Containment and concentration of infestations of the western balsam bark beetle, Dryocoetes confusus (Coleoptera: Scolytidae), using the aggregation pheromone exo-brevicomin

1994 ◽  
Vol 24 (3) ◽  
pp. 483-492 ◽  
Author(s):  
Arthur J. Stock ◽  
J.H. Borden ◽  
T.L. Pratt
Keyword(s):  
Bark Beetle ◽  
Aggregation Pheromone ◽  
Stand Structure ◽  
Nearest Neighbour ◽  
Subalpine Forests ◽  
Subalpine Fir ◽  
Neighbour Distance ◽  
Dryocoetes Confusus ◽  
And Control

Containment and concentration of infestations of the western balsam bark beetle, Dryocoetes confusus Swaine, was demonstrated when (±)-exo-brevicomin released at 0.4 mg/24 h was applied to single subalpine firs, Abieslasiocarpa (Hook.) Nutt., on a 50-m grid over 9-ha blocks, or released at 0.8 mg (24 h/tree)−1 applied to two trees at 50-m centres over the central 4 ha of 16-ha blocks. Nearest-neighbour distance between red trees and newly mass-attacked trees was 24 m in the central 4 ha of baited 16-ha blocks, compared with 13.8 m in control blocks, suggesting a movement of beetles away from "normal" attack centres. Treatments with exo-brevicomin at two trees per spot concentrated 89% of newly mass-attacked trees within 10 m of baited trees, clearly indicating the potential for semiochemical-based management of D. confusus. Within-stand distribution of attacked trees was highly aggregated (Clark–Evans test), in both treated and control blocks. The highly aggregated pattern of attack in control blocks could have been a product of stand structure, and it is hypothesized that D. confusus plays a role in the regeneration of its host by initiating small gaps that favour subalpine fir reproduction. If so, there is potential for using semiochemicals to manipulate D. confusus populations within a patch or selection logging system to maintain cover in climax subalpine forests.

ENDO-BREVICOMIN: AN ANTIAGGREGATION PHEROMONE FOR THE WESTERN BALSAM BARK BEETLE, DRYOCOETES CONFUSUS SWAINE (COLEOPTERA: SCOLYTIDAE)

1990 ◽  
Vol 122 (5) ◽  
pp. 935-940 ◽  
Author(s):  
A.J. Stock ◽  
J.H. Borden ◽  
T.L. Pratt ◽  
H.D. Pierce ◽  
B.D. Johnston
Keyword(s):  
Bark Beetle ◽  
Aggregation Pheromone ◽  
Field Experiments ◽  
Field Tests ◽  
Abies Lasiocarpa ◽  
Subalpine Fir ◽  
Dryocoetes Confusus ◽  
Antiaggregation Pheromone ◽  
High Hazard ◽  
Laboratory Bioassays

AbstractLaboratory bioassays and field tests demonstrated that the (+) enantiomer of endo-brevicomin is an antiaggregation pheromone for the western balsam bark beetle, Dryocoetes confusus Swaine. (+)-endo-Brevicomin significantly reduced the response of beetles of both sexes to the aggregation pheromone exo-brevicomin in laboratory bioassays and in field experiments using multiple-funnel traps. It also prevented attack on subalpine fir, Abies lasiocarpa (Hook) Nutt., trees baited with exo-brevicomin. The (−) enantiomer of endo-brevicomin was inactive. These results suggest that (+) or (±)-endo-brevicomin has potential for protecting selected trees from attack, or suppressing western balsam bark beetle activity in high hazard or infested stands.

Response of Dryocoetes confusus and D. autographus (Coleoptera: Scolytidae) to enantiospecific pheromone baits

2004 ◽  
Vol 136 (3) ◽  
pp. 419-425 ◽  
Author(s):  
N.L. Jeans Williams ◽  
J.H. Borden
Keyword(s):  
Bark Beetle ◽  
Aggregation Pheromone ◽  
Bark Beetles ◽  
Field Studies ◽  
Pheromone Component ◽  
Male And Female ◽  
Dryocoetes Confusus

AbstractIn past field studies, the greatest response of western balsam bark beetles, Dryocoetes confusus Swaine, to traps was obtained with blends of (+)-exo-brevicomin and (+)- or (±)-endo-brevicomin, which imitate the natural male-produced aggregation pheromone. We conducted a trapping experiment comparing low-release enanti ospecific blends (9:1 (+)-exo-brevicomin:(+)-endo-brevicomin or 9:2 (+)-exo-brevicomin:(±)-endo-brevicomin released at 0.3, 0.1, or 0.03 mg per day) with the standard commercial (±)-exo-brevicomin bait released at 1.2 mg per day. Multiple-funnel traps baited with the experimental blends caught more D. confusus than the unbaited traps, but only traps with the 9:2 (+):(±) blend released at 0.3 and 0.03 mg per day caught significantly more male and female beetles than those baited with the standard bait. Thus, trap sensitivity can be improved with the addition of (±)-endo-brevicomin. The sympatric bark beetle D. autographus Ratzeburg was captured in significant numbers in traps baited with (±)-exo-brevicomin. A subsequent trapping experiment showed that D. autographus responded to (+)- or (±)-exo-brevicomin, but not to (−)-exo-brevicomin, suggesting that (+)-exo-brevicomin is the principal aggregation pheromone component in this species.

