Black Pine Bark Beetle | Hylastes ater (Paykull)

California Pest Rating for
Black Pine Bark Beetle | Hylastes ater (Paykull)
Pest Rating: A



Initiating Event:

Hylastes ater is currently Q-rated.  A permanent pest rating proposal is required to support an official pest rating.

History & Status:

Background: Hylastes ater is fairly large (3.5-4.4 mm long) sized for a bark beetle.  The beetle is dark in color, almost black.  Hylastes ater larval feeding appears to be limited to the roots and stumps of already-cut conifers (mostly pine, Pinus spp.).  Adults burrow into the phloem (inner bark), forming tunnels in which the larvae feed.  Feeding by newly-emerged adult bark beetles takes place in seedlings.  As is commonly the case with bark beetles, multiple species of fungi are associated with H. ater.  Sapstain fungi may be transferred to recently-cut logs by adult H. ater through their feeding.  This fungus can decrease the value of wood.

Worldwide Distribution: Hylastes ater is native to a large portion of the Palearctic, including much of Europe.  The species has been introduced to Australia, Chile, New Zealand, and South Africa.

Official Control: This species is considered a quarantine pest by Canada.

California Distribution:  This species is not known to be present in California.

California Interceptions: Hylastes ater has been intercepted in California on Pinus radiata wood from New Zealand (PDR # 1166010 and 1059432).

The risk Hylastes ater would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Hylastes ater is widely distributed in the Palearctic, and has demonstrated its ability to be introduced successfully to various localities, including Australia, Chile, and New Zealand. This species feeds on pines, which occur throughout California.  Therefore, Hylastes ater receives a High (3) in this category.

– Low (1) Not likely to establish in California; or likely to establish in very limited areas.

– Medium (2) may be able to establish in a larger but limited part of California.

High (3) likely to establish a widespread distribution in California.

2) Known Pest Host Range: Hylastes ater has been reported to feed on many species of pines as well as other coniferous trees. Therefore, it receives a Medium (2) in this category.

– Low (1) has a very limited host range.

Medium (2) has a moderate host range.

– High (3) has a wide host range.

3) Pest Dispersal Potential: Hylastes ater flies, and has successfully been introduced to several countries. Adults are strongly attracted to freshly-cut logs, which means these beetles are likely to be present on logs/firewood that are not removed immediately after cutting.  This would enable the beetles to be moved with the logs/firewood.  Therefore, it receives a Medium (2) in this category.

– Low (1) does not have high reproductive or dispersal potential.

Medium (2) has either high reproductive or dispersal potential.

– High (3) has both high reproduction and dispersal potential.

4) Economic Impact: Hylastes ater has been reported to cause heavy mortality of pine seedlings in New Zealand, primarily as a result of the feeding of newly emerged adults described above.  There is some evidence that healthy seedlings are generally not damaged or killed as a result of this feeding, and that it is only otherwise-compromised seedlings that are affected.  Assuming that healthy seedlings are damaged or killed, the introduction of ater to California could impact the timber industry through increasing production costs, both through loss of seedlings as well as infection of logs by sapstain fungi.  Timing of cutting or harvesting of timber could require modification, to avoid the beetles.  Therefore, it receives a High (3) in this category.

Economic Impact:  B, D, E

A. The pest could lower crop yield.

B. The pest could lower crop value (includes increasing crop production costs).

C. The pest could trigger the loss of markets (includes quarantines).

D. The pest could negatively change normal cultural practices.

E. The pest can vector, or is vectored, by another pestiferous organism.

F. The organism is injurious or poisonous to agriculturally important animals.

G. The organism can interfere with the delivery or supply of water for agricultural uses.

Economic Impact Score: 3

– Low (1) causes 0 or 1 of these impacts.

– Medium (2) causes 2 of these impacts.

High (3) causes 3 or more of these impacts.

5) Environmental Impact: There does not appear to be any evidence that Hylastes ater has a significant environmental impact in any of the areas to which it has been introduced. Any significant damage to pine seedlings in timber operations may be related to the artificially higher density of food sources (wood waste) and resulting high densities of adult beetles.  However, it is possible that this species could have a different impact in California if it was introduced here.  There is also a possibility that the species could carry a fungal pathogen to which California trees are susceptible.  Forest ecosystems and rare California conifers could be affected.  Therefore, it receives a High (3) in this category.

Evaluate the environmental impact of the pest on California using the criteria below.

Environmental Impact:  A,B

A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.

B. The pest could directly affect threatened or endangered species.

C. The pest could impact threatened or endangered species by disrupting critical habitats.

D. The pest could trigger additional official or private treatment programs.

E. The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.

Score the pest for Environmental Impact. Score:

Environmental Impact Score: 

– Low (1) causes none of the above to occur.

– Medium (2) causes one of the above to occur.

High (3) causes two or more of the above to occur.

Consequences of Introduction to California for Hylastes ater: High (13)

Add up the total score and include it here.

–Low = 5-8 points

–Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Hylastes ater is not known to be present in California.  It receives a Not established (0) in this category.

Not established (0) Pest never detected in California, or known only from incursions.

–Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).

–Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.

–High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.

Final Score:

The final score is the consequences of introduction score minus the post entry distribution and survey information score: High (13)


Besides any damage to already-cut timber by the transmitted fungi, the only evidence so far of damage resulting from this beetle is the feeding by newly emerged adults on tree seedlings.  There appears to be some uncertainty regarding the ability of the adults to injure or kill healthy pine seedlings; some research suggests that injured/killed seedlings were originally in poor health prior to being fed upon.

Conclusion and Rating Justification:

Hylastes ater is a bark beetle that is not known to occur in the United States and has the potential to impact the timber industry through direct feeding damage of seedlings or transmission of pathogenic fungi.  There could be environmental impacts as well.  In addition, there are pine species in California (some of them rare) that this bark beetle has not encountered before, and the behavior (including damage) of the beetle could be different from what has been observed to date in other parts of the world.  An “A” rating is justified.


Bain, J., Berndt, L., and B. Gresham.  2009.  Forest and timber insects in New Zealand.  Number 29: Black pine bark beetle.

CABI.  2017.  Invasive Species Compendium. Wallingford, UK: CAB International.

EPPO.  2017.  EPPO Global Database (available online).  Accessed 21 September 2017.

Kliejunas, J.T, Burdsall Jr., H.H., DeNitto, G.A., Eglitis, A., Haugen, D.A., Haverty, M.I., and J.A. Micales.  2006.  Pest risk assessment of the importation into the United States of unprocessed Pinus logs and chips from Australia.  United States Department of Agriculture.  159 pp.

Reay, S.D., Glare, T.R., and M. Brownbridge.  2012.  Hylastes ater (Curculionidae: Scolytinae) affecting Pinus radiata seedling establishment in New Zealand.  Psyche.  2012: 1-9.

Wood, S.L.  1982.  The bark and ambrosia beetles of North and Central America (Coleoptera: Scolytidae), a taxonomic monograph.  Brigham Young University.  1359 pp.

Wood, S.L.  2007.  Bark and ambrosia beetles of South America.  Brigham Young University.  900 pp.


Kyle Beucke, 1220 N Street, Room 221, Sacramento, CA, 95814, 916-403-6741,[@]

Responsible Party:

Jason Leathers, 2800 Gateway Oaks Drive, Sacramento CA 95833, (916) 654-1211;[@]

Comment Period:* CLOSED

1/17/2018 – 3/3/2018


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Pest Rating: A

Posted by ls