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.

SECONDARY ATTRACTION IN THE WESTERN BALSAM BARK BEETLE, DRYOCOETES CONFUSUS (COLEOPTERA: SCOLYTIDAE)

1983 ◽  
Vol 115 (5) ◽  
pp. 539-550 ◽  
Author(s):  
A. J. Stock ◽  
J. H. Borden
Keyword(s):  
Bark Beetle ◽  
Field Experiments ◽  
Abies Lasiocarpa ◽  
Extraction Techniques ◽  
Dryocoetes Confusus ◽  
Male Attractant ◽  
Antiaggregation Pheromone ◽  
Primary Attraction ◽  
Laboratory Bioassays ◽  
Secondary Attraction

AbstractEvidence for secondary attraction in the western balsam bark beetle, Dryocoetes confusus Swaine, was obtained in laboratory bioassays and field experiments. Both sexes showed positive responses to volatiles of the host tree, Abies lasiocarpa (Hook.) Nutt., indicating that primary attraction is probably important in host selection by this species. Male beetles initiated attack and within 6 h produced an aggregation pheromone(s), which was present in frass and in pentane extracts of the abdomens of males excised from logs. Both sexes responded to the pheromone. Abdominal extract of unmated males which had bored into host bark for 14 days was still attractive. Pheromone production was induced by exposing males to host resin volatiles. Mating had no effect on male attractiveness, but induced females to produce an antiaggregation pheromone which, in laboratory bioassays, at least partially inhibited response to male attractant. The attractive volatiles from male-infested logs were successfully captured on Porapak Q®. The development of laboratory bioassay and pheromone extraction techniques indicates that a pheromone isolation program is feasible.

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.

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.

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.

PATHOGENIC FUNGI ASSOCIATED WITH A BARK BEETLE ON ALPINE FIR

1965 ◽  
Vol 43 (5) ◽  
pp. 563-570 ◽  
Author(s):  
A. C. Molnar
Keyword(s):  
Bark Beetle ◽  
Pathogenic Fungi ◽  
The Other ◽  
Blue Staining ◽  
Abies Lasiocarpa ◽  
Decay Fungi ◽  
Inner Bark ◽  
Dryocoetes Confusus

Unexplained mortality associated with attacks of the western balsam bark beetle (Dryocoetes confusus Sw.) in alpine fir (Abies lasiocarpa (Hook.) Nutt.) was found to be caused by a beetle–fungus complex. Not all trees attacked were killed, but surviving trees were left with lesions which provided potential entrance courts for decay fungi. Four closely related fungi, isolated from necrotic lesions centered at beetle bore holes, were shown by inoculation to be pathogenic. Ceratocystis dryocoetidis Kendrick and Molnar was the most virulent of these fungi on the basis of the size of lesions produced. C. dryocoetidis caused cambial and inner bark necrosis, while the other three fungi produced necrosis and blue staining of the sapwood.

RESPONSE OF THE WESTERN BALSAM BARK BEETLE, DRYOCOETES CONFUSUS SWAINE (COLEOPTERA: SCOLYTIDAE), TO HOST TREES BAITED WITH ENANTIOSPECIFIC BLENDS OF EXO- AND ENDO-BREVICOMIN

1994 ◽  
Vol 126 (1) ◽  
pp. 43-48 ◽  
Author(s):  
Alejandro D. Camacho ◽  
John H. Borden
Keyword(s):  
British Columbia ◽  
Bark Beetle ◽  
Abies Lasiocarpa ◽  
Dryocoetes Confusus ◽  
Host Trees

AbstractThe response of the western balsam bark beetle, Dryocoetes confusus Swaine, to subalpine firs, Abies lasiocarpa (Hook.) Nutt., baited with (±)-exo-brevicomin (EXOB) or 9:1 blends of EXOB and endo-brevicomin (ENDOB), in two chiral combinations: (+):(±) and (+):(+), was assessed in a heavily infested stand in British Columbia. Unbaited control trees were not attacked, and the proportion of mass-attacked baited trees was similar for all other treatments. However, trees baited with the (+):(+) blend had the highest number of attacks per square metre, and they were also surrounded by the most attacked trees. The (+):(±) blend was intermediate in attractancy, and (±)EXOB was the least attractive bait. Pheromone-based management of D. confusus infestations may be more effective with the 9:1 blend of (+)EXOB:(+)ENDOB than with the previously used (±)EXOB baits.

