Bamboo Pit Scale | Bambusaspis miliaris

California Pest Rating for
Bamboo pit scale | Bambusaspis miliaris (Boisduval)
Hemiptera: Asterolecaniidae
Pest Rating: B




Initiating Event:

Bambusaspis miliaris has been collected multiple times in California.  It is currently Q-rated, and a permanent pest rating proposal is required to support an official pest rating.

History & Status:

Background:  Bambusaspis miliaris is a tiny (adult females measure up to 1.4 millimeters in length) pit scale insect that is covered with a slightly flattened or convex cover that is green, brown, or pale yellow in color, and has a fringe of pale wax filaments (García Morales et al., 2016; Russell, 1941).  Bambusaspis miliaris apparently feeds only on bamboo and is found on the stems and both sides of the leaves of these plants.  Reported host bamboo genera are Arundinaria, Bambusa, Dendrocalamus, Oxytenanthera, Phyllostachys, and Schizostachyum (Ben-Dov, 2006; Russell, 1941).  It should be noted that the genus Bambusa has been split, so the host range may be greater than indicated here.  No reports were found indicating that this scale is a significant pest in California.

Worldwide Distribution:  The origin of Bambusaspis miliaris appears to be in doubt, but it was originally described in 1869 based on material from Algeria, and it may be native to Africa.  This scale is currently widespread in distribution and reported from Bermuda, the Caribbean (including Cuba, Jamaica, and Puerto Rico), the United States, Mexico, Central America (including El Salvador and the Panama Canal Zone), South America (Colombia, Guyana, Suriname, and Venezuela), Africa (including Algeria, Angola, and Morocco), Europe (Canary Islands, and in greenhouses in France), Mauritius, Réunion Island, Southern Asia (Burma, southern China, India, Pakistan, Philippines, Sri Lanka, and Taiwan), Australia, Fiji, Niue, Samoa, and Tonga (Ben-Dov, 2006; Germain et al., 2002; Germain et al., 2014; Monarch, 2017; Pellizzari and Porcelli, 2017; Russell, 1941; Stumpf and Lambdin, 1999; Symbiota Collections of Arthropods Network; Varshney, 1992; Wyckhuys et al., 2013).  In the United States, it is present in Florida, Georgia, Hawaii, and California and in greenhouses in Illinois (Miller et al., 2005; Symbiota Collections of Arthropods Network).

Official Control: Bambusaspis miliaris is not known to be under official control anywhere.

California Distribution:  Pest and Damage Record Database and collection records suggest it is present in Contra Costa, Orange, and San Diego counties.  However, it has not been verified that these finds represent established populations (Monarch, 2017; Pest and Damage Record Database; Symbiota Collections of Arthropods Network).  There is greater confidence that this scale is established in southern California, because most of the finds are from there, as opposed to the single Contra Costa County record.

California Interceptions:  Bambusaspis miliaris has been intercepted frequently on bamboo and unidentified plants from Florida and Hawaii between 1990 and 2017 (PDR # 863733, 1223332, 023344, 1145117, 1070615, 954461, 982835, 965679, 965093, 965181, 1367488, 1254656, 1316253, 1436777, 1436483, 070P06223630, 370P06144368, 400P06775061, 190P06059264, 190P06059253, 19TP06177184).  This scale has been found on bamboo at nurseries in Orange, Riverside, and San Diego counties between 1989 and 2017 (PDR # 830364, 1544578, 1316260, 1544048, 1397024, 1254530, 300P06298425, 300P06298415, 300P06194857, 300P06040168, 300P06040167, 300P06040163, 300P06040160, 300P06040156, 300P06040119, 1609243, 300P06040056, 1609240, 300P06040055, 1609320, 300P06610100, 331P06200175, 331P06143313, 370P06227605, 370P06227606, 331P06142882, 370P06228244, 370P06228245), and it has been found on bamboo in gardens, a park, and a recreation area in Contra Costa, Orange, and San Diego counties between 2000 and 2017 (PDR # 041454, 1395276, 331P06141874, 300P06610109, 300P06610108, 300P06610128, 300P06610082) (Pest and Damage Record Database).

The risk Bambusaspis miliaris would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Bambusaspis miliaris appears to be mostly restricted to areas with a tropical or subtropical climate, although the Contra Costa record suggests it may be able to tolerate more temperate climates. This scale feeds on bamboo.  Bamboo is planted widely in California, but nevertheless, this suggests that cultivated landscapes are required by this scale rather than native vegetation.  This scale may be able to become established in a larger, but still limited portion of California.  Therefore, Bambusaspis miliaris 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: Bambusaspis miliaris appears to be restricted to five genera of bamboo, although some host plants were not identified. 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 Dispersal Potential: Bambusaspis miliaris has a demonstrated ability to disperse and expand in distribution.  It has been spread to many new localities.  The most effective means of dispersal is probably through transport of infested plant material.  The scale is tiny and is probably not easily detected.  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: Asterolecaniids damage plants in two ways.  First, they feed on the sap, and second, they excrete honeydew.  This honeydew can lead to the growth of molds, which can reduce photosynthesis.  Infestations of miliaris detract from the appearance of bamboo, and this could increase production costs (Ben-Dov, 2006).  Therefore, it receives a Low (1) in this category.

