ABUNDANCE OF THE FIR ENGRAVER, SCOLYTUS VENTRALIS, AND THE DOUGLAS-FIR BEETLE, DENDROCTONUS PSEUDOTSUGAE, FOLLOWING TREE DEFOLIATION BY THE DOUGLAS-FIR TUSSOCK MOTH, ORGYIA PSEUDOTSUGATA

1984 ◽  
Vol 116 (3) ◽  
pp. 293-305 ◽  
Author(s):  
L. C. Wright ◽  
A. A. Berryman ◽  
B. E. Wickman
Keyword(s):  
Bark Beetles ◽  
Female Parent ◽  
Douglas Fir ◽  
Mortality Factors ◽  
Dendroctonus Pseudotsugae ◽  
Tussock Moth ◽  
Orgyia Pseudotsugata ◽  
Tree Defoliation ◽  
Key Factor ◽  
Adult Dispersal

AbstractFir engraver and Douglas-fir beetle numbers were monitored during and after an outbreak of the Douglas-fir tussock moth. The population behavior of the two species of bark beetles was similar. Number of emerged offspring/female was highest during the years of defoliation and declined afterward. Total number of beetle attacks peaked 1 to 2 years after defoliation ended and then declined. During and 1 year after defoliation, beetles generally infested trees that had greater than 90% defoliation. After this time infestations were not as strongly associated with heavily defoliated trees. Life tables were constructed for beetles within trees and for beetles per area of forest land. Key mortality factors acting on beetles within trees occurred during the larval and pupal stages. Mortality during adult dispersal was a key factor when beetle density per area of land was considered. Although beetle offspring emerging per dm2 of bark surface was relatively low in defoliated trees, defoliation appeared to reduce host resistance which enabled beetles to successfully attack at lower densities, reducing intraspecific competition, and resulting in increased emergence of offspring/female parent.

Failure of ovarian development in the Douglas-fir bark beetle, Dendroctonus pseudotsugae; an analysis of gut proteases and female-specific proteins

1971 ◽  
Vol 49 (7) ◽  
pp. 1021-1024 ◽  
Author(s):  
T. S. Sahota
Keyword(s):  
High Activity ◽  
Bark Beetle ◽  
Methyl Ether ◽  
Bark Beetles ◽  
Ovarian Development ◽  
Proteolytic Enzymes ◽  
Douglas Fir ◽  
Dendroctonus Pseudotsugae ◽  
Specific Proteins ◽  
Female Specific

The failure of ovarian development in Douglas-fir bark beetles denied of their natural gallery environment and maintained on host bark chips was investigated. Such insects possessed a high activity of proteolytic enzymes in their guts but relatively small amounts of female-specific proteins both in haemolymph and the oocytes. Topical application of farnesyl methyl ether did not increase the activity of gut proteases but resulted in increased amounts of female-specific proteins in haemolymph and ovaries. Thus it appears that the Douglas-fir bark beetles maintained on bark chips do not suffer from an inability to break down the ingested proteins, but synthesize and transfer less than normal amounts of female-specific proteins to the developing oocytes.

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.

ATTACK BY GNATHOTRICHUS SULCATUS (COLEOPTERA: SCOLYTIDAE) ON STUMPS AND FELLED TREES BAITED WITH SULCATOL AND ETHANOL

1977 ◽  
Vol 109 (5) ◽  
pp. 675-686 ◽  
Author(s):  
J. A. McLean ◽  
J. H. Borden
Keyword(s):  
Bark Beetles ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Systemic Insecticide ◽  
Dendroctonus Pseudotsugae ◽  
University Of British Columbia ◽  
Steady Decrease ◽  
Population Aggregation ◽  
The University

AbstractEthanol and sulcatol (6-methyl-5-hepten-2-ol), primary attractant and population aggregation pheromone, respectively, for Gnathotrichus sulcatus, were deployed alone or in combination on stumps and felled trees in the University of British Columbia Research Forest, Maple Ridge, B.C. On 18 April 1974, four Douglas-fir trees were felled at each of three locations, and four western hemlock trees were felled at each of three other locations. Felled trees and their respective stumps were baited on 26 April. Attacks by G. sulcatus and bark beetles were recorded at weekly intervals until 25 October. G. sulcatus attacks increased rapidly, reaching a maximum in June and July, followed by a steady decrease to October. Attacks by Dendroctonus pseudotsugae, Pseudohylesinus nebulosus, and P. tsugae showed characteristic seasonal trends, but were not correlated to any of the treatments. Over half the G. sulcatus attacks were on stumps, in which attack densities reached 683.5/m2. The greatest numbers of attacks were on stumps and logs baited with sulcatol or sulcatol plus ethanol. There was a significant interaction between sulcatol and ethanol on Douglas-fir but not on western hemlock. Significantly more G. sulcatus attacked ethanol-baited western hemlock stumps and logs than unbaited controls. However, there was no difference between the level of attack on ethanol-baited Douglas-fir and the controls. The role of ethanol is hypothesized to be more of a boring stimulant than a major attractant. Stumps baited with sulcatol and then treated with ethanolic solutions of systemic insecticide could be used to trap and kill field populations, thus reducing numbers of G. sulcatus being transported to log-booming grounds, dryland sorting areas, and sawmills.

