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.

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.

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.

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.

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.

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.

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.

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

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.

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