Publications

effects of permethrin on aquatic organisms in a freshwater stream in south-central alaska.	permethrin (0.5%) was applied to individual lutz spruce, picea x lutzii little, to protect them from attack by spruce beetles, dendroctonus rufipennis (kirby). residue levels were monitored in a freshwater stream above, adjacent to, and below the treatment site at intervals before, during, and after treatment. maximum residue levels in the stream within the treatment site ranged from 0.05 +/- 0.01 ppb 5 h after treatment to 0.14 +/- 0.03 ppb 8-11 h after treatment, with a decrease to 0.02 +/- 0. ...	1992	1619107
transformation of presumptive precursors to frontalin and exo-brevicomin by bark beetles and west indian sugarcane weevil (coleoptera).	(z)-6-nonen-2-one (1) has recently been shown to be the biosynthetic precursor for the aggregation pheromone exo-brevicomin (2) in mountain pine beetle (mpb) males, dendroctonus ponderosae (hopkins). we tested the hypotheses that (1) 6-methyl-6-hepten-2-one (3) is the biosynthetic precursor for the aggregation pheromone frontalin (4) in the spruce beetle (sb), dendroctonus rufipennis (kirby), and (2) that frontalin and exo-brevicomin are produced from 3 and 1, respectively, only by beetles that ...	1996	8733625
mch released in a novel pheromone dispenser prevents spruce beetle, dendroctonus rufipennis (coleoptera: scolytidae), attacks in south-central alaska.	field tests of 3-methyl-2-cyclohexen-1-one (mch), the antiaggregation pheromone of the spruce beetle, dendroctonus rufipennis kirby, were conducted in south-central alaska in stands of lutz spruce, picea x lutzii little, and sitka spruce, p. sitchensis (bong.) carr. the deployment of mch in a novel releaser significantly reduced trap catches and spruce beetle attacks on standing live spruce by 96 and 87%, respectively. the results of this study demonstrate the first successful field test of mch ...	2003	12650341
phloeophagous and predaceous insects responding to synthetic pheromones of bark beetles inhabiting white spruce stands in the great lakes region.	tree killing and saprophytic bark beetles exert important ecological and economic roles in north american spruce forests. chemical signaling among bark beetles, and responses by associate insects such as predators and competitors, have significant effects on the population dynamics and ecology of this community. synthetic pheromones of primary (tree killing) and secondary (saprophytic) bark beetle species and blank controls were tested using multiple funnel and lower stem flight traps in white s ...	2003	12921443
comparison of naturally and synthetically baited spruce beetle trapping systems in the central rocky mountains.	we compared naturally baited trapping systems to synthetically baited funnel traps and fallen trap trees for suppressing preoutbreak spruce beetle, dendroctonus rufipennis kirby, populations. lures for the traps were fresh spruce (picea spp.) bolts or bark sections, augmented by adding female spruce beetles to create secondary attraction. in 2003, we compared a naturally baited system ("bolt trap") with fallen trap trees and with synthetically baited funnel traps. trap performance was evaluated ...	2006	16686135
effectiveness of bifenthrin (onyx) and carbaryl (sevin sl) for protecting individual, high-value conifers from bark beetle attack (coleoptera: curculionidae: scolytinae) in the western united states.	high-value trees, such as those located in residential, recreational, or administrative sites, are particularly susceptible to bark beetle (coleoptera: curculionidae: scolytinae) attack as a result of increased amounts of stress associated with drought, soil compaction, mechanical injury, or vandalism. tree losses in these unique environments generally have a substantial impact. the value of these individual trees, cost of removal, and loss of esthetics may justify protection until the main thru ...	2006	17066800
changing forest disturbance regimes and risk perceptions in homer, alaska.	forest disturbances caused by insects can lead to other disturbances, risks, and changes across landscapes. evaluating the human dimensions of such disturbances furthers understanding of integrated changes in natural and social systems. this article examines the effects of changing forest disturbance regimes on local risk perceptions and attitudes in homer, alaska. homer experienced a spruce bark beetle (dendroctonus rufipennis) outbreak with large-scale tree mortality and a 5,000-acre fire in 2 ...	2007	18093055
