A PARTIAL LIFE TABLE FOR THE DOUGLAS-FIR CONE MOTH, BARBARA COLFAXIANA (LEPIDOPTERA: OLETHREUTIDAE)

1977 ◽  
Vol 109 (7) ◽  
pp. 943-951 ◽  
Author(s):  
T. Evan Nebeker
Keyword(s):  
Life Table ◽  
Seed Production ◽  
Critical Factor ◽  
Douglas Fir ◽  
National Forest ◽  
Production Area ◽  
Critical Age

AbstractA population of the Douglas-fir cone moth, Barbara colfaxiana (Kft.), was studied on the Buckhead Seed Production Area, Lowell Ranger District, Willamette National Forest, Oregon, during 1971. Factors contributing to the mortality of B. colfaxiana are presented in a partial life table and discussed. The egg – instar I was identified as the critical age interval and resinosis the critical factor.

CONSUMPTION OF VARIOUS DOUGLAS-FIR CONE STRUCTURES BY BARBARA COLFAXIANA (LEPIDOPTERA: OLETHREUTIDAE)

1977 ◽  
Vol 109 (9) ◽  
pp. 1293-1294
Author(s):  
T. Evan Nebeker
Keyword(s):  
Energy Transfer ◽  
Seed Production ◽  
Energy Budget ◽  
Forest Ecosystem ◽  
Larval Stage ◽  
Douglas Fir ◽  
National Forest ◽  
Larval Instars ◽  
Production Area

During 1971 a study was conducted to determine the amount of the various Douglasfir cone structures (bracts, scales, and seeds) consumed by the Douglas-fir cone moth, Barbara colfaxiana (Kft.), in the Buckhead Seed Production Area, Willamette National Forest, Oregon. It was not the intent of this study to develop a complete energy budget for B. colfaxiana, but rather to determine the number of calories consumed, on the average, by an individual during the larval stage. The behavior of the various larval instars has been discussed by Radcliffe (1952), Keen (1958), Hedlin (1960), and Nebeker (1977). The calorie was selected as the unit of measure due to its usefulness in modeling energy transfer from one component to another in the forest ecosystem.

Black Bears Prefer Urea-Fertilized Trees

1989 ◽  
Vol 4 (1) ◽  
pp. 13-15 ◽  
Author(s):  
E. E. Nelson
Keyword(s):  
Pseudotsuga Menziesii ◽  
Dominant Species ◽  
Tree Mortality ◽  
Ursus Americanus ◽  
Douglas Fir ◽  
Black Bears ◽  
National Forest ◽  
Feeding Damage ◽  
Mount Hood ◽  
The Difference

Abstract Feeding damage by black bears (Ursus americanus) to urea-fertilized 25-yr-old Douglas-firs (Pseudotsuga menziesii) in the Mount Hood National Forest, Oregon, resulted in tree mortality four times as severe as among unfertilized trees. Damage was most apparent following application of urea at 448 kg N/ha in 1972, and 224 kg N/ha in 1977. Only Douglas-fir, the dominant species in the stand, was attacked. Attacked trees were somewhat larger than the stand average, but the difference was not significant. Bears appeared to be attracted to the more vigorous trees, which were on fertilized plots. West. J. Appl. For. 4(1):13-15, January 1989.

Further observations on the pollination mechanism and seed production of Douglas-fir

1982 ◽  
Vol 12 (2) ◽  
pp. 431-434 ◽  
Author(s):  
John N. Owens ◽  
Sheila J. Simpson
Keyword(s):  
Seed Production ◽  
Pollen Grains ◽  
Germination Percentage ◽  
Douglas Fir ◽  
Pollination Mechanism ◽  
Supplemental Pollination

The pollination mechanism of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) was studied. Pollen stained five different colors and applied to the same conelets at five different times showed that the pollen applied on the 1st and 3rd days after conelets became receptive was taken into the micropyle in significantly greater quantities than pollen applied at later dates. A second supplemental pollination did not increase the seed efficiency for individual cones. Seeds produced when an average of less than 1.2 pollen grains were taken into the micropyle had essentially the same germination percentage and proportion of abnormal germinants as seeds resulting when an average of 3.4 or more pollen grains were taken into the micropyle.

