oregon and Washington; 2) to determine if the larvae of M. aldrichii were predaceous on the Douglas-fir...
Three coleopterous predators associated with the Douglas-fir
beetle (Dendroctonus pseudotsugae Hopkins in a second growth
forest of Douglas-fir (Pseudotsugae menziesii (Mirb. ) Franco)
in western Oregon are Enoclerus sphegeus Fabriciup, E, lecontei
Wolcott, and Thanasirnus undatulus Say. A study was undertaken
with the following objectives: (1) to determine the diurnal...
Factors considered were phloem moisture, sour-phloem (which
may be furthered by the presence of ample phloem moisture), oleoresin of the host, and the presence of unmated female beetles in
suitable host material.
Levels of phloem moisture present in variously prepared logs
in the field ranged from about 100 to upwards...
The bionomics of Medetera aldrichii Wheeler (Diptera:
Dolichopodidae), a predator of the Douglas-fir beetle (Dendroctonus
pseudotsugae Hopkins (Coleoptera:Scolytidae)), was investigated
in western Oregon.
The predator pupated in host galleries proximal to bark beetle
ventilation holes. The tendency of prepupal larvae to form pupal
cells near illuminated areas in a photo-response...
Oxygen uptakes of Douglas-fir beetles collected during November
1969 through April 1970 were measured at different experimental temperatures.
The oxygen uptakes of adult beetles increased at each
experimental temperature as the seasons progressed from winter to
spring.
The larval and pupal Douglas-fir beetles, collected in February
1970, had lower oxygen...
The effect of competition on the brood survival of the Douglas fir
beetle Dendroctonus pseudotsugae Hopkins, in down or windthrown
Douglas-fir Pseudotsuga menziesii (Mirb.) Franco was studied in the
field and the laboratory. The investigation of the role of competition
in the population dynamics of the beetle had four objectives:...
The study was undertaken to determine the seasonal and diurnal
flight patterns of scolytid beetles inhabiting a second growth
forest of Douglas-fir (Pseudotsuga menziesii (Mirb.)Franco) in western
Oregon. Air temperatures, relative humidity, light intensity, and wind
velocities were recorded for evaluation of their influence on flight activity.
The insects were...
The flight behavior of Ips confusus (Lec.) was primarily
studied under field conditions, but augmented with
complementary laboratory studies whenever feasible. The
experiments were mostly conducted in areas of endemic population
levels, but also under epidemic and prairie conditions.
The techniques and devices used in marking, releasing,
attracting, and trapping...
Six species of Cleridae, including Enoclerus spegeus Fabricius,
E. lecontei Wolcott, E. schaefferi (Barr), E. eximius Mannerheim,
Thanasimus undatulus Say, and an undescribed species of Enoclerus,
were found on Douglas-fir in western Oregon. E. sphegeus was the
only clerid of the six species studied which was primarily associated
with the...
Behavioral responses exhibited by the Douglas-fir beetle,
Dendroctonus pseudotsugae Hopkins, to various attractant sources
were investigated under both laboratory and field conditions. Tests
were designed to observe olfactory responses. Results were correlated
and compared with collections from sampling nets and with
emergence patterns. Field data were collected during the flight...
An outbreak of Douglas-fir beetle, Dendroctonus pseudotsugae Hopk., began in 1969 in the North Fork Clearwater River drainage in northern Idaho. This infestation probably resulted from trees felled during clearing for the Dworshak Reservoir, from ice and snow breakage which occurred during the winter of 1968-69 in stands adjacent to...
Published July 1966. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published October 1965. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published October 1964. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
The Douglas-fir beetle (Dendroctonus pseudotsugae Hopkins) can kill large numbers of Douglas-fir trees (Pseudotsuga menziesii (Mirbel) Franco) across a landscape during periods of population outbreaks. High-value individual trees and small stands can be protected from Douglas-fir beetle infestation during outbreaks by applying the anti-aggregation pheromone, MCH (3-methylcyclohex-2-en-1-one). MCH treatments are...
This work combines both applied and basic research regarding previously undescribed relationships between two ecologically and economically important insect groups in coniferous forests, bark beetles (Coleoptera: Curculionidae, Scolytinae) and wild bee (Hymenoptera: Apiformes) communities in Western North America. Across the continent, native bark beetle outbreaks are key drivers of structural...
Three studies on Douglas-fir beetle (DFB), Dendroctonuspseudotsuae, were conducted to investigate its basic and applied biology. Studies included investigations into the spatial relationship of DFB infestations over multiple years and multiple landscapes, relationships between DFB brood adult lipid levels and position of development along the length of tree boles, and...