phylogeography of spruce beetles (dendroctonus rufipennis kirby) (curculionidae: scolytinae) in north america.	tree-feeding insects that are widespread in north temperate regions are excellent models for studying how past glaciations have impacted differentiation and speciation. we used mitochondrial dna (mtdna) sequences and allele frequencies at nine microsatellite loci to examine genetic population structure across the current range of the spruce beetle (dendroctonus rufipennis), an economically important insect in north america. two major haplotype groups occur across northern north america, from new ...	2007	17561913
an evaluation of british columbian beetle-killed hybrid spruce for bioethanol production.	the development of bioconversion technologies for production of fuels, chemicals, and power from renewable resources is currently a high priority for developed nations such as the united states, canada, and the european union as a way to improve national energy security and reduce greenhouse gas emissions. the widespread implementation of such technologies will require a sustainable supply of biomass from forestry and agriculture. forests are a major source of feedstocks for biofuels production ...	2007	18478394
multipartite symbioses among fungi, mites, nematodes, and the spruce beetle, dendroctonus rufipennis.	the spruce beetle, dendroctonus rufipennis, is an eruptive forest pest of significant economic and ecological importance. d. rufipennis has symbiotic associations with a number of microorganisms, especially the ophiostomatoid fungus leptographium abietinum. the nature of this interaction is only partially understood. additionally, mite and nematode associates can mediate bark beetle-fungal interactions, but this has not yet been studied for spruce beetles. in this study, we found eight mite spec ...	2008	18801261
climate factors associated with historic spruce beetle (coleoptera: curculionidae) outbreaks in utah and colorado.	this study investigated relationships between climate and historic spruce beetle, dendroctonus rufipennis kirby (coleoptera: curculionidae), outbreaks in northern and southeastern utah and western colorado between 1905 and 1996. a chronology of outbreak years was constructed from historic records, research papers, newspapers, and other sources of information. historic climate data for the region included annual and mean monthly temperature and precipitation, in addition to palmer drought severit ...	2008	18419898
prepupal diapause and instar iv developmental rates of the spruce beetle, dendroctonus rufipennis (coleoptera: curculionidae, scolytinae).	the spruce beetle, dendroctonus rufipennis (kirby), is an important mortality agent of native spruces throughout north america. the life-cycle duration of this species varies from 1 to 3years depending temperature. the univoltine cycle (one generation per year) is thought to maximize outbreak risk and accelerate host mortality in established outbreaks. prepupal diapause is associated with the semivoltine cycle (one generation per 2years) and we investigated thermal conditions that result in diap ...	2011	21740908
presence and diversity of streptomyces in dendroctonus and sympatric bark beetle galleries across north america.	recent studies have revealed several examples of intimate associations between insects and actinobacteria, including the southern pine beetle dendroctonus frontalis and the spruce beetle dendroctonus rufipennis. here, we surveyed streptomyces actinobacteria co-occurring with 10 species of dendroctonus bark beetles across the united states, using both phylogenetic and community ecology approaches. from these 10 species, and 19 other scolytine beetles that occur in the same trees, we obtained 154 ...	2011	21249352
climate variability and spruce beetle (dendroctonus rufipennis) outbreaks in south-central and southwest alaska.	we used tree ring data (ad 1601-2007) to examine the occurrence of and climatic influences on spruce beetle (dendroctonus rufipennis) outbreaks in south-central and southwest alaska and found evidence of regional-scale outbreaks dating from the mid-1700s, related to climate variability at multiple temporal scales. over interannual time scales (approximately 1-3 years), el niño years, combined with severe late-summer drought, appeared to contribute significantly to spruce beetle outbreaks in the ...	2011	21870620
drought induces spruce beetle (dendroctonus rufipennis) outbreaks across northwestern colorado.	this study examines influences of climate variability on spruce beetle (dendroctonus rufipennis) outbreak across northwestern colorado during the period 1650 2011 ce. periods of broad-scale outbreak reconstructed using documentary records and tree rings were dated to 1843-1860, 1882-1889, 1931-1957, and 2004-2010. periods of outbreak were compared with seasonal temperature, precipitation, vapor pressure deficit (vpd), the palmer drought severity index (pdsi), and indices of ocean-atmosphere osci ...	2014	24933812
