Coccotrypes rutschuruensis | Pest Rating Proposals and Final Ratings

California Pest Rating for

Bark Beetle | Coccotrypes rutschuruensis Eggers

Pest Rating: A

PEST RATING PROFILE

Initiating Event:

In 1987, beetles were found mining the bases of seedlings of the palm, Howea forsteriana, in Orange County (PDR # 821414). The beetles were identified as Coccotrypes rutschuruensis (misspelled in the PDR as rutshuruensis). This apparently represents the only detection of the species in the United States.

History & Status:

Background: This species has been found associated with the following plants: Annona sp. (Annonaceae), Astrocaryum murumura, Howea forsteriana, Phoenix reclinata (Arecaceae), and Triplochiton scleroxylon (Malvaceae). Wood (2007) considered it possible that what he treated as C. rutschuruensis could have been two or more species. Therefore, the biological data of multiple species may have been combined and the specific identification of members of this genus may be problematic. Regardless, little biological information is available for the beetles that have been referred to by this name except for reports of feeding on the bases of seedlings of Howea forsteriana and in Astrocaryum palm nuts. For both of these reasons (doubtful species identity and poorly-known biology), a cautious approach must be taken and the biology of the entire genus Coccotrypes will be drawn upon in this proposal.

Worldwide Distribution: Coccotrypes rutschuruensis was described from material collected in Rutshuru, Democratic Republic of the Congo, and it is presumably native to that continent. The 1987 Orange County find is apparently the only record of this species in the United States, and it is presumed that this species is not established in this country (Haack and Rabaglia 2013). There are reports that this species has been introduced to Brazil and Suriname (Wood, 2007). Unfortunately, these records may represent one or more different species due to the confused taxonomy.

Official Control: Coccotrypes rutschuruensis is not known to be under official control anywhere.

California Distribution: This species is not known to occur in the United States.

California Interceptions: The above-mentioned detection in Orange County is apparently the only record of this species in California (and the United States).

The risk Coccotrypes rutschuruensis would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: The available distribution records suggest that the species is primarily tropical but may also be capable of establishment in temperate climates, although this depends on the specimens identified as rutschuruensis in South America actually being that species. Because of the lack of biological information available on this species and the doubt regarding the species identities, the broad, collective climatic tolerance of the entire genus Coccotrypes is considered. Regarding host plants, this beetles appears to be mostly restricted to palms. There is only one native palm in California, but many species are planted as ornamentals in the southern half of the state. Therefore, C. rutschuruensis 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: The available feeding records for Coccotrypes rutschuruensis all involve palms, although there is little biological information available. The feeding habits of the entire genus Coccotrypes are considered. Therefore, Coccotrypes rutschuruensis receives a High (3) 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: Coccotrypes species are inbreeding and can reproduce via arrhenotokous parthenogenesis. This means that a single, unfertilized female is capable of founding a population by producing males from unfertilized eggs and mating with them. In addition, Coccotrypes species are known to fly. Therefore, Coccotrypes rutschuruensis receives a High (3) 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: The beetles identified as rutschuruensis were reported feeding on palm seeds and seedlings. It is possible that if it were to become established in California, this beetle could impact the date and ornamental palm industries, including lowering yield and disrupting markets and increasing production costs. Therefore, it receives a High (3) in this category.

Economic Impact: A, B, C

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: Coccotrypes rutschuruensis is reported to feed on palm seeds and seedlings. Another species of Coccotrypes, carpophagus, has been reported to feed on Washingtonia filifera and W. robusta. If introduced into California, C. rutschuruensis could impact the regeneration of the native Washingtonia filifera palm in southern California. This beetle could also impact ornamental palm plantings and trigger treatment programs if planted palms were attacked. 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, D, 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.

Score the pest for Environmental Impact. Score:

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 Coccotrypes rutschuruensis: High (14)**

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: Coccotrypes rutschuruensis been found only once in California (the Orange County find cited above). Because there is no further evidence of this species in the state, 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: High (14)

Uncertainty:

Coccotrypes is diverse (129 described species) and the body size is minute. This makes identification challenging even in a best-case scenario (i.e., if the systematics of the group have been well-studied, or a modern revision existed). In many cases, specimens of Coccotrypes are only identified to the level of genus. This means that, even if C. rutschuruensis was established in the United States, it may not have been identified as that species. In addition, the sparseness of biological data available for this species, along with the doubt regarding its identity, leads the author to consider the biology of the entire genus Coccotrypes in developing a rating.

Conclusion and Rating Justification:

The beetles historically identified as C. rutschuruensis have been reported feeding on palm seeds and seedlings. This raises the possibility of economic and environmental damage if this species became established. There is apparently a possibility that other Coccotrypes species may be referred to as C. rutschuruensis, which means that a specimen intercepted in California and identified as C. rutschuruensis may be a different species with a different biology (including feeding habits and climatic tolerances). For this reason, a cautious approach has been taken. Coccotrypes rutschuruensis deserves an “A” rating.

References:

Atkinson, T.H. 2017. Bark and ambrosia beetles of North and Central America. http://www.barkbeetles.info

Haack, R.A. 2001. Intercepted Scolytidae (Coleoptera) at U.S. ports of entry: 1985-2000. Integrated Pest Management. 6: 253-282.

Haack, R.A. and R.J. Rabaglia. 2013. Exotic bark and ambrosia beetles in the USA: Potential and current invaders. In (J. Peña, ed.): Potential pests of agricultural crops (pp. 48-74). CAB International.

Vega, F.E. and R.W. Hofstetter. 2014. Bark beetles: Biology and ecology of native and invasive species. Academic Press. 640 pp.

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

Wood, S.L. and D.E. Bright. 1992. A catalog of Scolytidae and Platypodidae (Coleoptera), Part 2: Taxonomic index. Great Basin Naturalist Memoirs. 13: 1-1553.

Author:

Kyle Beucke, 1220 N Street, Room 221, Sacramento, CA, 95814, 916-403-6741, plant.health[@]cdfa.ca.gov

Responsible Party:

Jason Leathers, 2800 Gateway Oaks Drive, Sacramento CA 95833, (916) 654-1211; plant.health[@]cdfa.ca.gov.

Comment Period:* CLOSED

1/16/2018 – 3/2/2018

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