Dactylotrypes longicollis (Wollaston): Beetle

California Pest Rating
Dactylotrypes longicollis dorsal Collected off of Trithrinax brasiliensis (Image Citation: Steven Valley, Oregon Dept of Ag, Bugwood.org)
Dactylotrypes longicollis dorsal Collected off of Trithrinax brasiliensis
(Image Citation: Steven Valley, Oregon Dept of Ag, Bugwood.org)
Dactylotrypes longicollis (Wollaston): Beetle
Coleoptera: Curculionidae
Current Pest Rating:  Z
Proposed Pest Rating:  C
FINAL Pest Rating:  C
Initiating Event:

On October 13, 2015 Dr. Andrew Cline identified two beetles collected from a Lindgren funnel trap as Dactylotrypes longicollis.  A pest rating proposal is required to assign a permanent pest rating.

History & Status:

BackgroundDactylotrypes longicollis feeds on the seeds of palms including wooly jelly palm (Butia eriospatha), Mediterranean fan palm (Chamaerops humilis), Canary Island date palm (Phoenix canariensis), date palm (Phoenix dactylifera), Senegal date palm (Phoenix reclinata), Brazilian needle palm (Trithrinax brasiliensis), and lady palm (Rhapis excelsa)1.  The beetle may be transported long distances when infested palm seeds or plants are moved.

Worldwide Distribution: Dactylotrypes longicollis is native to the Canary Islands and Madeira1.  From there it has spread to France, Italy, mainland Spain, and the Slovak Republic1.

Official Control: Dactylotrypes longicollis is not known to be under official control in any states or nations.  Dactylotrypes spp. are listed as harmful organisms by Peru2.

California DistributionDactylotrypes longicollis has only been found in Fullerton (Orange County), San Marino (Los Angeles County), and Carpinteria (Santa Barbara County).

California InterceptionsDactylotrypes longicollis has not been found in any regulatory situations in California.

The risk Dactylotrypes longicollis would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: The known hosts and natural geographic range of Dactylotrypes longicollis indicate that the beetle is likely to be limited to southern California1.  It receives a Medium (2) in this category.

Evaluate if the pest would have suitable hosts and climate to establish in California.  Score:

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: Dactylotrypes longicollis is only known to feed on the seeds of seven species of palms.  It receives a Low (1) in this category.

Evaluate the host range of the pest. Score:

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: The biology of Dactylotrypes longicollis has not been well documented.  It is assumed to have a high reproductive rate and to be capable of dispersing long distances when infested palm fruit or plants are moved.  It receives a High (3) in this category.

Evaluate the natural and artificial dispersal potential of the pest. Score:

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: The California date industry produces over 40 million pounds of dates annually and employees 2,500 people.  Dactylotrypes longicollis is not known to be established in major date producing nations and it is uncertain if the industry will be affected.  It is possible that the beetle could reduce crop yield or increase crop production costs.  The beetle is not expected to disrupt markets, change cultural practices, vector other organisms, injure animals, or disrupt water supplies.  It receives a Medium (2) in this category.

Evaluate the economic impact of the pest to California using the criteria below. Score:

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.

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: In California Dactylotrypes longicollis is not expected to lower biodiversity, disrupt natural communities, or change ecosystem processes.  It is not likely to affect threatened or endangered species or disrupt critical habitats.  It could trigger new treatment programs in the date industry.  It is not expected to impact cultural practices, home/urban gardening, or ornamental plantings.  Dactylotrypes longicollis receives a Medium (2) in this category.

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

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:

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 Dactylotrypes longicollis: Medium (10)

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: Dactylotrypes longicollis is known to be established in Orange, Los Angeles, and Santa Barbara counties. It receives a Medium (-2) in this category.

Evaluate the known distribution in California. Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included.

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: Low (8)


We do not know how effective the Lindgren funnel is at detecting Dactylotrypes longicollis.  It is quite possible that the beetle is much more widespread in California.

Conclusion and Rating Justification:

Dactylotrypes longicollis has been established across much of southern California since before 2009.  No economic or environmental impacts have been attributed to the beetle.  A “C” rating is justified.


1 LaBonte, James R. and Curtis Y. Takahashi. 2012. Dactylotrypes longicollis (Wollaston) (Coleoptera: Curculionidae: Scolytinae): an exotic bark beetle new to California and North America.  Pan-Pacific Entomologist. 88(2): 222-230 http://www.bioone.org/doi/abs/10.3956/2012-18.1

2 USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD).  https://pcit.aphis.usda.gov/pcit/

Responsible Party:

Jason Leathers, 1220 N Street, Sacramento, CA, 95814, (916) 654-1211, plant.health[@]cdfa.ca.gov.

Comment Period:

The 45-day comment period opened on Wednesday, October 21, 2015 and closed on December 5, 2015.

Pest Rating:  C