A tree trunk with beetle engravings

Many different species of bark and wood boring beetles currently threaten California forests. Some native, some not, bark beetles have become particularly widespread following many years of drought. These pests cause disease and die-off in healthy trees and are the cause of widespread mortality in many swathes of the California forest landscape. 

 General Resources on Bark, Wood Boring & Ambrosia Beetles

Bark & Wood Boring Beetles

Ambrosia Beetle

Monarthrum sp.

More information coming soon

Ambrosia beetle, E. Richard Hoebeke, Cornell University, Bugwood.org
Ambrosia beetle, E. Richard Hoebeke, Cornell University, Bugwood.org

Ambrosia beetle

Ambrosia beetle, E. Richard Hoebeke, Cornell University, Bugwood.org
Ambrosia beetle, E. Richard Hoebeke, Cornell University, Bugwood.org

Ambrosia beetle

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Asian Long-Horned Beetle

Anoplophora glabripennis

The Asian Longhorned Beetle (Anoplophora glabripennis, or ALB) is a threat to America’s hardwood trees.

Location: California, Massachusetts, New York, Ohio

Impact Significance:

Destructive wood-boring pest of maple and other hardwoods. It threatens recreation and forest resources valued at billions of dollars.

Hosts: Hardwood Trees

Biology:

Wood-boring invasive insect. Adult beetles are large, distinctive-looking insects measuring 1 to 1.5 inches in length with long antennae. Their bodies are black with small white spots, and their antennae are banded in black and white.

Damage:

Females lay eggs under the bark of the tree. In two weeks, larva bores into the tree, feeding on the living tissue. Over the course of a year, larvae turn into adults. Adults then chew their way out of the tree, leaving exit holes. Finally, the adults feed on leaves and bark. This process eventually kills the tree.

Asian long-horned beetle, Gerald J. Lenhard, Louisiana State University, Bugwood.org
Asian long-horned beetle, Gerald J. Lenhard, Louisiana State University, Bugwood.org

Asian long-horned beetle

Asian long-horned beetle, Kenneth R. Law, USDA APHIS PPQ, Bugwood.org
Asian long-horned beetle, Kenneth R. Law, USDA APHIS PPQ, Bugwood.org

Asian long-horned beetle

Asian long-horned beetle, Gerald J. Lenhard, Louisiana State University, Bugwood.org
Asian long-horned beetle, Gerald J. Lenhard, Louisiana State University, Bugwood.org

Asian long-horned beetle

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Learn More

California Five-Spined Ips

More information coming soon

California five-spined ips, Pest and Diseases Image Library , Bugwood.org
California five-spined ips, Pest and Diseases Image Library , Bugwood.org

California five-spined ips

California five-spined ips, Damage, Christine Buhl, Oregon Department of Forestry, Bugwood.org
California five-spined ips, Damage, Christine Buhl, Oregon Department of Forestry, Bugwood.org

California five-spined ips

California five-spined ips, Pest and Diseases Image Library , Bugwood.org
California five-spined ips, Pest and Diseases Image Library , Bugwood.org

California five-spined ips

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Ips paraconfusus

Cedar Bark Beetle

Pholeosinus spp.

More information coming soon

Cedar bark beetle, E. Richard Hoebeke, Cornell University, Bugwood.org
Cedar bark beetle, E. Richard Hoebeke, Cornell University, Bugwood.org

Cedar bark beetle

Cedar bark beetle damage, William M. Ciesla, Forest Health Management International, Bugwood.org
Cedar bark beetle damage, William M. Ciesla, Forest Health Management International, Bugwood.org

Cedar bark beetle damage

Cedar bark beetle, E. Richard Hoebeke, Cornell University, Bugwood.org
Cedar bark beetle, E. Richard Hoebeke, Cornell University, Bugwood.org

Cedar bark beetle

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Douglas Fir Engraver

More information coming soon

Douglas fir engraver, Joseph Benzel, Screening Aids, USDA APHIS PPQ, Bugwood.org
Douglas fir engraver, Joseph Benzel, Screening Aids, USDA APHIS PPQ, Bugwood.org

Douglas fir engraver

Douglas fir engraver damage, Wayne Brewer, Auburn University, Bugwood.org
Douglas fir engraver damage, Wayne Brewer, Auburn University, Bugwood.org

