Beetle | Semanotus sinoauster Gressitt

California Pest Rating for
Beetle | Semanotus sinoauster Gressitt
Coleoptera: Cerambycidae
Pest Rating: A




Initiating Event:

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

History & Status:

Background:  Semanotus sinoauster is a beetle that measure 1.3 to 2 cm in length and is black to reddish-brown with black and yellow bands on the elytra (Niisato, 2004).  The larvae feed in the wood of Chinese fir (Cunninghamia lanceolata) (Cupressaceae).  This beetle is reported to be a pest of this tree, which suggests that living trees are attacked, but definite information has not been found regarding the condition of the trees attacked (e.g., healthy, dead, or compromised).  This beetle may also attack Fokienia hodginsii (Cupressaceae) (Niisato, 2004).  Other Semanotus species are reported to attack living trees as well as recently-killed trees, for example, those brought down by wind.  For example, Semanotus laurasii was introduced to Europe from Africa and it is reported to attack, injure, and kill cypress trees in Spain, and Semanotus japonicus is reported to attack live Japanese cedar and cypress trees (Martínez-Blay et al., 2014; Togashi, 1985).  Experiments with S. japonicus larvae demonstrated that larvae can only develop in fresh wood, likely because of the higher nutritional content, but they can be killed with resin flow by healthy trees.  This suggests that Semanotus species in general (including S. sinoauster) could take advantage of living trees that are weakened or otherwise unable to mount a successful defense of resin flow (Shibata, 1995).

Even if S. sinoauster only attacks dead or dying trees, it could still cause losses to timber.  Other Semanotus species are reported to cause such damage.  For example, S. litogiosus was reported to be the most important source of borer-induced timber deterioration in wind-thrown firs in California (Wickman, 1965).

Other Semanotus species are reported not to require maturation feeding (pre-reproductive feeding by adults, typically on living tissues of trees), and S. sinoauster is presumed to be similar (Blay, 2014; Cherepanov, 1988).

Semanotus bifasciatus sinoauster Gressitt is a synonym of S. sinoauster.  Information reported for this synonym was considered in this proposal.

Worldwide Distribution:  Semanotus sinoauster is reported from and presumably native to southern China and northeast Laos (Belokobylskij et al., 2013; Niisato, 2004; Wickham et al., 2016).

Official Control: Semanotus sinoauster is considered reportable by the USDA-APHIS.

California Distribution:  Semanotus sinoauster is not known to be present in California (Symbiota Collections of Arthropods Network).

California Interceptions:  Semanotus sinoauster has not been intercepted in California (CDFA Pest and Damage Report Database, 2018).

The risk Semanotus sinoauster would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Semanotus sinoauster may be presently limited to areas with a subtropical climate. The available evidence suggests it may feed on two species of Cupressaceae.  Climate may limit the potential distribution of this species in California.  If it is capable of feeding on additional species of Cupressaceae, it may be able to become established in a limited part of California. Therefore, sinoauster receives a Medium (2) 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: Semanotus sinoauster is reported to feed on one species of tree, Cunninghamia lanceolata. It has been tentatively reported to feed on another species in this family as well.  Therefore, it receives a Low (1) 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 Reproductive and Dispersal Potential: Semanotus sinoauster presumably flies, and it could probably be dispersed through movement of infested wood.  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.

3) Economic Impact: Other Semanotus species are reported to attack freshly-killed trees and degrade timber quality.  If sinoauster displays a broader host range in California than it does in its native range, it is possible that it could attack other members of Cupressaceae in CA, including incense cedar (Calocedrus decurrens).  There is no data describing if living or dead trees are attacked by S. sinoauster in its native range.  If living or freshly-killed trees are attacked, this could lower timber crop yield.  If only freshly-killed trees are attacked, this could lower crop quality and could also change normal cultural practices, because the timing of the harvest of timber may have to be changed.  Therefore, it receives a High (3) in this category.

Economic Impact:  A, B, D

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: If Semanotus sinoauster becomes established in California, it will encounter species of trees that are presumably not present in its current area of distribution. If this beetle (1) can attack living trees and (2) is capable of attacking a broader range of hosts than it is currently known to, it could attack other trees in California.  There are rare species of Hesperocyparis in California, for example, the Endangered Santa Cruz cypress (Hesperocyparis abramsiana (C. B. Wolf) Bartel) and the Threatened Tecate cypress (Hesperocyparis forbesii (Jeps.) Bartel) (Calflora).  Trees in the family Cupressaceae are used in ornamental plantings, so if this beetle can attack living trees, it could impact such plantings.    Therefore, it receives a High (3) in this category.

