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Aonidiella orientalis (Newstead): Oriental Scale


California Pest Rating for
Aonidiella orientalis (Newstead): Oriental Scale
Hemiptera: Diaspididae
Pest Rating:  A


Initiating Event:

Aonidiella orientalis is frequently intercepted by CDFA.  A pest rating proposal is required to support its pest rating.

History & Status:

Background:  Aonidiella orientalis is a highly polyphagous armored scale insect.  It feeds on the leaves of a wide variety of plants and is regarded as an economic pest of citrus, tea, dates, palms, papaya, mango, and ornamentals1.  Known hosts include:  Acanthaceae: Adhatoda vasica1, Barleria cristata1, Thunbergia grandiflora1; Amaranthaceae: Bassia latifolia1; Anacardiaceae: Mangifera indica1, Pistacia integerrima1, Spondias cytherea1; Annonaceae: Annona squamosa1, Annona glabra1, Annona1, Polyalthia korihthi1, Polyathia1, Rollinia emarginata1; Apocynaceae: Alstonia scholaris1, Alstonia1, Calotropis1, Calotropis procera1, Carissa carandas1, Carissa1, Nerium1, Nerium oleander1, Plumeria1, Tabernaemontana coronaria1, Tabernaemontana1; Araliaceae: Hedera1; Arecaceae: Cocos nucifera1, Cocos1, Inodes neglecta1, Loroma amethystiora1, Phoenix1, Phoenix dactylifera1, Phoenix1, Roystonea regia1; Aristolochiaceae: Aristolochia1; Asparagaceae: Agave variegata1, Agave sisalana1, Agave americana1, Agave1; Bignoniaceae: Bignonia vinusta1, Bignonia radicans1, Kigelia pinnata1, Oroxylum indicum1, Tecoma australis1, Tecoma undulata1, Tecoma stans1; Boraginaceae: Cordia rothii1, Cordia myxa1, Cordia1, Cordia obliqua1, Ehretia serrata1; Burseraceae: Boswellia serrata1, Bursera serrata1; Buxaceae: Buxus sempervirens1; Cactaceae: Cactus1, Opuntia1; Cannaceae: Canna indica1; Capparaceae: Crataeva religiosa1; Caprifoliaceae: Lonicera chinensis1, Sambucus javanica1; Caricaceae: Carica papaya1, Carica papaya1; Celastraceae: Catha edulis1, Celastrus paniculata1; Combretaceae: Quisqualis indica1, Terminalia belerica1, Terminalia arjuna1; Convolvulaceae: Calonyction roxburghii1, Ipomoea1, Porana paniculata1; Cunoniaceae: Weinmannia1; Cycadaceae: Cycas revoluta1, Cycas1; Ebenaceae: Diospyros1, Diospyros montana1, Diospyros embryopteris1; Elaeagnaceae: Elaeagnus pungens1; Euphorbiaceae: Acalypha1, Bischofia javanica1, Croton tiglium1, Mallotus philippinensis1, Phyllanthus myrtifolius1, Poinsettia1, Putranjiva roxburghii1, Ricinus1, Ricinus communis1, Sapium sebiferum1; Fabaceae: Acacia cyanophila1, Albizia lebbek1, Albizia1, Atylosia1, Atylosia candollii1, Bauhinia variegata1, Bauhinia1, Bauhinia purpurea1, Bauhinia alba1, Bauhinia vahlii1, Bauhinia racemosa1, Butea frondosa1, Caesalpinia bonducella1, Cassia1, Cassia auriculata1, Cassia fistula1, Ceratonia siliqua1, Dalbergia1, Dalbergia lanceolaria1, Dalbergia sissoo1, Erythrina crista1, Inga dulcis1, Poinciana regia1, Pongamia glabra1, Saraca indica1, Tamarindus1, Tamarindus indica1, Tephrosia1; Heliconiaceae: Heliconia1; Liliaceae: Aloe vera1, Asparagus sprengeri1, Asparagus1; Lythraceae: Lagerstroemia indica1, Lawsonia inermis1, Punica granatum1; Magnoliaceae: Magnolia grandiflora1; Malpighiaceae: Hiptage madablota1; Malvaceae: Adansonia1, Bombax malabaricum1, Eriodendron anfractuosum1, Grewia asiatica1, Hibiscus1, Pterospermum acerifolium1, Sterculia1, Sterculia alata1; Melastomataceae: Osbeckia1, Wrightia coccinea1, Meliaceae: Azedarach indica1, Cedrela toona1, Melia volkensii1, Melia1, Melia indica1, Melia composita1, Melia azadirachta1, Swietenia mahagoni1; Menispermaceae: Cocculus laurifolius1; Moraceae: Broussonetia papyrifera1, Ficus benghalensis1, Ficus salicifolia1, Ficus glomerata1, Ficus infectoria1, Ficus nitida1, Ficus orbicularis1, Ficus palmata1, Ficus religiosa1, Ficus carica1, Ficus retusa1, Ficus roxburghii1, Ficus1, Ficus elastica1, Maclura aurantiaca1, Morus1, Morus alba1, Morus laevigata1; Moringaceae: Moringa pterygosperma1; Musaceae: Musa1, Musa sapientum1; Myrtaceae: Callistemon rigidus1, Eucalyptus1, Eugenia jambolana1, Eugenia1, Myrrhinium rubriflorum1, Myrtus communis1, Psidium guajava1; Nyctaginaceae: Bougainvillea1, Mirabilis jalapa1, Nyctaginia1; Ochnaceae: Ochna squarrosa1; Oleaceae: Jasminum1, Olea europaea1; Orchidaceae: 1; Oxalidaceae: Averrhoa carambola1; Poaceae: Panicum1; Podocarpaceae: Podocarpus neriifolius1, Podocarpus lamberti1; Polygonaceae: Antigonon leptopus1; Proteaceae: Grevillea robusta1; Ranunculaceae: Clematis paniculatus1; Rhamnaceae: Rhamnus persicus1, Ziziphus oenoplia1, Ziziphus1, Ziziphus jujuba1; Rhizophoraceae: Bruguiera sexangulata1, Rhizophora mucronata1; Rosaceae: Eriobotrya japonica1, Prunus armeniaca1, Pyrus sinensis1, Rosa1; Rubiaceae: Stephegyne parviflora1; Rutaceae: Aegle marmelos1, Aegle1, Casimiroa1, Chloroxylon swietenia1, Citrus trifoliata1, Citrus limon1, Citrus aurantium1, Citrus1, Feronia elephantum1, Limonia1, Murraya exotica1, Murraya exotica1; Salicaceae: Populus alba1, Populus euphratica1, Salix tetrasperma1; Santalaceae: Santalum album1; Sapindaceae: Acer pictum1, Acer oblongum1, Dodonaea viscosa1, Litchi chinensis1, Nephelium litchi1, Sapindus detergens1; Sapotaceae: Mimusops elengi1, Mimusops kauki1; Simaroubaceae: Ailanthus aladulosa1; Solanaceae: Solanum melongena1, Solanum arundo1; Theaceae: Camellia1, Thea1; Ulmaceae: Celtis1, Celtis australis1, Ulmus integrifolia1, Ulmus1; Verbenaceae: Callicarpa macrophyla1, Citharexylum subserratum1, Clerodendrum phlomoides1, Duranta ellisi1, Duranta plumieri1, Gmelina arborea1, Nyctanthes arbor-tristis1, Vitex negundo1; Vitaceae: Vitis vinifera1, Zamiaceae: Zamia1; Zingiberaceae: Alpinia nutans1Aonidiella orientalis may be transported long distances when infested plants or fresh plant parts are moved.