scholarly journals Effects of Western Balsam Bark Beetle on Spruce-Fir Forests of North-Central Wyoming

2003 ◽  
Vol 18 (4) ◽  
pp. 259-266 ◽  
Author(s):  
Joel D. McMillin ◽  
Kurt K. Allen ◽  
Daniel F. Long ◽  
Jeri Lyn Harris ◽  
José F. Negrón
Keyword(s):  
Bark Beetle ◽  
Basal Area ◽  
Stand Density ◽  
Herbaceous Plant ◽  
North Central ◽  
Subalpine Fir ◽  
Dryocoetes Confusus ◽  
Density Index ◽  
Stand Density Index ◽  
Stand Conditions

Abstract Western balsam bark beetle, Dryocoetes confusus (Coleoptera: Scolytidae), has caused widespread mortality of subalpine fir (Abies lasiocarpa) in western North America throughout the past decade. The objectives of this study were to document the effects of this mortality, relate mortality to pre-existing stand conditions, and investigate the role of storm-damaged fir in beetle population dynamics in north-central Wyoming. Transect cruise lines and pairs of infested and uninfested plots were installed to detect changes in the forest overstory and understory and to determine associations between stand conditions and beetle-caused fir mortality. On average, beetles killed more than 70 trees/ac over the last several years. This mortality resulted in significant decreases in: subalpine fir basal area, trees per acre, stand density index, and the percentage of subalpine fir stems in the overstory. Small, but significant increases were detected in the understory; herbaceous plant abundance increased in the infested plots compared with the noninfested plots. Moreover, significant positive linear relationships were found between the amount of fir mortality and the percentage of subalpine fir trees in a stand, subalpine fir basal area, and subalpine fir stand density index. In addition, a significant positive linear relationship was found between the percentage of wind-caused downed fir logs in an area and the percentage of logs utilized by western balsam bark beetle. The blowdown events that occurred in the mid-1990s in combination with a high percentage of fir component has provided ideal conditions for continued beetle expansion. West. J. Appl. For. 18(4):259–266.

scholarly journals Evaluation of Two Pheromone Baits for Containment and Concentration of Attack by the Western Balsam Bark Beetle, Dryocoetes confusus (Coleoptera: Curculionidae)

2006 ◽  
Vol 21 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Nicole L. Jeans-Williams ◽  
John H. Borden
Keyword(s):  
Bark Beetle ◽  
Aggregation Pheromone ◽  
Management Tools ◽  
Stand Management ◽  
Dryocoetes Confusus

Abstract In past studies, the greatest response by the western balsam bark beetle Dryocoetes confusus Swaine (Coleoptera: Scolytidae) to traps and baited trees was obtained with blend of (+)-exo- and (±)-endo-brevicomin, which mimic the natural male-produced aggregation pheromone. We conducted a tree-baiting experiment to determine whether low-release enantiospecific blends [9:1 (+) exo-brevicomin:(+)-endo-brevicomin, or 9:2 (+)-exo-brevicomin: (±)-endo-brevicomin released at 0.3, 0.1, or 0.03 mg/day] could compete with or improve the efficacy of the standard (±)-exo-brevicomin bait released at 1.2 mg/day. In this experiment, the standard and experimental baits were almost 90% effective in inducing attack by D. confusus. Two subsequent 9-ha block experiments compared the ability of the standard and 9:2 (+)-exo-brevicomin:(±)-endo-brevicomin baits to contain and concentrate infestations before harvesting. Again, both baits were equally effective as potential stand management tools based on almost 100% attack on baited trees, green-to-red tree ratios between 3:1 and 5:1, and redistribution of the majority of attack around baited rather than red trees from which beetles could emerge. We recommend that the standard bait continue to be offered commercially for treatment of stands infested by D. confusus.

Characteristics of subalpine fir susceptible to attack by western balsam bark beetle (Coleoptera: Scolytidae)

2003 ◽  
Vol 33 (8) ◽  
pp. 1538-1543 ◽  
Author(s):  
Katherine P Bleiker ◽  
B Staffan Lindgren ◽  
Lorraine E Maclauchlan
Keyword(s):  
Bark Beetle ◽  
Diameter Distribution ◽  
Lower Percentage ◽  
Abies Lasiocarpa ◽  
Subalpine Fir ◽  
Dryocoetes Confusus ◽  
Crown Volume ◽  
The Mean ◽  
Rating Model ◽  
Tree Characteristics

