Boxwood Scale | Pinnaspis buxi (Bouche)

California Pest Rating
Pinnaspis buxi (Bouché): Boxwood Scale
Hemiptera: Diaspididae
Former Pest Rating: A
Current Pest Rating: A
Initiating Event:

Pinnaspis buxi is frequently intercepted by CDFA.  A pest rating proposal is required to support its permanent pest rating.

History & Status:

BackgroundPinnaspis buxi is a widespread, polyphagous armored scale insect that feeds on a wide variety of hosts.  Known hosts include Apocynaceae: Nerium odorum1,2; Aquifoliaceae: Ilex vomitoria1,2; Araceae: Aglaonema philippinensis1,2, Alocasia sp.1,2, Anthurium magnificum1,2, Anthurium crystallinum1,2, Anthurium grandi1,2, Anubias sp.1,2, Colocasia esculenta1,2, Epipremnum sp.1,2, Homalomena philippinensis1,2, Monstera deliciosa1,2, Monstera sp.1,2, Philodendron sp.1,2, Philodendron pertusum1,2, Pothos seemanii1,2, Rhodospatha sp.1,2, Scindapsus sp.1,2, Scindapsus aureus1,2, Spathiphyllum sp.1,2; Arecaceae: Acrocomia sp.1,2, Acrocomia media1,2, Areca lutescens1,2, Areca catechu1,2, Areca sp.1,2, Calamus sp.1,2, Chamaerops sp.1,2, Chrysalidocarpus lutescens1,2, Cocos nucifera1,2, Daemonorops lewisianus1,2, Dictyosperma sp.1,2, Dictyosperma album1,2, Howeia forsteriana1,2, Howeia belmoreana1,2, Licuala grandis1,2, Neodypsis1,2, Phoenix sp.1,2, Pinanga kuhlii1,2, Raphia sp.1,2, Rhapis sp.1,2, Tachycarpus sp.1,2, Thrinax excelsa1,2, Trachycarpus sp.1,2, Veitchia joannis1,2; Asteraceae: Chrysanthemum morifolium1,2; Bromeliaceae: Tillandsia sp.1,2, Vriesea polonia1,2; Burseraceae: Canarium commune1,2; Buxaceae: Buxus sp.1,2, Buxus sempervirens1,2; Celastraceae: Siphonodon celastrineus1,2; Cucurbitaceae: Momordica charantia1,2, Momordica sp.1,2; Cupressaceae: Cunninghamia sp.1; Cyperaceae: Cyperus alternifolius1,2; Ebenaceae: Diospyros sp.1,2, Diospyros oleoides1,2; Euphorbiaceae: Aleurites montana1,2, Hevea brasiliensis1,2; Fabaceae: Cassia fistula1,2, Hardwickia binata1,2, Inocarpus fagifer1,2, Kentia sp.1,2, Phaseolus vulgaris1,2, Tamarindus indica1,2; Heliconiaceae: Heliconia bihai1,2, Heliconia sp.1,2; Iridaceae: Dietes bicolor2, Moraea bicolor1; Juncaceae: Prinonium sp.1,2; Lecythidaceae: Barringtonia edulis1,2; Liliaceae: Aloe sp.1,2, Cordyline terminalis1,2, Cordyline fruticosa1,2, Dracaena sp.1,2; Lythraceae: Punica granatum1; Magnoliaceae: Magnolia glandiflora1,2, Michelia chambaka1,2; Malvaceae: Gossypium barbadense1,2, Hibiscus arnottianus1,2, Hibiscus sp.1,2, Sida sp.2, Theobroma cacao1; Marantaceae: Maranta sp.1,2; Meliaceae: Dysoxylum sp.2, Sandoricum sp.1,2, Trichilia sp.1,2; Moraceae: Artocarpus integrifolia1,2, Artocarpus heterophyllus1,2, Ficus glomerata1,2; Musaceae: Musa sp.1,2; Ochnaceae: Schuurmansia sp.1,2; Oleaceae: Olea cuspidata1,2, Olea sp.1,2; Orchidaceae: Dendrobium sp.1,2, Epidendrum sp.1,2; Pandanaceae: Pandanus sp.1,2, Pandanus conideus1,2, Pandanus hornei1,2, Pandanus odoratissimus1,2, Pandanus seychellarum1,2, Pandanus upoluensis1,2, Pandanus utilis1,2; Pinaceae: Pinus sp.1,2; Piperaceae: Piper sp.1,2; Polypodiaceae: Asplenium sp.1,2; Proteaceae: Helicia sp.1,2; Pteridaceae: Adiantum aethiopicum1,2; Rubiaceae: Coprosma laevigata1,2, Morinda citrifolia1,2; Rutaceae: Citrus sp.1,2; Smilacaceae: Smilax sp.1,2; Solanaceae: Lycopersicon esculentum1,2; Strelitziaceae: Strelitzia sp.1,2, Strelitzia reginae1,2; Thymelaeaceae: Daphne oleoides2; Ulmaceae: Celtis philippinensis1,2; Verbenaceae: Lantana commersoni1,2.  The scale can spread long distances when infested plants or plant products are moved in commerce.

