Co-baiting for spruce beetles, Dendroctonus rufipennis, and western balsam bark beetles, Dryocoetes confusus (Coleoptera: Scolytidae)

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.

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.


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.


2006 ◽  
Vol 36 (11) ◽  
pp. 2974-2982 ◽  
Author(s):  
Dominik Kulakowski ◽  
Thomas T Veblen

In the subalpine forests of the Colorado Rocky Mountains, research on disturbances that have occurred over the past several decades has shown that prior occurrence of disturbances can alter the extent and severity of subsequent disturbances. In the current study, we consider how fire history affected stand susceptibility to a mid-19th century spruce beetle (Dendroctonus rufipennis Kirby 1837) outbreak. Twenty-one sites were randomly located in an Engelmann spruce – subalpine fir (Picea engelmannii Parry ex Engelm. – Abies lasiocarpa (Hook.) Nutt.) forest across ~2000 km2 of the Grand Mesa area, Colorado. At each site, dendrochronological methods were used to reconstruct the history of severe fires and beetle outbreak. Stand-origin dates were estimated by collecting increment cores from 20–27 of the largest trees at each sample site. The beetle outbreak was reconstructed based on coincident releases among nonhost trees that survived the outbreak. Forest stands originated following severe fires in ca. 1790, ca. 1740, and ca. 1700. The 1840's outbreak affected 67% of these stands. Stands that initiated following the ca. 1790 fire were less susceptible to the outbreak than older stands. These findings indicate that stand-replacing fires have mitigated susceptibility to outbreaks of spruce beetles not only during recent outbreaks, but also over the past centuries.


2019 ◽  
Vol 112 (5) ◽  
pp. 2253-2261 ◽  
Author(s):  
E Matthew Hansen ◽  
A Steven Munson ◽  
David Wakarchuk ◽  
Darren C Blackford ◽  
Andrew D Graves ◽  
...  

AbstractWe tested 3-methyl-2-cyclohexen-1-one (MCH) and novel semiochemicals as potential spruce beetle (Dendroctonus rufipennis Kirby) (Coleoptera: Curculionidae, Scolytinae) repellents over multiple years in Utah and Colorado trapping bioassays. MCH is a known spruce beetle repellent and our testing revealed Acer kairomone blend (AKB) and isophorone plus sulcatone as repellents. We subsequently tested these semiochemicals for area and single tree protection to prevent spruce beetle attacks at locations in Utah, Colorado, Wyoming, New Mexico, and Alaska. Individual tree protection trials found MCH–AKB provided significant protection against spruce beetle attacks in the southern Rocky Mountains but not in Alaska. Adding sulcatone or doubling MCH–AKB pouches did not further enhance protection. A degree of protection was extended to spruce at least 10 m distant from the repellents, including in Alaska. Tree diameter was not a significant covariate among treated trees but was positively correlated with the probability of infestation for surrounding spruce. In area protection trials, spruce in control plots were 2.4 times more likely to be in a higher severity attack class compared with spruce in plots treated with MCH–AKB pouches deployed at 30 sets per hectare. Tree diameter had a significant, positive relationship to the probability of infestation. We found MCH–AKB to offer a high degree of protection against beetle attack in Engelmann spruce (Picea engelmannii Parry ex Engelm.) (Pinales: Pinaceae) (Picea engelmannii Parry ex Engelm.) (Pinales: Pinaceae), especially for single tree protection (66% of control trees were strip- or mass-attacked compared with 6% of repellent-treated trees). AKB requires registration and labeling, however, before this economical and environmentally benign semiochemical can be used operationally.


2020 ◽  
Vol 152 (6) ◽  
pp. 790-796
Author(s):  
Thomas Seth Davis

AbstractEngelmann spruce, Picea engelmannii Parry ex Engelm. (Pinaceae), in the southern Rocky Mountains is composed of two distinct phloem monoterpene chemotypes that differ in relative abundances of multiple monoterpenes, particularly α-pinene and Δ3-carene (hereafter, the “α-pinene chemotype” and the “Δ3-carene chemotype”). Here, relative toxicity of these chemotypes is tested on spruce beetle (Dendroctonus rufipennis Kirby) (Coleoptera: Scolytinae), a phloeophagous herbivore that colonises trees of both types. Synthetic monoterpene blends representing each chemotype were tested across a range of concentrations (0, 10, 50, 100, 200, and 500 µg/L) in the lab, and probability of survival of adult beetles exposed to each blend was modelled using a logit function. Logit curves were solved to determine LC25, LC50, and LC75 of each monoterpene blend. On average, probability of beetle survival was lower when exposed to the Δ3-carene chemotype than when exposed to the α-pinene chemotype. However, both chemotypes were completely lethal to beetles at concentrations exceeding 100 µg/L. Adult body mass did not affect survival probability. It is concluded that spruce phloem chemotypes may differ in their toxicity to spruce beetles, with potential consequences for patterns of host-tree colonisation by spruce beetle.