A diameter distribution survey at three sites in the interior of British Columbia revealed that the western balsam bark beetle (Dryocoetes confusus Swaine) predominately attacked trees from the three to four largest diameter classes at each site. However, the mean diameter of attacked trees was significantly different among sites, indicating that factors other than diameter contribute to the susceptibility of subalpine fir (Abies lasiocarpa (Hook.) Nutt.) to the western balsam bark beetle. A number of tree characteristics, including measures of growth, age, crown size, and phloem thickness, were compared among a total of 22 successfully attacked, 26 unsuccessfully attacked, and 28 unattacked trees at three sites. Of the 12 tree characteristics measured, five showed significant differences between successfully attacked and unattacked trees. Successfully attacked trees had a lower percentage of the bole covered with constant crown, lower crown volume, lower radial growth in the last 5 years, and were older than unattacked trees. Successfully attacked trees also produced less induced resinosis than unsuccessfully attacked trees. The results of this study suggest that western balsam bark beetle mortality may be limited by the presence and distribution of susceptible hosts. The study also identifies a number of variables that could be used in a susceptibility and risk rating model for western balsam bark beetle.

Conifer snagfall data in bark-beetle infested subalpine forests at the Fraser Experimental Forest, Colorado, USA

2019 ◽  
Author(s):  
Charles C. Rhoades ◽  
Robert M. Hubbard ◽  
Paul R. Hood ◽  
Banning J. Starr ◽  
Daniel B. Tinker ◽  
...  
Keyword(s):  
Bark Beetle ◽  
Subalpine Forests

ELASTIC PROPERTIES OF STRAINED FCC AND HCP IRON

1993 ◽  
Vol 07 (01n03) ◽  
pp. 207-211
Author(s):  
T. KRAFT ◽  
M. METHFESSEL ◽  
M. VAN SCHILFGAARDE ◽  
M. SCHEFFLER
Keyword(s):  
Energy Cost ◽  
Interplanar Distance ◽  
Orbital Method ◽  
Full Potential ◽  
Local Spin Density Approximation ◽  
Nearest Neighbour ◽  
Density Approximation ◽  
Neighbour Distance ◽  
Large Lattice ◽  
Fcc Phase

Using the full-potential linear muffin-tin orbital method within the local spin-density approximation we analyse the influence of the nearest neighbour distance on fcc(111) or hcp(0001) iron layers. The LDA-LSDA error in describing ferromagnetic phases is determined to be at least 15 mRy/atom. As a consequence of this error, our calculations favour paramagnetic ground states. In this sense, the reported results have some model character. However, our analysis of the elastic energy cost under distortions should hold for transition metals in general. Allowing relaxations of the interplanar distance the fcc phase can become energetically favourable over the hcp phase at large lattice mismatches. The main reason for this behaviour is the enhanced stiffness of the hcp interplanar bonds due to the shortening of the axial c/a ratio.

Semiochemicals produced by western balsam bark beetle,Dryocoetes confusus Swaine (Coleoptera: Scolytidae)

1987 ◽  
Vol 13 (4) ◽  
pp. 823-836 ◽  
Author(s):  
J. H. Borden ◽  
A. M. Pierce ◽  
H. D. Pierce ◽  
L. J. Chong ◽  
A. J. Stock ◽  
...  
Keyword(s):  
Bark Beetle ◽  
Dryocoetes Confusus

scholarly journals Stand Structure and Composition 32 Years after Precommercial Thinning Treatments in a Mixed Northern Conifer Stand in Central Maine

2011 ◽  
Vol 28 (2) ◽  
pp. 92-96 ◽  
Author(s):  
Aaron R. Weiskittel ◽  
Laura S. Kenefic ◽  
Rongxia Li ◽  
John Brissette
Keyword(s):  
Stand Structure ◽  
Abies Balsamea ◽  
Basal Area ◽  
Long Term Effects ◽  
Mixed Species ◽  
Precommercial Thinning ◽  
Large Trees ◽  
Stand Attributes ◽  
And Control

Abstract The effects of four precommercial thinning (PCT) treatments on an even-aged northern conifer stand in Maine were investigated by examining stand structure and composition 32 years after treatment. Replicated treatments applied in 1976 included: (1) control (no PCT), (2) row thinning (rowthin; 5-ft-wide row removal with 3-ft-wide residual strips), (3) row thinning with crop tree release (rowthin+CTR; 5-ft-wide row removal with crop tree release at 8-ft intervals in 3-ft-wide residual strips), and (4) crop tree release (CTR; release of selected crop trees at 8×8-ft intervals). PCT plots had more large trees and fewer small trees than the control in 2008. There were no other significant differences between the rowthin and control. The rowthin+CTR and CTR treatments had lower total and hardwood basal area (BA) and higher merchantable conifer BA than the control. CTR also resulted in more red spruce (Picea rubens [Sarg.]) and less balsam fir (Abies balsamea [L.]) than the other treatments. Although stand structures for rowthin+CTR and CTR were similar, the percentage of spruce in CTR was greater. Although the less-intensive rowthin+CTR treatment may provide many of the same benefits as CTR, the latter would be the preferred treatment if increasing the spruce component of a stand is an objective. Overall, early thinning treatments were found to have long-term effects on key stand attributes, even more than 30 years after treatment in areas with mixed species composition and moderate site potential.

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