Worldwide Distribution: Pinnaspis buxi is widespread in Afrotropical, Australasian, Nearctic, Neotropical, Oriental, and Palearctic regions2.  In the United States it can be found in Florida, Massachusetts, New York, Pennsylvania, Puerto Rico & Vieques Island, the U.S. Virgin Islands, Guam, and the Hawaiian Islands2.

Official Control: Pinnaspis buxi is listed as a quarantine pest by Costa Rica, Japan, New Zealand, and Seychelles.

California Distribution Pinnaspis buxi has never been found in the environment of California.

California Interceptions:  Pinnaspis buxi is commonly intercepted.  Between January 1, 2000 and December 4, 2014 the scale was intercepted 857 times.  Interceptions were typically on plants or plant material imported from Hawaii, Costa Rica, and Florida.

The risk Pinnaspis buxi (boxwood scale) would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Pinnaspis buxi is highly polyphagous and feeds on a wide variety of plants, many of which are grown in California. The scale is likely able to establish wherever host plants are grown.  Boxwood scale receives a High(3) 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: Pinnaspis buxi feeds on a wide variety of plants in at least 44 families.  It receives a High(3) 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: Scale insects have high reproductive rates.  They may spread long distances when host plants are moved.  Furthermore, they may spread by wind or by hitchhiking on clothing, animals, or equipment.  Pinnaspis buxi 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: Despite the worldwide distribution and polyphagous nature of Pinnaspis buxi it does not appear to be documented as causing economic damage.  Nevertheless, it is listed as a quarantine pest by several nations so it has the potential to trigger a loss of markets.  Furthermore, it may increase production costs in citrus and in nursery industries as growers may treat to ensure fruit or plant cleanliness.  Pinnaspis buxi 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.

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: Pinnaspis buxi is not expected to lower biodiversity, disrupt natural communities, or change ecosystem processes.  It is not expected to directly affect threatened or endangered species or disrupt critical habitats.  The scale may trigger additional chemical treatment programs by the citrus and nursery industries and by residents who find infested plants unsightly.  It is not expected to significantly impact cultural practices, home/urban gardening, or ornamental plantings.  Boxwood scale 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 Pinnaspis buxi (Boxwood Scale):  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: Pinnaspis buxi has never been found in California and receives a Not established (0) 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: High(13)


Pinnaspis buxi is commonly intercepted.  It is likely that the scale has entered California many other times and escaped detection.  There have been no formal surveys for this scale in the state.  It is therefore possible that it could be present in some locations in California.

Conclusion and Rating Justification:

Pinnaspis buxi is a polyphagous scale that may has never been found in the environment of California.  If it were to enter the state, it could be expected to have economic impacts in the nursery and citrus industries.  It may also have environmental impacts by triggering new chemical treatments.  An “A”-rating is justified.


1Miller, Dug, Yair Ben-Dov, Gary Gibson, and Nate Hardy.  ScaleNet.

2SEL Catalog query results:

3 USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD).

Responsible Party:

Jason Leathers, 1220 N Street, Sacramento, CA, 95814, (916) 654-1211,[@]

Comment Period:  CLOSED

9/23/2016  11/7/2016

Pest Rating: A