2004 ◽  
Vol 82 (6) ◽  
pp. 735-741 ◽  
Author(s):  
Katherine P Bleiker ◽  
Adnan Uzunovic

Trees with low vigor and reduced radial growth may be more susceptible to attack by bark beetles because of reduced host defenses. Fungi associated with bark beetles may be used to elicit an induced defense response from the host. A blue-stain fungus isolated from Dryocoetes confusus Swaine was used to examine the morphology of the hypersensitive response of fast- and slow-growing subalpine fir trees in British Columbia. Twenty fast-growing and 20 slow-growing trees were inoculated with the blue-stain isolate, and the dimensions of the resultant lesions were compared between fast- and slow-growing trees and between fungus and control treatments at 3, 7, 10, 17, and 41 d after inoculation. The length and width of the lesions was greater in response to fungus versus control treatments at 7, 10, 17, and 41 d after inoculation. The length of the lesions was significantly greater in fast- than in slow-growing trees at 7, 10, and 17 d after inoculation. There was no significant difference in the size of the lesions between fast- and slow-growing trees 41 d after inoculation. The temporary difference in the size of the lesions between fast- and slow-growing trees suggests that host vigor affects the induced defense response within a certain time frame.Key words: Abies lasiocarpa, Dryocoetes confusus, host vigor, defense, blue-stain fungi, Ophiostoma.


1977 ◽  
Vol 55 (8) ◽  
pp. 888-891 ◽  
Author(s):  
H. S. Whitney ◽  
A. Funk

Pezizella chapmanii n.sp. (Helotiales) is described from apothecia found in the galleries of various bark beetles in conifers of western Canada; viz., Dendroctonus rufipennis Kirby galleries in Picea glauca (Moench) Voss; D. ponderosae Hopkins galleries in Pinus contorta var. latifolia Engelmann and in P. ponderosa Laws.; D. murrayanae Hopkins galleries in P. contorta var. latifolia; and D. pseudotsugae Hopkins galleries in Pseudotsuga menziesii (Mirb.) Franco. In agar culture, a prominent Malbranchea conidial state is produced.


2013 ◽  
Vol 145 (4) ◽  
pp. 406-415 ◽  
Author(s):  
K.L. Ryall ◽  
P. Silk ◽  
G.S. Thurston ◽  
T.A. Scarr ◽  
P. de Groot

AbstractFrontalin, seudenol, and a spruce terpene blend are key components of a lure for monitoring spruce beetle, Dendroctonus rufipennis (Kirby) (Coleoptera: Curculionidae: Scolytinae) in eastern Canada, catching the highest number of beetles in several field trials. The standard two-component commercial lure for this species, developed from populations in western North America and composed of 95%:5% (±)-α-pinene and frontalin, failed to elicit attraction to traps in Atlantic Canada; thus a series of trapping experiments were conducted to identify an improved combination of pheromone and host volatiles for this region. Analysis of volatiles from D. rufipennis collected from Newfoundland and Nova Scotia, Canada detected seudenol as an additional female-produced component. Laboratory analysis of the eastern host (Picea glauca (Moench) Voss; Pinaceae) detected the presence of 75%:25% (±)-α-pinene; however, a two-component lure comprised of 75%:25% (±)-α-pinene and frontalin caught no more beetles than an unbaited control. Frontalin and seudenol alone or spruce terpene blend and ethanol alone typically had among the lowest trap catches, but when combined they caught the highest numbers of D. rufipennis, supporting the hypothesis that host volatiles synergise attraction to pheromones. Our results highlight the importance of geographic variation in the response to pheromones and kairomones in this bark beetle.


2006 ◽  
Vol 36 (10) ◽  
pp. 2574-2584 ◽  
Author(s):  
E Matthew Hansen ◽  
Barbara J Bentz ◽  
A Steven Munson ◽  
James C Vandygriff ◽  
David L Turner

Although funnel traps are routinely used to manage bark beetles, little is known regarding the relationship between trap captures and tree mortality near the trap. We conducted a 4 year study in Utah to examine the correlation between funnel-trap captures of spruce beetle (Dendroctonus rufipennis Kirby) and mortality of Engelmann spruce (Picea engelmannii Parry ex Engelm.) within a 10 ha block of the trap. Using recursive partitioning tree analyses, rules were developed for predicting spruce mortality and associated levels of beetle population phase (endemic or epidemic), in the current year and subsequent year, for a given level of trap captures. Although model predictions of infested-stem counts had large variances, our results suggest that funnel-trap captures can be reliably used to estimate relative levels of tree mortality, expressed as spruce beetle population phase. Classification-tree analyses indicate that captures of ~842 spruce beetles during a season (late May to mid-August) from a single funnel trap represent a threshold between endemic (<2 mass-attacked stems/ha) and epidemic conditions (≥2 mass-attacked stems/ha) for either the current or the subsequent year relative to deployment of the funnel trap. Likewise, a lack of infested hosts within 10 m of a funnel trap, also known as spillover, was associated with endemic conditions, whereas trees attacked near the trap correlated with epidemic conditions.


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