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.

THE EFFECT OF TEMPERATURE AND FOOD DEPRIVATION ON SURVIVAL OF FIRST-INSTAR DOUGLAS-FIR TUSSOCK MOTHS (ORGYIA PSEUDOTSUGATA) (LEPIDOPTERA: LYMANTRIIDAE)

1983 ◽  
Vol 115 (6) ◽  
pp. 663-666 ◽  
Author(s):  
Roy C. Beckwith
Keyword(s):  
Food Deprivation ◽  
Larval Survival ◽  
Douglas Fir ◽  
Effect Of Temperature ◽  
Rearing Temperature ◽  
Tussock Moth ◽  
Orgyia Pseudotsugata ◽  
First Instar ◽  
Starvation Conditions

AbstractMortality of neonatal Douglas-fir tussock moth larvae varied from 0% to 100% depending on the rearing temperature and duration of food deprivation. Lower temperatures apparently favor larval survival under starvation conditions. For each period of food deprivation, mortality occurs earlier as the temperature increases; this shift to earlier mortality was significant at P <.01. Some implications are discussed.

The Life History and Habits of Scolytus unispinosus Leconte (Coleoptera: Scolytidae) in the Interior of British Columbia

1962 ◽  
Vol 94 (1) ◽  
pp. 17-25 ◽  
Author(s):  
L. H. McMullen ◽  
M. D. Atkins
Keyword(s):  
British Columbia ◽  
Bark Beetles ◽  
Pacific Coast ◽  
Rocky Mountain ◽  
Economic Importance ◽  
Douglas Fir ◽  
Dendroctonus Pseudotsugae ◽  
Rocky Mountain Region ◽  
The Pacific ◽  
Standing Timber

The Douglas-fir engraver, Scolytus unispinosus Leconte, is a common bark beetle throughout the Pacific Coast and Rocky Mountain Region of North America. Although it occasionally kills young trees (Chamberlin, 1939), it is of minor economic importance, usually confining its attack to tops, limbs and logging slash. In standing timber it acts primarily as a secondary insect, attacking the tops and branches of trees killed or severely weakened by other agents. In the interior of British Columbia it is commonly found in Douglas fir, Pseudotsuga menziesii (Mirb.) Franco, and thus it is of interest as an associate of the Douglas-fir beetle, Dendroctonus pseudotsugae Hopk. Two other bark beetles Pseudohylesinus nebulosus (Leconte) and Scolytus tsugae (Swaine) with similar associations were studied earlier (Walters and McMullen, 1956; McMullen and Atkins, 1959).

On the Flight and Host Selection of the Douglas-fir Beetle, Dendroctonus pseudotsugae Hopk. (Coleoptera: Scolytidae)

1962 ◽  
Vol 94 (12) ◽  
pp. 1309-1325 ◽  
Author(s):  
L. H. McMullen ◽  
M. D. Atkins
Keyword(s):  
Experimental Data ◽  
Life Cycle ◽  
Host Selection ◽  
Bark Beetles ◽  
Time Of Flight ◽  
Field Studies ◽  
Douglas Fir ◽  
Major Portion ◽  
Dendroctonus Pseudotsugae ◽  
Selection Of

The flight of bark beetles covers a short but important period of their life cycle, during which they are exposed to conditions not encountered during the major portion of their life under the bark. The time of flight and the factors which affect it are important, not only to the dispersal and survival of the insect, but also in the interpretation of experimental data dependent upon the beetle's flight activity.Chapman (1954), Rudinsky and Vité (1956), and Atkins (1959, 1960, 1961) studied the flight of the Douglas-fir beetle under laboratory conditions, but there is scant reference to field studies on the flight of this insect. Chapman and Kinghorn (1958) recorded the number caught in window flight traps near Cowichan Lake, B.C., and unpublished reports describe emergence records obtained from cage studies conducted near Lumby, B.C.

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