Douglas fir engraver damage

Douglas fir engraver, Joseph Benzel, Screening Aids, USDA APHIS PPQ, Bugwood.org
Douglas fir engraver, Joseph Benzel, Screening Aids, USDA APHIS PPQ, Bugwood.org

Douglas fir engraver

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Scolytus unispinosus

Douglas Fir Beetle

Dendroctonus pseudotsugae

More information coming soon

douglas fir beetle, William M. Ciesla, Forest Health Management International, Bugwood.org
douglas fir beetle, William M. Ciesla, Forest Health Management International, Bugwood.org

douglas fir beetle

Douglas fir beetle engravings, William M. Ciesla, Forest Health Management International, Bugwood.or
Douglas fir beetle engravings, William M. Ciesla, Forest Health Management International, Bugwood.or

Douglas fir beetle engravings

douglas fir beetle, William M. Ciesla, Forest Health Management International, Bugwood.org
douglas fir beetle, William M. Ciesla, Forest Health Management International, Bugwood.org

douglas fir beetle

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Emerald Ash Borer

Emerald ash borer (EAB) is an invasive insect from Asia that kills ash trees.

Location: California, Various

Impact Significance: Trees lose 30 to 50% of canopy after 2 years infestation and die within 3-4 years

Hosts: White ash (Fraxinus americana), black ash (F.nigra), red ash (F. pennslyvanica), green ash (F. pennsylvanica var. subintegerrima) and several horticultural varieties of ash

Biology: The body is a golden green or brassy color overall with darker, metallic emerald green wing covers.

Damage:

Killed hundreds of millions of ash trees in North America. The adult beetles nibble on ash foliage but cause little damage. The larvae (the immature stage) feed on the inner bark of ash trees, disrupting the tree’s ability to transport water and nutrients.

Emerald Ash Borer
Emerald Ash Borer

Emerald Ash Borer

Emerald Ash Borer
Emerald Ash Borer

Emerald Ash Borer

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Agrilus planipennis

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Fir Engraver

More information coming soon

Fir engraver, Donald Owen, California Department of Forestry and Fire Protection, Bugwood.org
Fir engraver, Donald Owen, California Department of Forestry and Fire Protection, Bugwood.org

Fir engraver

Fir engraver damage, Donald Owen, California Department of Forestry and Fire Protection, Bugwood.org
Fir engraver damage, Donald Owen, California Department of Forestry and Fire Protection, Bugwood.org

Fir engraver damage

Fir engraver, Donald Owen, California Department of Forestry and Fire Protection, Bugwood.org
Fir engraver, Donald Owen, California Department of Forestry and Fire Protection, Bugwood.org

Fir engraver

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Scolytus ventralis

Goldspotted Oak Borer

Agrilus coxalis

The goldspotted oak borer is an invasive beetle killing mature susceptible oak trees in southern California. It continues to spread to new locations.

Location: San Diego, Riverside and Orange Counties in southern California

Impact Significance: Widespread oak mortality can have severe implications to the environment and human safety.

Hosts: GSOB attacks only oaks and prefers those in the red oak group including coast live oak, California black oak, canyon live oak, and Engelmann oak (rare).

Biology:

The goldspotted oak borer (GSOB), Agrilus auroguttatus (Coleoptera: Buprestidae), is a flatheaded borer new to California that poses a significant threat to oak trees.

Damage:

GSOB larvae feed beneath the bark of certain oaks near the interface of the phloem and xylem, the nutrient and water conducting tissues of plants. The larvae damage both of these tissues as well as the cambium, a unicellular layer between the phloem and xylem that is responsible for the radial growth of the tree. Trees die after several years of injury inflicted by multiple generations of the beetle, causing significant economic, ecological, cultural, and aesthetic losses to the region. As of 2010, GSOB has killed an estimated 21,500 trees covering 1,893 square miles in San Diego County in forests, parks, and residential landscapes.

Gold Spotted Oak Borer
Gold Spotted Oak Borer

Gold Spotted Oak Borer

Gold Spotted Oak Borer
Gold Spotted Oak Borer

Gold Spotted Oak Borer

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Invasive Shot Hole Borers

Euwallacea sp.

Invasive shot hole borers are invasive beetles in southern California that carry invasive fungi with them into the trees they attack. The beetle/disease complex can attack hundreds of tree species and can kill those species that are reproductive hosts for the beetles. The beetle/disease complex continues to spread to new locations.

