DIFFERENTIAL BIOACTIVITY OF CONOPHTHORIN ON FOUR SPECIES OF NORTH AMERICAN BARK BEETLES (COLEOPTERA: SCOLYTIDAE)

2000 ◽  
Vol 132 (5) ◽  
pp. 649-653 ◽  
Author(s):  
Dezene P.W. Huber ◽  
John H. Borden ◽  
Nicole L. Jeans-Williams ◽  
Regine Gries

AbstractThe angiosperm bark volatile, conophthorin, was tested at release rates of 3.0 and 0.3 mg/24 h against the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, the spruce beetle, Dendroctonus rufipennis (Kirby), the pine engraver, Ips pint (Say), and the western balsam bark beetle, Dryocoetes confusus Swaine (all Coleoptera: Scolytidae). The responses of D. pseudotsugae, I. pini, and (in one of two experiments) female D. confusus to attractant-baited traps were disrupted by conophthorin in a dose-dependent manner. Dendroctonus rufipennis was not disrupted by conophthorin. Our results extend the repellent bioactivity of conophthorin to Ips DeGeer spp. and confirm earlier experiments with D. pseudotsugae. Conophthorin may have some utility in protecting susceptible timber from bark beetle attack.

2000 ◽  
Vol 30 (1) ◽  
pp. 50-58 ◽  
Author(s):  
Matthew E Greenwood ◽  
John H Borden

Co-baiting to contain and concentrate the spruce beetle, Dendroctonus rufipennis (Kirby), and the western balsam bark beetle, Dryocoetes confusus Swaine, was investigated at four locations in British Columbia. Two 9-ha areas were established at each location; one was baited and the other left as a control. Single "interior firs," Abies bifolia A. Murray × Abies lasiocarpa (Hook.) Nutt., or groups of two or three trees, were baited with (±)-exo-brevicomin released at 1.0 mg/24 h. "Interior spruces," Picea engelmannii Engelm. ex Parry × Picea glauca (Moench) Voss, were baited with frontalin released at 0.1, 0.6, or 2.5 mg/24 h, or at 0.6 mg/24 h with alpha-pinene, ethanol, or ethyl crotonate. Another experiment investigated possible interspecific interference between D. confusus and D. rufipennis baits. Ratios of currently attacked "green" trees to previously attacked "red" trees for both insects were significantly higher in baited than in control areas, indicating that populations were contained. Baiting, however, did not attract either insect from a zone surrounding each baited area. There was a significant increase in D. confusus attack when two trees instead of one were baited per centre, no increase in D. rufipennis attack when frontalin was released alone or with the potential adjuvants, no effect of frontalin release rates on the percentage of trees attacked by D. rufipennis, and no indication of cross-repellency between baits.


1971 ◽  
Vol 49 (7) ◽  
pp. 1021-1024 ◽  
Author(s):  
T. S. Sahota

The failure of ovarian development in Douglas-fir bark beetles denied of their natural gallery environment and maintained on host bark chips was investigated. Such insects possessed a high activity of proteolytic enzymes in their guts but relatively small amounts of female-specific proteins both in haemolymph and the oocytes. Topical application of farnesyl methyl ether did not increase the activity of gut proteases but resulted in increased amounts of female-specific proteins in haemolymph and ovaries. Thus it appears that the Douglas-fir bark beetles maintained on bark chips do not suffer from an inability to break down the ingested proteins, but synthesize and transfer less than normal amounts of female-specific proteins to the developing oocytes.


2004 ◽  
Vol 136 (3) ◽  
pp. 419-425 ◽  
Author(s):  
N.L. Jeans Williams ◽  
J.H. Borden

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.


The Holocene ◽  
2020 ◽  
Vol 30 (6) ◽  
pp. 847-857 ◽  
Author(s):  
Nick Schafstall ◽  
Niina Kuosmanen ◽  
Christopher J Fettig ◽  
Miloš Knižek ◽  
Jennifer L Clear

Outbreaks of conifer bark beetles in Europe and North America have increased in scale and severity in recent decades. In this study, we identify existing fossil records containing bark beetle remains from the end of the Last Glacial Maximum (~14,000 cal. yr BP) to present day using the online databases Neotoma and BugsCEP and literature searches, and compare these data with modern distribution data of selected tree-killing species. Modern-day observational data from the Global Biodiversity Information Facility (GBIF) database was used to map recorded distributions from AD 1750 to present day. A total of 53 fossil sites containing bark beetle remains, from both geological and archeological sites, were found during our searches. Fossil sites were fewer in Europe ( n = 21) than North America ( n = 32). In Europe, 29% of the samples in which remains were found were younger than 1000 cal. yr BP, while in North America, remains were mainly identified from late Glacial (~14,000–11,500 cal. yr BP) sites. In total, the fossil records contained only 8 of 20 species we consider important tree-killing bark beetles in Europe and North America based on their impacts during the last 100 years. In Europe, Ips sexdentatus was absent from the fossil record. In North America, Dendroctonus adjunctus, Dendroctonus frontalis, Dendroctonus jeffreyi, Dendroctonus pseudotsugae, Dryocoetes confusus, Ips calligraphus, Ips confusus, Ips grandicollis, Ips lecontei, Ips paraconfusus, and Scolytus ventralis were absent. Overall, preserved remains of tree-killing bark beetles are rare in the fossil record. However, by retrieving bulk material from new and existing sites and combining data from identified bark beetle remains with pollen, charcoal, tree rings, and geochemistry, the occurrence and dominance of bark beetles, their outbreaks, and other disturbance events can be reconstructed.


