Bionomics of Three Closely Related Species of Contarinia Rond. (Diptera: Cecidomyiidae) from Douglas-fir Needles

1962 ◽  
Vol 94 (4) ◽  
pp. 376-394 ◽  
Author(s):  
S. F. Condrashoff

Incidence of damage to needles of Douglas fir, Pseudotsuga menziesii (Mirb.) Franco, by larvae of gall midges has been noted in British Columbia since 1935. In 1953 severe midge damage to Douglas fir occurred in sections of British Columbia, Washington, Idaho and Montana. Outside of brief and general reference to these gall midges in literature and in unpublished notes, almost nothing was known of their biology, and the species remained undescribed. Relatively little interest has been shown these insects until recent years, when severe infestations in southeastern British Columbia affected the sale of Douglas fir for use as Christmas trees.

1998 ◽  
Vol 28 (8) ◽  
pp. 1198-1206 ◽  
Author(s):  
Paige E Axelrood ◽  
William K Chapman ◽  
Keith A Seifert ◽  
David B Trotter ◽  
Gwen Shrimpton

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.


Author(s):  

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).


Author(s):  

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.


Author(s):  

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.


2018 ◽  
Vol 48 (7) ◽  
pp. 809-820 ◽  
Author(s):  
Neil P. Thompson ◽  
Kathy J. Lewis ◽  
Lisa M. Poirier

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.


2002 ◽  
Vol 134 (5) ◽  
pp. 689-697 ◽  
Author(s):  
P. Morewood ◽  
W.D. Morewood ◽  
R.G. Bennett ◽  
G. Gries

AbstractIn seed orchards of Douglas-fir, Pseudotsuga menziesii (Mirbel) Franco (Pinaceae), located in Washington State and Oregon, United States, we tested whether catches of male Douglas-fir cone gall midges, Contarinia oregonensis Foote, in pheromone-baited traps can be used to predict the extent of galled scales (= seed loss at harvest) caused by developing larvae. In 2000, 27 experimental blocks (4–7 ha each) were selected. In each block we recorded mean numbers of (i) male C. oregonensis captured in 20 pheromone-baited Wing traps, (ii) egg-infested scales in up to 50 conelets in early spring, and (iii) galled scales in up to 50 cones in late summer. In 2001, the experiment was repeated with 20 Delta traps in each of 26 experimental blocks. Moreover, catches of C. oregonensis and nontarget insects in Delta traps and Wing traps were compared in one additional orchard block in 2001. In both years there were positive correlations between mean numbers of egg-infested and galled scales and between mean numbers of captured male C. oregonensis and mean numbers of both egg-infested and galled scales, particularly when only experimental blocks with ≥50% of trees bearing at least 5 conelets were considered. Our results suggest that 4 or 2 captured male C. oregonensis in Wing or Delta traps, respectively, warrant insecticidal control of C. oregonensis. Delta traps, which captured fewer nontarget insects, would be more suitable than Wing traps for operational implementation of this technology.


2010 ◽  
Vol 40 (1) ◽  
pp. 155-166 ◽  
Author(s):  
M. G. Cruickshank ◽  
B. Jaquish ◽  
A. F.L. Nemec

The objectives of this study were to (i) develop a methodology for screening conifer seedlings for resistance to Armillaria ostoyae (Romagn.) Herink and (ii) screen a population of interior Douglas-fir ( Pseudotsuga menziesii var. glauca (Biessn.) Franco) population for resistance to A. ostoyae. Eighteen potted seedlings from each of 86 half-sib interior Douglas-fir families were challenged with inoculum in a 3-year greenhouse trial. The seed originated from four geographically distinct tree breeding zones that represent physically and biologically different environments in southeastern British Columbia. Mortality and the final percent survival of inoculated trees showed differences among the families (survival range 0%–61.1%) and breeding zones (survival range 6.6%–25.3%). Maximum heritability index (0.19) occurred at 28 months. Survival analyses revealed that most of the differences in survival could be explained by the zone from which the family originated. The less susceptible seedlings originated from the drier and warmer zones and limited the spread of the fungus in the root system. Moderate levels of family variation in resistance to A. ostoyae and low-moderate heritability suggest that, in interior Douglas-fir, gains in resistance can be achieved through breeding.


1975 ◽  
Vol 53 (20) ◽  
pp. 2297-2302 ◽  
Author(s):  
A. Funk

Three new species of ascomycetes and two coelomycetes are described from diseased Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) from coastal British Columbia, Canada, viz., Coccomyces pseudotsugae n. sp., Phragmoporthe pseudotsugae n. sp., and Botryosphaeria pseudotsugae n. sp.; Phomopsis portei n. sp. and Haplosporella sp. are associated with the latter two ascomycetes, respectively, and possibly represent their conidial states.


1984 ◽  
Vol 2 (3) ◽  
pp. 93-97
Author(s):  
R.A. Jaynes ◽  
G.R. Stephens ◽  
J.F. Ahrens

Douglas fir, Pseudotsuga Menziesii (Mirb.) Franco, is a popular Christmas tree in the Northeast. In 1976 trees from 11 geographic sources ranging from British Columbia to southern Arizona and New Mexico were planted in a replicated design and managed as a commercial plantation. Information was also obtained on 10 seed sources grown on a commercial tree farm. All sources were hardy in the Connecticut plantings. In general, trees from southern Rocky Mountain sources were bluer, and grew faster than those from northern sources, but they were also more susceptible to attack by Cooley gall aphid, Adelges cooleyi (Gill), and rhabdocline needle cast fungus, Rhabdocline pseudotsugae (Syd.)


Author(s):  

Abstract A new distribution map is provided for Phaeocryptopus gaeumanii (Rohde) Petrak. Hosts: Douglas fir (Pseudotsuga menziesii). Information is given on the geographical distribution in AUSTRALASIA & OCEANIA, Australia (Tasmania), New Zealand, EUROPE, Austria, Belgium, Britain & Northern Ireland, Denmark, France, Germany, Irish Republic, Italy, Netherlands, Romania, Sweden, Switzerland, Yugoslavia, NORTH AMERICA, Canada (British Columbia), USA.


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