Location: Southern California

Impact Significance: Distribution of PSHB/FD and KSHB/FD in California

Hosts:

The Polyphagous Shot Hole Borer (PSHB) attacks dozens of tree species, including commercial avocado groves, common landscape trees, and native species in urban and wildland environments. A closely related beetle called the Kuroshio Shot Hole Borer (KSHB) has been detected in San Diego County. KSHB looks identical to PSHB and also carries disease-causing fungi, but the species are genetically distinct.

Biology:

Polyphagous Shot Hole Borer (PSHB), Euwallacea sp. is an invasive beetle that attacks dozens of common native and landscape trees. The tiny beetle tunnels into host trees and spreads Fusarium Dieback (FD), a disease know to infect over 110 tree species. FD is caused by Fusarium euwallaceae, a fungus that disrupts the transport of water and nutrients in the tree, leading to branch dieback and overall decline.

Damage:

PSHB spreads a disease called Fusarium Dieback (FD), which is caused by pathogenic fungi. Trees that are FD-susceptible may experience branch dieback, canopy loss, and, in some cases, tree mortality.

Invasive shot hole borer
Invasive shot hole borer

Invasive shot hole borer

Invasive shot hole borer
Invasive shot hole borer

Invasive shot hole borer

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Ips Beetle

Ips spp.

The native Ips beetle attacks pines at the top of the tree in small branches of suppressed, diseased or injured trees.

Ips. Timothy Haley, USDA Forest Service, Bugwood.org
Ips. Timothy Haley, USDA Forest Service, Bugwood.org

Ips calligraphus and Ips grandicollis galleries in windthrown longleaf

Ips Beetle
Ips Beetle

Ips Beetle

Ips. Timothy Haley, USDA Forest Service, Bugwood.org
Ips. Timothy Haley, USDA Forest Service, Bugwood.org

Ips calligraphus and Ips grandicollis galleries in windthrown longleaf

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Jeffrey Pine Beetle

Dendroctonus jefferyi

Status: Native

Hosts (in California): Jeffrey pine

Management: The bole spray insecticide carbaryl is typically effective in protecting trees from Jeffrey pine beetle. Semiochemical-based anti-aggregation products, like those used to protect other pine species from bark beetles, haven’t been developed for Jeffrey pine beetle, in part because an aggregation pheromone (needed for testing such a product) hasn’t been fully developed. As with most bark beetles, maintaining healthy, well-spaced, vigorous stands increases tree defense (resin flow). Diversity in tree species present in stands is also typically beneficial since western pine beetle won’t attack, colonize, or reproduce in non-hosts. A forest health professional should be consulted for site and time specific control measures.

Highlights: Jeffrey pine beetle looks very similar to mountain pine beetle. Its galleries are similar, although not identical. Jeffrey pine beetle is one of the largest species of bark beetles. Like many bark beetles, Jeffrey pine beetle carries yeasts along with a mycangial blue-staining fungus—in this case Ophiostoma claviger—with it.

Jeffrey pine beetle. Erich G. Vallery, USDA Forest Service - SRS-4552, Bugwood.org
Jeffrey pine beetle. Erich G. Vallery, USDA Forest Service - SRS-4552, Bugwood.org

Jeffrey pine beetle

Blue stain fungus on a Jeffrey pine colonized by Jeffrey pine beetle. USDA Forest Service - Forest H
Blue stain fungus on a Jeffrey pine colonized by Jeffrey pine beetle. USDA Forest Service - Forest H

Blue stain fungus on a Jeffrey pine colonized by Jeffrey pine beetle

Jeffery pine beetle damage, tia smith, Bugwood.org
Jeffery pine beetle damage, tia smith, Bugwood.org

Jeffery pine beetle damage

Jeffrey pine beetle. Erich G. Vallery, USDA Forest Service - SRS-4552, Bugwood.org
Jeffrey pine beetle. Erich G. Vallery, USDA Forest Service - SRS-4552, Bugwood.org

Jeffrey pine beetle

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Recommended Literature

Bradley, T. and Tueller, P., 2001. Effects of fire on bark beetle presence on Jeffrey pine in the Lake Tahoe Basin. Forest Ecology and Management, 142(1-3), pp.205-214.

Egan, J.M., Sloughter, J.M., Cardoso, T., Trainor, P., Wu, K., Safford, H. and Fournier, D., 2016. Multi-temporal ecological analysis of Jeffrey pine beetle outbreak dynamics within the Lake Tahoe Basin. Population ecology, 58(3), pp.441-462.