Worldwide Distribution: Aonidiella orientalis is presumably native to Asia and has spread through much of the Neotropical, Afrotropical, Palearctic, and Oceanic regions.  In North America it is only known to be established in Florida1.

Official Control: Aonidiella orientalis is listed as a harmful organism by Chile, Colombia, Costa Rica, Honduras, Japan, and the Republic of Korea2.

California Distribution Aonidiella orientalis has never been found in California.

California Interceptions From 1987 through 2015 Aonidiella orientalis was intercepted 225 times by CDFA’s high risk programs, dog teams, and border stations.  Many of these interceptions have been on coconut, papaya, and mango from Florida, Brazil, and Mexico.

The risk Aonidiella orientalis (Oriental scale) would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Due to its highly polyphagous nature and known distribution across a range of climates Aonidiella orientalis can be expected to establish a widespread distribution in California.  It 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: Aonidiella orientalis is known to feed on hundreds of species in at least 67 plant 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 are capable of rapid reproduction and can be transported long distances when infested plants or fresh plant parts are moved.  They may also disperse locally by crawling, wind, or by hitchhiking on clothing, equipment, or animals.  Aonidiella orientalis 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: Aonidiella orientalis is considered an economic pest of several crops that are grown in California and may be expected to lower crop yields and increase crop production costs.  Oriental scale is listed as a harmful organism by several of California’s trading partners.  If the scale were to enter the state it may disrupt markets for fresh fruit and nursery stock.  Aonidiella orientalis receives a High (3) 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: Aonidiella orientalis is not expected to lower biodiversity, disrupt natural communities, or change ecosystem processes.  It may feed on endangered and threatened species such as small-leaved rose (Rosa minutifolia).  Oriental scale is not expected to disrupt critical habitats.  It may trigger additional official or private treatment programs in orchards, the nursery industry, and by residents who find infested plants unacceptable.  Aonidiella orientalis may also significantly impact cultural practices, home/urban gardening, and ornamental plantings.  It receives a High (3) 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 Aonidiella orientalis (Oriental Scale): High (15)

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: Aonidiella orientalis 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 (15)


There have not been any recent surveys for oriental scale in California.  It is possible that it could be established in some localities.

Conclusion and Rating Justification:

Aonidiella orientalis has never been found in California and is likely to have significant economic and environmental impacts if it were to enter the state.  An “A” rating is justified.


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



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.

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Pest Rating:  A

Posted by ls