2006 ◽  
Vol 41 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Christopher J. Fettig ◽  
Christopher P. Dabney

Bark beetles (Coleoptera: Scolytidae) are commonly recognized as the most important mortality agent in western coniferous forests. In this study, we describe the abundance of bark beetle predators collected in multiple-funnel traps baited with exo-brevicomin, frontalin and myrcene in northern California during 2003 and 2004. A total of 32,903 Temnochila chlorodia (Mannerheim), 79 Enoclerus lecontei (Wolcott), and 12 E. sphegeus (F.) were collected. The seasonal abundance of E. lecontei and E. sphegeus was not analyzed because too few individuals were collected. In general, T. chlorodia was most abundant in late spring, but a second smaller peak in activity was observed in late summmer. Overall, the ratio of males to females was 0.82. A significant temporal effect was observed in regard to sex ratios with more males collected during later sample periods. Temnochila chlorodia flight activity patterns were similar between years, but activity was generally delayed several weeks in 2003.


2020 ◽  
Vol 55 (3) ◽  
pp. 301-309
Author(s):  
Christopher J. Fettig ◽  
A. Steven Munson ◽  
Donald M. Grosman ◽  
Darren C. Blackford

Abstract Bark beetles are important disturbance agents in coniferous forests, and spruce beetle, Dendroctonus rufipennis (Kirby) (Coleoptera: Curculionidae), is one of the more notable species causing landscape-level tree mortality in western North America. We evaluated the efficacy of bole injections of emamectin benzoate (TREE-äge®; Arborjet Inc., Woburn, MA) alone and combined with propiconazole (Alamo®; Syngenta Crop Protection Inc., Wilmington, DE) for protecting Engelmann spruce, Picea engelmannii Parry ex Engelmann (Pinales: Pinaceae), from mortality attributed to colonization by D. rufipennis. Two injection periods in 2013 (the spring and fall of the year prior to trees first being challenged by D. rufipennis in 2014) and distributions of injection points (7.6- and 15.2-cm spacings) were evaluated. Tree mortality was monitored over a 3-yr period (2014–2017). Emamectin benzoate injected in spring at a narrow spacing (7.6 cm) was the only effective treatment. Two (but not three) field seasons of protection can be expected with a single injection of this treatment. We discuss the implications of these and other results regarding the use of emamectin benzoate and propiconazole for protecting western conifers from mortality attributed to bark beetles, and provide suggestions for future research. A table summarizing the appropriate timing of treatments in different bark beetle/host systems is provided.


2016 ◽  
Vol 113 (46) ◽  
pp. 13075-13080 ◽  
Author(s):  
Rupert Seidl ◽  
Daniel C. Donato ◽  
Kenneth F. Raffa ◽  
Monica G. Turner

Climate change is altering the frequency and severity of forest disturbances such as wildfires and bark beetle outbreaks, thereby increasing the potential for sequential disturbances to interact. Interactions can amplify or dampen disturbances, yet the direction and magnitude of future disturbance interactions are difficult to anticipate because underlying mechanisms remain poorly understood. We tested how variability in postfire forest development affects future susceptibility to bark beetle outbreaks, focusing on mountain pine beetle (Dendroctonus ponderosae) and Douglas-fir beetle (Dendroctonus pseudotsugae) in forests regenerating from the large high-severity fires that affected Yellowstone National Park in Wyoming in 1988. We combined extensive field data on postfire tree regeneration with a well-tested simulation model to assess susceptibility to bark beetle outbreaks over 130 y of stand development. Despite originating from the same fire event, among-stand variation in forest structure was very high and remained considerable for over a century. Thus, simulated emergence of stands susceptible to bark beetles was not temporally synchronized but was protracted by several decades, compared with stand development from spatially homogeneous regeneration. Furthermore, because of fire-mediated variability in forest structure, the habitat connectivity required to support broad-scale outbreaks and amplifying cross-scale feedbacks did not develop until well into the second century after the initial burn. We conclude that variability in tree regeneration after disturbance can dampen and delay future disturbance by breaking spatiotemporal synchrony on the landscape. This highlights the importance of fostering landscape variability in the context of ecosystem management given changing disturbance regimes.


2003 ◽  
Vol 38 (4) ◽  
pp. 602-611 ◽  
Author(s):  
Daniel R. Miller ◽  
John H. Borden

We conducted seven experiments in stands of mature lodgepole pine in southern British Columbia to elucidate the role of host volatiles in the semiochemical ecology of the pine engraver, Ips pini (Say) (Coleoptera: Scolytidae), with particular reference to the behavioral responses of predators and competing species of bark beetles. Our results demonstrated that the attraction of Ips pini and the bark beetle predators Lasconotus complex LeConte (Colydiidae), Thanasimus undatulus (Say) (Cleridae) and a Corticeus sp. (Tenebrionidae) were increased by 3-carene. In contrast, attraction of the bark beetle Pityogenes knechteli Swaine (Scolytidae) to ipsdienol was interrupted by 3-carene and α-pinene. Attraction of L. complex to ipsdienol was increased by γ-terpinene, a compound attractive to the mountain pine beetle, Dendroctonus ponderosae Hopkins (Scolytidae). Terpinolene interrupted the attraction of I. pini to ipsdienol.


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