Hood, S.M., Cluck, D.R., Jones, B.E. and Pinnell, S., 2018. Radial and stand‐level thinning treatments: 15‐year growth response of legacy ponderosa and Jeffrey pine trees. Restoration Ecology, 26(5), pp.813-819.

Paine, T.D., Millar, J.G., Hanlon, C.C. and Hwang, J.S., 1999. Identification of semiochemicals associated with Jeffrey pine beetle, Dendroctonus jeffreyi. Journal of chemical ecology, 25(3), pp.433-453.

Seybold, S.J., Bentz, B.J., Fettig, C.J., Lundquist, J.E., Progar, R.A. and Gillette, N.E., 2018. Management of western North American bark beetles with semiochemicals. Annual review of entomology, 63, pp.407-432.

Smirnova, E., Khormali, O. and Egan, J.M., 2019. Functional analysis of spatial aggregation regions of Jeffrey pine beetle-attack within the Lake Tahoe Basin. Statistics & Probability Letters, 144, pp.57-62.

Mediterranean Oak Borer

Xyleborus monographus

More information coming soon

Mediterranean oak borer Maja Jurc, University of Ljubljana, Bugwood.org
Mediterranean oak borer Maja Jurc, University of Ljubljana, Bugwood.org

Mediterranean oak borer

Mediterranean oak borer Maja Jurc, University of Ljubljana, Bugwood.org
Mediterranean oak borer Maja Jurc, University of Ljubljana, Bugwood.org

Mediterranean oak borer

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Mountain Pine Beetle

Dendroctonus ponderosae

Status: Native

Hosts (in California): All pines, very rare in Jeffrey pine

Management: Products utilizing synthetically produced verbenone, an anti-aggregation pheromone produced by mountain pine beetle, can often be effective in protecting individual or small numbers of trees from mountain pine beetle attack and colonization. Additionally, the bole spray insecticide carbaryl is typically effective in protecting trees from mountain pine beetle. As with most bark beetles, maintaining healthy, well-spaced, vigorous stands increases tree defense (resin flow). Non-pine species present in stands is also beneficial since mountain pine beetle are highly unlikely to attack, colonize, or reproduce in non-pines. A forest health professional should be consulted for site and time specific control measures.

 

Highlights: Mountain pine beetle is the most impactful forest insect in western North America. It has impacted greater than 27 million hectares since 2000. The projected losses from mountain pine beetle is ~65.8 million m2 of basal area between 2013 and 2027. Since 2000, mountain pine beetle has been responsible for roughly half of the area impacted by bark beetles in the western U.S. As such, mountain pine beetle is the most researched and targeted (by management activities) species in western North America. Mountain pine beetle’s primary host is lodgepole pine (Pinus contorta), however, unlike many bark beetles, it also will attack and colonize a wide variety of pine species. Mountain pine beetle has “J”-shaped galleries. Mountain pine beetle typically initiates attack in the lower 15 feet of the tree bole, although crowns can be attacked upon occasion.

Mountain pine beetle. Javier E. Mercado, USDA Forest Service, Bugwood.org
Mountain pine beetle. Javier E. Mercado, USDA Forest Service, Bugwood.org

Mountain pine beetle

Mountain pine beetle galleries. Ronald F. Billings, Texas A&M Forest Service, Bugwood.org
Mountain pine beetle galleries. Ronald F. Billings, Texas A&M Forest Service, Bugwood.org

Mountain pine beetle engravings

Bark beetle damage, USDA Forest Service - Region 2 - Rocky Mountain Region , USDA Forest Service, Bu
Bark beetle damage, USDA Forest Service - Region 2 - Rocky Mountain Region , USDA Forest Service, Bu

Bark beetle damage

Mountain pine beetle. Javier E. Mercado, USDA Forest Service, Bugwood.org
Mountain pine beetle. Javier E. Mercado, USDA Forest Service, Bugwood.org

Mountain pine beetle

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Recommended Literature

Audley, J.P., Fettig, C.J., Munson, A.S., Runyon, J.B., Mortenson, L.A., Steed, B.E., Gibson, K.E., Jørgensen, C.L., McKelvey, S.R., McMillin, J.D. and Negrón, J.F., 2020. Impacts of mountain pine beetle outbreaks on lodgepole pine forests in the Intermountain West, US, 2004–2019. Forest Ecology and Management, 475, p.118403.