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.

ENANTIOMERIC COMPOSITION AND RELEASE RATES OF exo-BREVICOMIN INFLUENCE AGGREGATION OF THE WESTERN BALSAM BARK BEETLE, DRYOCOETES CONFUSUS SWAINE (COLEOPTERA: SCOLYTIDAE)

1995 ◽  
Vol 127 (4) ◽  
pp. 449-456 ◽  
Author(s):  
Arthur J. Stock ◽  
J.H. Borden ◽  
T.L. Pratt ◽  
H.D. Pierce ◽  
B.D. Johnston
Keyword(s):  
Bark Beetle ◽  
Field Experiments ◽  
Enantiomeric Composition ◽  
Release Rates ◽  
Dryocoetes Confusus ◽  
Better Than

AbstractField experiments demonstrated that the western balsam bark beetle, Dryocoetes confusus, responded best to multiple-funnel traps baited with mixtures of (+)- and (−)-exo-brevicomin. (±)-exo-Brevicomin released at 0.8 mg per 24 h performed as well as or better than release rates of from 0.2 to 1.0 mg per 24 h in terms of the number of baited trees which were mass attacked (80%), average attack density, and average number of trees attacked within a 10-m radius of baited trees. Baiting more than one tree in a spot resulted in an intensification of attack on baited trees and increased the number of trees attacked within 10 m of each spot.

A NEW CERATOCYSTIS AND ITS VERTICICLADIELLA IMPERFECT STATE ASSOCIATED WITH THE BARK BEETLE DRYOCOETES CONFUSUS ON ABIES LASIOCARPA

1965 ◽  
Vol 43 (1) ◽  
pp. 39-43 ◽  
Author(s):  
W. Bryce Kendrick ◽  
A. C. Molnar
Keyword(s):  
Bark Beetle ◽  
Abies Lasiocarpa ◽  
Conidial State ◽  
Dryocoetes Confusus ◽  
Imperfect State

A new Ceratocystis and its Verticicladiella conidial state are described and illustrated. This fungus has been frequently isolated from necrotic lesions associated with attacks by the bark beetle Dryocoetes confusus on Abies lasiocarpa, and is believed to be an important pathogen.

THE FUNGUS BEAUVERIA BASSIANA (DEUTEROMYCOTINA: HYPHOMYCETACEAE) IN THE WESTERN BALSAM BARK BEETLE, DRYOCOETES CONFUSUS (COLEOPTERA: SCOLYTIDAE)

1984 ◽  
Vol 116 (10) ◽  
pp. 1419-1424 ◽  
Author(s):  
H. S. Whitney ◽  
D. C. Ritchie ◽  
J. H. Borden ◽  
A. J. Stock
Keyword(s):  
British Columbia ◽  
Beauveria Bassiana ◽  
Bark Beetle ◽  
Natural Occurrence ◽  
Abies Lasiocarpa ◽  
Direct Observations ◽  
Dryocoetes Confusus ◽  
Fungus Beauveria Bassiana ◽  
Healthy Males

AbstractThe natural occurrence of beauveriosis in Dryocoetes confusus (Swaine) in Abies lasiocarpa (Hook.) Nutt. in British Columbia is reported, and the pathogenicity of Beauveria bassiana (Bals.) Vuill. isolated from D. confusus was confirmed experimentally. Also, direct observations of newly established pairs of D. confusus in glass – phloem sandwich cultures showed that cadavers of B. bassiana-killed females were walled-off with frass by healthy males.

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