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

Environmental Impact:  B, E

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.

Environmental Impact Score:  3

– 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 Semanotus sinoauster: (11)

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: Semanotus sinoauster 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:

7) The final score is the consequences of introduction score minus the post entry distribution and survey information score: Medium (11)


There is significant uncertainty involved with this proposal.  There is some uncertainty regarding the suitability of California’s climate for Semanotus sinoauster.  This beetle appears to be currently limited to areas with a subtropical climate.  There is also significant uncertainty regarding the possibility of this beetle to attack trees in California.  Most of the possible threats considered in this proposal depend on the possibility of this beetle displaying a broader host range in California than it does in its native range.  If it is indeed restricted to the species it is reported to attack in its native range, it will almost certainly have, at most, a minor impact in the state.  Lastly, there is uncertainty regarding whether or not this beetle attacks living trees.  If it only attacks trees that are already dead, this beetle poses much less of a risk than is reflected in this proposal.

Conclusion and Rating Justification:

Semanotus sinoauster belongs to a genus with species that are reported to attack living trees and also to damage timber.  If this beetle becomes established in California and displays a broader host range here, it would pose an economic and environmental threat to the state.  For these reasons, an “A” rating is justified.


Belokobylskij, S. A., Tang, P., and Chen, X.  2013.  Chinese species of the genus Neurocrassus Šnoflak, 1945 (Hymenoptera: Braconidae: Doryctinae), with a key to Asian species.  Annales Zoologici 63:235-249.

Blay, V. M.  2014.  Estudio de características físicas, biológicas y de movilidad de Semanotus laurasii (Lucas, 1851) (Coleoptera: Cerambycidae).  Masters thesis.  Universitat Politécnica de València.

Calflora. 2018. Information on California plants for education, research and conservation, with data contributed by public and private institutions and individuals.  Accessed May 11, 2018:

CDFA Pest and Damage Report Database.  2018.  Semanotus sinoauster.  Plant Health and Pest Prevention Services. CA Department of Food and Agriculture.  Accessed May 11, 2018:

Cherepanov, A. I.  1988.  Cerambycidae of Northern Asia.  Volume 2, Part 1.  Amerind Publishing Co. Pvt. Ltd., New Delhi.

Martínez-Blay, V., Martínez-Asensio, O., and Soto, A.  2014.  Dinámica estacional, biología y daños ocasionados por Semanotus laurasii (Lucas, 1851) (Coleoptera: Cerambycidae) en cupresáceas de la ciudad de Valencia.  Actas de Horticultura 68:84-89.

Niisato, T.  2004.  Semanotus sinoauster (Coleoptera, Cerambycidae) firstly recorded from Laos.  Elytra 32:437-441.

Shibata, E.  1995.  Reproductive strategy of the Sugi bark borer, Semanotus japonicus

(Coleoptera: Cerambycidae) on Japanese cedar, Cryptomeria japonica.  Researches on Population Ecology 37:229-237.

Symbiota Collections of Arthropods Network.  Accessed May 11, 2018;

Togashi, K.  1985.  Larval size variation of the Cryptomeria bark borer, Semanotus japonicus (Coleoptera: Cerambycidae, in standing trees.  Journal of the Japanese Forestry Society 67:461-463.

Wickham, J. D., Lu, W., Zhang, L. -W., Chen, Y., Zou, Y., Hanks, L. M., and Millar, J. G.  2016.  Likely aggregation-sex pheromones of the invasive beetle Callidiellum villosulum, and the related Asian species Allotraeus asiaticus, Semanotus bifasciatus, and Xylotrechus buqueti (Coleoptera: Cerambycidae).  Journal of Economic Entomology 2016:1-4.

Wickman, B. E.  1965.  Insect-caused deterioration of windthrown timber in northern California, 1963-1964.  Pacific Southwest Forest & Range Experiment Station Research Paper PSW-RP-20:1-14.


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

Responsible Party:

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

Comment Period:* CLOSED

6/28/18 – 8/12/18


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Pest Rating: A


Posted by ls