Dudney, J.C., Nesmith, J.C., Cahill, M.C., Cribbs, J.E., Duriscoe, D.M., Das, A.J., Stephenson, N.L. and Battles, J.J., 2020. Compounding effects of white pine blister rust, mountain pine beetle, and fire threaten four white pine species. Ecosphere, 11(10), p.e03263.

Fettig, C.J., Gibson, K.E., Munson, A.S. and Negrón, J.F., 2014. Cultural practices for prevention and mitigation of mountain pine beetle infestations. Forest Science, 60(3), pp.450-463.

Fettig, C. J., Mortenson, L. A., Bulaon, B. M. & Foulk, P. B. Tree mortality following drought in the central and southern Sierra Nevada, California, U.S. Forest Ecology and Management 432, 164–178 (2019).

Fettig, C.J., Steed, B.E., Bulaon, B.M., Mortenson, L.A., Progar, R.A., Bradley, C.A., Munson, A.S. and Mafra-Neto, A. 2017. Efficacy of SPLAT® Verb for Protecting Individual Pinus contorta, Pinus ponderosa, and Pinus lambertiana from mortality attributed to Dendroctonus ponderosae. Journal of the Entomological Society of British Columbia, 11-20.

Gibson, K., and S. Kegley. 2004. Testing the efficacy of verbenone in reducing mountain pine beetle attacks in second-growth ponderosa pine. FHP Report 04–7. U.S. Department of Agriculture, Forest Service, Missoula, MT.

Preisler, H.K. and R.G. Mitchell. 1993. Colonization patterns of the mountain pine beetle in thinned and unthinned lodgepole pine stands. Forest Science 89(3):528-545.

Seybold, S.J., Bentz, B.J., Fettig, C.J., Lundquist, J.E., Progar, R.A. and Gillette, N.E., 2018. Management of western North American bark beetles with semiochemicals. Annual review of entomology, 63, pp.407-432.

Pine Engraver

Ips pini

More information coming soon

Pine engraver, Ron Long, Simon Fraser University, Bugwood.org
Pine engraver, Ron Long, Simon Fraser University, Bugwood.org

Pine engraver

Pine engraver damage, Texas A&M Forest Service , Bugwood.org
Pine engraver damage, Texas A&M Forest Service , Bugwood.org

Pine engraver damage

Pine engraver, Ron Long, Simon Fraser University, Bugwood.org
Pine engraver, Ron Long, Simon Fraser University, Bugwood.org

Pine engraver

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Polyphagous Shot Hole Borer

More information coming soon

Polyphagous shot hole borer, Javier E. Mercado, Bark Beetle Genera of the U.S., USDA APHIS PPQ, Bugw
Polyphagous shot hole borer, Javier E. Mercado, Bark Beetle Genera of the U.S., USDA APHIS PPQ, Bugw

Polyphagous shot hole borer

Polyphagous shot hole borer, Javier E. Mercado, Bark Beetle Genera of the U.S., USDA APHIS PPQ, Bugw
Polyphagous shot hole borer, Javier E. Mercado, Bark Beetle Genera of the U.S., USDA APHIS PPQ, Bugw

Polyphagous shot hole borer

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Euwallacea sp.

Red Turpentine Beetle

Dendroctonus valens

Status: Native

Hosts (in California): All pines including introduced species. Occasionally attacks other conifers.

Management: Typically, red turpentine beetle attacks are an indication of deteriorating tree health, from wounding, disease, fire damage, or attack by another bark beetle species. As such, attending to these other issues as best as possible is usually recommended rather than managing for red turpentine beetle specifically. Chipped or cut pine pieces can also often lead to attacks on adjacent live trees. In general, larger, healthy trees will survive attack from red turpentine beetle, while smaller—and in particular drought stressed—trees may experience mortality. Though uncommon, occasionally red turpentine beetle will attack, colonize, and kill large seemingly healthy trees, especially during periods of drought. The bole spray insecticide carbaryl and pyrethroids such as permethrin or bifenthrin are typically effective in preventing attacks from red turpentine beetle. Semiochemical-based anti-aggregation products, like those used to protect other pine species from bark beetles, haven’t been developed specifically for red turpentine beetle. As with most bark beetles, maintaining healthy, well-spaced, vigorous stands increases tree defense (resin flow). Diversity in tree species present in stands is also typically beneficial since western pine beetle seldom attacks non-hosts. A forest health professional should be consulted for site and time specific control measures.