Genetic structure and mating system of white spruce (Piceaglauca) in a seed production area

1984 ◽  
Vol 14 (5) ◽  
pp. 639-643 ◽  
Author(s):  
John N. King ◽  
Bruce P. Dancik ◽  
Narinder K. Dhir
Keyword(s):  
Genetic Structure ◽  
Mating System ◽  
Seed Production ◽  
Gel Electrophoresis ◽  
Random Mating ◽  
White Spruce ◽  
Starch Gel Electrophoresis ◽  
Starch Gel ◽  
Production Area ◽  
Mating Model

Embryos and megagametophytes of open-pollinated seed of 37 white spruce (Piceaglauca (Moench) Voss) trees from a seed production area were analyzed by starch gel electrophoresis to determine the genetic structure and mating system over 2 seed crop years. Analysis of four polymorphic enzyme loci (Gdh, Idh, Pgm, and Pgi-2) for spatial and temporal genetic structure and mating system indicated substantial deviations from the random mating model that is assumed when open-pollinated families are designated as half-sibs.

SOIL APPLICATION OF CARBOFURAN TO CONTROL SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE), IN A MANAGED WHITE SPRUCE SEED PRODUCTION AREA

1981 ◽  
Vol 113 (10) ◽  
pp. 949-951 ◽  
Author(s):  
W. H. Fogal ◽  
D. A. Winston ◽  
S. M. Lopushanski ◽  
D. A. MacLeod ◽  
A. J. Willcocks
Keyword(s):  
Seed Production ◽  
Picea Glauca ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
White Spruce ◽  
Cone Production ◽  
Seed Supply ◽  
Current Outbreak ◽  
Production Area ◽  
Production Areas

White spruce, Picea glauca (Moench) Voss, is a major commercial tree species used in reforestation programs throughout Canada, and seed requirements cannot be met in some years because of insect damage and the periodic nature of cone crops. The spruce budworm, Choristoneura fumiferana (Clem.), feeds on buds and cones of its hosts, causing a pronounced decrease in cone production (Schooley 1978). A current outbreak in northeastern Ontario poses a serious threat to white spruce seed supply from high value, managed seed production areas. Therefore, in 1979, we began an experiment to determine whether carbofuran, a systemic insecticide, could be used to protect buds and cones when applied to soil. We chose carbofuran because it has proved successful for control of some insects in seed orchards in the southeastern United States (DeBarr 1978)

scholarly journals Unexpected parasitism of Douglas-fir seed chalcid limits biocontrol options for invasive Douglas-fir in New Zealand

2021 ◽  
Vol 74 (1) ◽  
pp. 70-77
Author(s):  
Sonia Lee ◽  
Simon V. Fowler ◽  
Claudia Lange ◽  
Lindsay A. Smith ◽  
Alison M. Evans
Keyword(s):  
Biological Control ◽  
New Zealand ◽  
Seed Production ◽  
Biocontrol Agent ◽  
Biological Control Agent ◽  
Parasitoid Wasp ◽  
Control Agent ◽  
Douglas Fir ◽  
Seed Predator ◽  
High Level

Douglas-fir seed chalcid (DFSC) Megastigmus spermotrophus, a small (3 mm long) host-specific seed-predatory wasp, was accidentally introduced into New Zealand in the 1920s. Concern over DFSC reducing Douglas-fir seed production in New Zealand led to an attempt at biocontrol in 1955 with the release, but failed establishment, of the small (2.5 mm long) parasitoid wasp, Mesopolobus spermotrophus. We investigated why DFSC causes little destruction of Douglas-fir seed in New Zealand (usually <20%) despite the apparent absence of major natural enemies. Douglas-fir seed collections from 13 New Zealand sites yielded the seed predator (DFSC) but also potential parasitoids, which were identified using morphology and partial COI DNA sequencing. DFSC destroyed only 0.15% of Douglas-fir seed. All parasitoids were identified as the pteromalid wasp, Mes. spermotrophus, the host-specific biocontrol agent released in 1955. Total parasitism was 48.5%, but levels at some sites approached 90%, with some evidence of density-dependence. The discovery of the parasitoid Mes. spermotrophus could indicate that the biocontrol agent released in 1955 did establish after all. Alternatively, Mes. spermotrophus could have arrived accidentally in more recent importations of Douglas-fir seed. The high level of parasitism of DFSC by Mes. spermotrophus is consistent with DFSC being under successful biological control in New Zealand. Suppression of DFSC populations will benefit commercial Douglas-fir seed production in New Zealand, but it also represents the likely loss of a potential biological control agent for wilding Douglas-fir.

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