negative feedbacks on bark beetle outbreaks: widespread and severe spruce beetle infestation restricts subsequent infestation.	understanding disturbance interactions and their ecological consequences remains a major challenge for research on the response of forests to a changing climate. when, where, and how one disturbance may alter the severity, extent, or occurrence probability of a subsequent disturbance is encapsulated by the concept of linked disturbances. here, we evaluated 1) how climate and forest habitat variables, including disturbance history, interact to drive 2000s spruce beetle (dendroctonus rufipennis) i ...	2015	26000906
contrasting patterns of diterpene acid induction by red pine and white spruce to simulated bark beetle attack, and interspecific differences in sensitivity among fungal associates.	conifers possess a suite of physiochemical defenses that protect their subcortical tissues from bark beetle - fungal complexes. these defenses include rapid induction of terpenoids and phenolics at the site of attack. studies of the distribution, induction, and bioactivity of conifer terpenoids have focused heavily on monoterpenes. we assessed induction of diterpene acids in white spruce (picea glauca) and red pine (pinus resinosa) to fungal associates of two bark beetles, and the responses of f ...	2015	26003180
fire severity controlled susceptibility to a 1940s spruce beetle outbreak in colorado, usa.	the frequency, magnitude, and size of forest disturbances are increasing globally. much recent research has focused on how the occurrence of one disturbance may affect susceptibility to subsequent disturbances. while much has been learned about such linked disturbances, the strength of the interactions is likely to be contingent on the severity of disturbances as well as climatic conditions, both of which can affect disturbance intensity and tree resistance to disturbances. subalpine forests in ...	2016	27438289
lethal trap trees and semiochemical repellents as area host protection strategies for spruce beetle (coleoptera: curculionidae, scolytinae) in utah.	we tested lethal trap trees and repellent semiochemicals as area treatments to protect host trees from spruce beetle (dendroctonus rufipennis kirby) attacks. lethal trap tree treatments ("spray treatment") combined a spruce beetle bait with carbaryl treatment of the baited spruce. repellent treatments ("spray-repellent") combined a baited lethal trap tree within a 16-m grid of mch (3-methylcyclohex-2-en-1-one) and two novel spruce beetle repellents. after beetle flight, we surveyed all trees wit ...	2016	27515596
tree-ring isotopes reveal drought sensitivity in trees killed by spruce beetle outbreaks in south-central alaska.	increasing temperatures have resulted in reduced growth and increased tree mortality across large areas of western north american forests. we use tree-ring isotope chronologies (δ(13) c and δ(18) o) from live and dead trees from four locations in south-central alaska, usa, to test whether white spruce trees killed by recent spruce beetle (dendroctonus rufipennis kirby) outbreaks showed evidence of drought stress prior to death. trees that were killed were more sensitive to spring/summer temperat ...	2016	27755740
fire severity unaffected by spruce beetle outbreak in spruce-fir forests in southwestern colorado.	recent large and severe outbreaks of native bark beetles have raised concern among the general public and land managers about potential for amplified fire activity in western north america. to date, the majority of studies examining bark beetle outbreaks and subsequent fire severity in the u.s. rocky mountains have focused on outbreaks of mountain pine beetle (mpb; dendroctonus ponderosae) in lodgepole pine (pinus contorta) forests, but few studies, particularly field studies, have addressed the ...	2016	27411244
arthropod and oligochaete assemblages from grasslands of the southern kenai peninsula, alaska.	by the end of this century, the potential climate-biome of the southern kenai peninsula is forecasted to change from transitional boreal forest to prairie and grasslands, a scenario that may already be playing out in the caribou hills region. here, spruce (picea × lutzii little [glauca × sitchensis]) forests were heavily thinned by an outbreak of the spruce bark beetle (dendroctonus rufipennis (kirby, 1837)) and replaced by the native but invasive grass species, calamagrostis canadensis (michx.) ...	2017	28325976