Highlights: Red turpentine beetle is the largest bark beetle in North America and is a visually pleasing red-brown color. Males often make an audible chirp when handled. Red turpentine attacks the lower bole and galleries can extend below the root collar. Red turpentine beetle is typically viewed as an opportunist, yet it’s contribution to tree decline and mortality is poorly understood. However, in China, where red turpentine beetle has been introduced, it has caused substantial mortality of native pines, particularly Chinese red pine, (Pinus tabuliformis). It is thought the more lethal nature of red turpentine beetle in China may be in part due to fungal associates isolated from it in China that haven’t been found in North America. As such, there is concern about red turpentine beetle from China—with non-North American fungal associates—coming back to North America and being considerably more lethal than red turpentine beetle currently found in North America.

Red turpentine beetle. Steven Valley, Oregon Department of Agriculture, Bugwood.org
Red turpentine beetle. Steven Valley, Oregon Department of Agriculture, Bugwood.org

Red turpentine beetle

Resinous granular boring “dust” at the base of burnt tree. Donald Owen, California Department of For
Resinous granular boring “dust” at the base of burnt tree. Donald Owen, California Department of For

Resinous granular boring “dust” at the base of burnt tree

Red turpentine beetle, USDA Forest Service - Northeastern Area , USDA Forest Service, Bugwood.org
Red turpentine beetle, USDA Forest Service - Northeastern Area , USDA Forest Service, Bugwood.org

Red turpentine beetle damage

Red turpentine beetle. Steven Valley, Oregon Department of Agriculture, Bugwood.org
Red turpentine beetle. Steven Valley, Oregon Department of Agriculture, Bugwood.org

Red turpentine beetle

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Recommended Literature

Fettig, C.J., McMillin, J.D., Anhold, J.A., Hamud, S.M., Borys, R.R., Dabney, C.P. and Seybold, S.J., 2006. The effects of mechanical fuel reduction treatments on the activity of bark beetles (Coleoptera: Scolytidae) infesting ponderosa pine. Forest Ecology and Management, 230(1-3), pp.55-68.

Kelsey, R.G. and Westlind, D.J., 2020. Red turpentine beetle primary attraction to (–)-β-pinene+ ethanol in US Pacific Northwest ponderosa pine forests. PloS one, 15(7), p.e0236276.

Owen, D.R., Wood, D.L. and Parmeter Jr, J.R., 2005. Association between Dendroctonus valens and black stain root disease on ponderosa pine in the Sierra Nevada of California. Canadian entomologist, 137(3), p.367.

Seybold, S.J., Bentz, B.J., Fettig, C.J., Lundquist, J.E., Progar, R.A. and Gillette, N.E., 2018. Management of western North American bark beetles with semiochemicals. Annual review of entomology, 63, pp.407-432.

Westlind, D.J. and Kelsey, R.G., 2019. Predicting post-fire attack of red turpentine or western pine beetle on ponderosa pine and its impact on mortality probability in Pacific Northwest forests. Forest Ecology and Management, 434, pp.181-192.

Westlind, D.J. and Kerns, B.K., 2021. Repeated fall prescribed fire in previously thinned Pinus ponderosa increases growth and resistance to other disturbances. Forest Ecology and Management, 480, p.118645.

Yan, Z., Sun, J., Don, O. and Zhang, Z., 2005. The red turpentine beetle, Dendroctonus valens LeConte (Scolytidae): an exotic invasive pest of pine in China. Biodiversity & Conservation, 14(7), pp.1735-1760.

Western Oak Bark Beetle

Pseudopityophthorus pubipennis

More information coming soon

Western Pine Beetle

Dendroctonus brevicomis

Status: Native

Hosts (in California): Ponderosa pine, Coulter pine

Management:

The bole spray insecticide carbaryl is typically effective in protecting trees from western pine beetle. Western pine beetle does often exhibit a response to verbenone, an antiaggregant of mountain pine beetle which has been successfully used in semiochemical-based products to protect pine species from mountain pine beetle. However, verbenone alone hasn’t been effective in protecting trees from western pine beetle at levels deemed satisfactory. Research and development are ongoing on this topic. As with most bark beetles, maintaining healthy, well-spaced, vigorous stands increases tree defense (resin flow). Diversity in tree species present in stands is also typically beneficial since western pine beetle won’t attack, colonize, or reproduce in non-hosts. A forest health professional should be consulted for site and time specific control measures.