Economic Impact:  B

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: 1

– 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: Bamboo is grown and sold widely in California and it is a popular landscaping plant. If Bambusaspis miliaris became established in this state, it could impact ornamental plantings and trigger treatments.   Therefore, it receives a High (3) in this category.

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

Environmental Impact: 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:

– 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 Bambusaspis miliaris: Medium (9)

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: Pest and Damage Record Database and collection records suggest that B. miliaris may be present outdoors in Contra Costa, Orange, and San Diego counties.  It has not been verified that these finds represent established populations, but for the purposes of this proposal, it will be assumed that B. miliaris is established in these three counties.  Therefore, it receives a Low (-1) 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: Low (8)


No reports were found indicating the severity of damage caused by B. miliaris.  The climatic tolerances of this scale are also somewhat ambiguous.  On one hand, the distribution of this scale is mostly restricted to tropical and subtropical areas.  This suggests it may only be capable of becoming established in coastal southern California.  However, if the Contra Costa County record represents an establishment, this indicates that this species has broader climatic tolerances, and it could potentially establish over a much wider area in the state.  A survey targeting this species has not been conducted (N. von Ellenrieder, pers. comm.).

Conclusion and Rating Justification:

Bambusaspis miliaris is apparently established in a limited portion of southern California and possibly in Contra Costa County as well.  Of the seven PDR records that are considered here to possible represent the establishment of this species in California, five are from 2013 or later.  There are no reports of this scale causing significant damage to bamboo in the state.  However, it is possible that the full pest potential of this scale has not been realized, because it was (apparently) so recently established here, and it is still (apparently) so limited in distribution.  It is possible that a lower rating will be proposed in the future, but at the current time, a “B” rating is justified.


Ben-Dov, Y.  2006.  A systematic catalogue of eight scale insect families (Hemiptera: Coccoidea) of the world: Aclerdidae, Asterolecaniidae, Beesoniidae, Carayonemidae, Conchaspididae, Dactylopiidae, Kerriidae and Lecanodiaspididae.  Elsevier.  388 pp.

García Morales, M., Denno, B.D., Miller, D.R., Miller, G.L., Ben-Dov, Y., and Hardy, N.B. 2016.  ScaleNet: A literature-based model of scale insect biology and systematics. Database. doi: 10.1093/database/bav118.  Accessed December 29, 2017

Germain, J.F., Matile-Ferrero, D., Picart, J.L., Delvare, G., and Piron, N.  2002.  Inventaire des cochenilles présentes sous serre en France et connaissance de leurs parasitoides, un préalable au développement de la lute biologique.  AFPP – 6ème Conférence Internationale sur les Ravageurs en Agriculture.  Montpellier, 4-5-6 Décembre 2002.

Germain, J.F., Minatchy, J., Pastou, D., Bagny, P., Mérion, S., Pallas, R., Quilici, S., and Matile-Ferrero, D.  2014.  An updated checklist of the scale insects from Réunion Island (Indian Ocean).  Acta Zoologica Bulgarica.  Supplement.  6: 21-27.

Miller, D.R., Miller, G.L., Hodges, G.S., and Davidson, J.A.  2005.  Introduced scale insects (Hemiptera: Coccoidea) of the United States and their impact on U.S. agriculture.  Proceedings of the Entomological Society of Washington.  107(1): 123-158.

Monarch. 2017.  Accessed December 28, 2017. http//

Pellizzari, G. and Porcelli, F.  2017.  Aspidiotus bornmuelleri Lindinger, 1911, rev. comb.  (Hemiptera: Coccomorpha: Diaspididae), a neglected endemic species from Macaronesia, with comments on the genus Cryptophyllaspis, and further notes on the scale insect fauna of Canary Islands, Spain.  Zootaxa.  4300 (1): 099-110.

Pest and Damage Record Database, California Department of Food and Agriculture, Plant Health and Pest Prevention Services. Accessed December 29, 2017.

Russell, L.M.  1941.  A classification of the scale insect genus Asterolecanium.  United States Department of Agriculture Miscellaneous Publication 424.  United States Department of Agriculture.  322 pp.

Stumpf, C.F. and Lambdin, P.L.  1999.  Taxonomic status of Bambusaspis miliaris, B. robusta, and B. pseudomiliaris (Hemiptera: Coccoidea: Asterolecaniidae).  Insecta Mundi.  13 (3-4): 205-211.

Symbiota Collections of Arthropods Network.  Accessed December 28, 2017.

Varshney, R.K.  1992.  A check list of the scale insects and mealy bugs of South Asia.  Part 1.  Zoological Survey of India Occasional Paper.  139: 1-152.

Wyckhuys, K.A.G., Kondo, T., Herrera, B.V., Miller, D.R., Naranjo, N., and Hyman, G.  2013.  21: Invasion of exotic arthropods in South America’s biodiversity hotspots and agro-production systems.  In (J. Peña, ed.): Potential pests of agricultural crops (pp. 373-400).  CAB International.


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,[@]

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Pest Rating: B


Posted by ls