Douglas-fir beetle, Dendroctonus pseudotsugae Hopk., has caused extensive tree mortality in the North Fork Clearwater River drainage since 1971. In 1974, survey estimates indicated a continued decline in the infestation. Average group size decreased from a high of 158 trees per group in 1971 to 17 in 1974. Average area...
Live western larch, Larix occidentalis Nutt., a tree species resistant to the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, produces the monoterpene 3-carene in higher concentrations compared to Douglas-fir, the preferred host of D. pseudotsugae (Reed et al. 1986). The inhibitory effects on attraction to aggregation pheromones and toxicity of 3-carene to...
Published July 1966. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
The unusually large amount of ice, snow,
and wind-damaged trees that occurred
during the winter of 1996-97 provided prime
habitat for populations of the Douglas-fir
beetle (DFB) (Dendroctonus pseudotsugae)
to build to epidemic numbers. Beetles
emerged during the spring and summer of
1998, attacking hundreds of thousands of
standing Douglas-fir...
A granular controlled release formulation of 2 percent MCH was applied at 4.48 kg/ha to 76.9 ha of uninfested, windthrown Douglas-fir by helicopter with a modified aerial spreader of 1.12 m capacity in May 1982. Douglas-fir beetle population reduction was 96.4 percent by late June. With one exception, treated plots...
The Douglas-fir beetle, Dendroctonus pseudotsugae Hopk., has caused extensive tree mortality for the third consecutive year in the North Fork Clearwater River drainage in northern Idaho. In 1972, the infestation encompassed about 494,080 acres of commercial forest lands in this drainage. It was estimated from a tw-stage aerial photo-ground survey...
I developed a conceptual model of Douglas-fir bark beetle dynamics and associated host mortality across spatial and temporal scales. I proposed that a hierarchy of factors influence host resistance to attack at different spatial scales. I then tested this model by measuring the association between the occurrence of beetle-kill and...
The attack spatial pattern of the Douglas-fir beetle, Dendroctonus
pseudotsugae Hopkins was shown to be regular within a given subarea
of bark on its host, Pseudotsugae menziesii (Mirb.) Franco. Empirical
arguments were advanced which indicated the uniform spacing of attacks
was the result of a beetle controlled spacing mechanism dependent...
Felled second-growth Douglas-fir trees in western Washington were used
to determine the attack distribution and develop a sampling technique
for an endemic Douglas-fir beetle, Dendroctonue peeudotaugae Hopk.
(Coleoptera: Scolytidae) population. The attack density varied by
circumferential position. The lowest density was on the upper bole
and the highest on one...
Published January 1918. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Forests are important to Oregon for their beauty as well as economic value, and Douglas fir trees are among the most common and important in the state. Managing and monitoring Oregon’s forests is imperative to ensure they can remain healthy and productive. One tool that helps forest scientists to understand...
Estimating volume gains in genetically improved stands at rotation age is challenging because first-generation progeny tests in Douglas-fir were typically established to measure the relative growth performance of individual trees from open-pollinated parent trees. The overall goal of this dissertation research was to improve growth simulation of genetically improved Douglas-fir...
Budburst, the initiation of annual growth in plants, is sensitive to climate variation and is therefore used to monitor physiological responses to climate change. Budburst timing can vary between regions of an individual tree, but this phenomenon it is unaccounted for in current monitoring efforts and may contribute to the...
Tissue differentiation of the primary root and its associated
laterals is reported. Secretory elements are the first of the primary
tissues to mature. They appear to be located between the precursory
phloem and pericycle in the primary root, but are more closely
associated with the pericycle in long lateral roots....
The Pacific Coast form of Douglas-fir in natural forest succession
is an intermediate species thriving in the Coast Range and
Cascade Mountains of the Pacific Northwest. This species constitutes
26 percent of the standing timber in the United States, and 24 percent
of the nation's annual timber harvest. Characteristics of...
Mitotic activity in the vascular cambium was determined from
ten samples from a single internode in each of four Douglas-fir
[(Pseudotsuga menziesii (Franco.) Mirb.)]trees. Counts of interphase and mitotic nuclei from nine cores in each sample piece
were averaged and expressed as the frequency and mitotic index.
The sampling error...
Douglas-fir (Pseudotsuga menziesii) has a wide distribution in North America and is one of the tree species most widely distributed outside its natural range. The species has been introduced to Europe, New Zealand, South America, and elsewhere around the world. At present, Douglas-fir is an accepted and integral part of...
To obtain data on the decomposition of the forest floor, a battery operated electrolytic respirometer was developed making it possible to measure CO₂ evolution from field moist forest floor samples in situ independent of root respiration. Banks of four respirometers powered by two 12-volt batteries were installed in three old...