Highlights:

Western pine beetle was the most prominent mortality-causing bark beetle in the 2014-16 drought-driven, severe tree mortality event in the central and southern Sierra Nevada. Western pine beetle has very distinct sinuous, crisscrossing galleries. Ponderosa pine trees with significant outer bark removed by woodpeckers typically offers evidence of western pine beetle colonization, as unlike other bark beetle species, western pine beetle complete their development in the outer bark.

Western pine beetle. Erich G. Vallery, USDA Forest Service – SRS-4552, Bugwood.org
Western pine beetle. Erich G. Vallery, USDA Forest Service – SRS-4552, Bugwood.org

A western pine beetle up close

Western pine beetle.
Western pine beetle.

Western pine beetle.

Western Pine Beetle Damage. Mark McGregor, USDA Forest Service, Bugwood.org
Western Pine Beetle Damage. Mark McGregor, USDA Forest Service, Bugwood.org

Western Pine Beetle Damage. Mark McGregor, USDA Forest Service, Bugwood.org

Western pine beetle. Erich G. Vallery, USDA Forest Service – SRS-4552, Bugwood.org
Western pine beetle. Erich G. Vallery, USDA Forest Service – SRS-4552, Bugwood.org

A western pine beetle up close

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Learn More

Recommended Literature

Fettig, C.J., 2019. Socioecological impacts of the western pine beetle outbreak in southern California: lessons for the future. Journal of Forestry, 117(2), pp.138-143.

Fettig, C.J. and McKelvey, S.R., 2014. Resiliency of an interior ponderosa pine forest to bark beetle infestations following fuel-reduction and forest-restoration treatments. Forests, 5(1), pp.153-176.

Fettig, C. J., Mortenson, L. A., Bulaon, B. M. & Foulk, P. B. Tree mortality following drought in the central and southern Sierra Nevada, California, U.S. Forest Ecology and Management 432, 164–178 (2019).

Koontz, M.J., Latimer, A.M., Mortenson, L.A., Fettig, C.J. and North, M.P., 2021. Cross-scale interaction of host tree size and climatic water deficit governs bark beetle-induced tree mortality. Nature communications, 12(1), pp.1-13.

Miller, J. M. and F. P. Keen. 1960. Biology and control of the western pine beetle. U.S. Department of Agriculture Misc. Publ. 800, Washington, DC. 381 p.

Restaino, C., Young, D.J., Estes, B., Gross, S., Wuenschel, A., Meyer, M. and Safford, H., 2019. Forest structure and climate mediate drought‐induced tree mortality in forests of the Sierra Nevada, USA. Ecological Applications, 29(4), p.e01902.

Seybold, S.J., Bentz, B.J., Fettig, C.J., Lundquist, J.E., Progar, R.A. and Gillette, N.E., 2018. Management of western North American bark beetles with semiochemicals. Annual review of entomology, 63, pp.407-432.

Stark, D.T., Wood, D.L., Storer, A.J. and Stephens, S.L., 2013. Prescribed fire and mechanical thinning effects on bark beetle caused tree mortality in a mid-elevation Sierran mixed-conifer forest. Forest Ecology and Management, 306, pp.61-67.

Wood Boring Beetle

Dendroctonus brevicomis

Three groups of wood-boring beetles powderpost, deathwatch, and false powderpost invade and damage wood furniture as well as structural and decorative wood inside of buildings.

Location: California

Impact Significance:  Wood-boring beetles invade and damage wood furniture as well as structural and decorative wood inside of buildings. Adults of some species also bore exit holes through plaster, plastic, and even soft metals that might cover the underlying wood.

Hosts: Adult powderpost beetles most often select and lay eggs in wood such as oak, ash, hickory, mahogany, and walnut, and infestations are most likely to occur in wood paneling, molding, flooring, window and door frames, plywood, bamboo articles, and furniture. Deathwatch beetles primarily infest softwoods, especially Douglas-fir, which is used in girders, beams, foundation timbers, and some types of furniture. False powderpost beetles colonize a variety of hardwoods and sometimes softwoods

Biology: Wood-boring beetles in the Anobiidae, Bostrichidae beetle families.

Damage: Structural damage to wood structures.

Wood Boring Beetle
Wood Boring Beetle

Wood Boring Beetle

Wood Boring Beetle. Joseph Berger, Bugwood.org
Wood Boring Beetle. Joseph Berger, Bugwood.org

Wood boring beetle

Wood Boring Beetle
Wood Boring Beetle

Wood Boring Beetle

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