Rufous scale | Pest Rating Proposals and Final Ratings

California Pest Rating for

Selenaspidus articulatus (Morgan): Rufous scale

Hemiptera: Diaspididae

Pest Rating: A

PEST RATING PROFILE

Initiating Event:

Selenaspidus articulatus is frequently intercepted by CDFA. A pest rating proposal is required to support its permanent pest rating.

History & Status:

Background: Selenaspidus articulatus (Rufous scale), also called the West Indies scale, is considered as a serious pest of certain citrus producing areas of South America, West Indies and coastal regions of Peru².

Rufous scale is a highly polyphagous species that can feed on vegetative growth, flowers, fruits and post-harvest stages of its host plants. Species of Citrus are favored hosts of this pest, but it also feeds on members from the families Anacardiaceae, Euphorbiaceae and Palmae. Known hosts include Acalypha, Anacardium, Annona spp., Antidesma, Ardisia, Artocarpus heterophyllus, Arundinaria, Averrhoa spp., Barringtonia, Bauhinia, Bignonia, Brunfelsia, Calathea, Calea, Calophyllum, Camellia sinensis (tea), Carissa, Cassia, Celastrus, Ceratonia, Chrysalidocarpus, Chrysophyllum, Cladoxylon, Cocos nucifera, Codiaeum, Cordyline, Croton, Cycas,Cyperaceae, Decaspermum, Dictyosperma, Dovyalis, Dracaena, Elaeis,Eriobotrya, Eucalyptus, Eugenia, Excoecaria, Ficus, Fortunella,Furcraea, Garcinia, Gardenia, Gliricidia, Hedera, Hedychium, Hevea brasiliensis, Hibiscus, Howea, Hyphaene, Ixora, Jacquemontia, Jasminum, Lagerstroemia, Lantana, Ligustrum, Litchi chinensis, Lonchocarpus, Maclura, Magnolia, Malachra, Mammea, Mangifera indica, Olea europaea, Palmae, Pandanus, Passiflora edulis, Persea americana, Phaseolus, Phoenix dactylifera,Pilea, Plumeria, Rosa, Saccharum officinarum, Sambucus, Schinus, Spondias, Swietenia, Tamarindus, Tambourissa, Tecoma, Theobroma, Thespesia,Tricalysia, Vitis vinifera, Washingtonia and Xanthosoma sagittifolium².

Rufous scale damages both sides of the leaves, but mostly the upper surface exposed to the sun. The damage is caused by sap-depletion, and through injection of toxic saliva, which causes chlorosis and death of plant tissue in the area of penetration. Parasitism is the most successful technique to control this scale².

Worldwide Distribution: Rufous scale is distributed throughout tropical and subtropical regions of the world. It spread through many of the citrus growing countries including Peru, Jamaica, Montserrat, Philippines, Panama, Nicaragua, Solomon Islands, Mozambique, Trinidad and Tobago, Mexico, South Africa, Sri Lanka, Suriname, Taiwan, Togo, Uganda, United Kingdom, Mauritius, Tanzania, Comoros, Grenada, Martinique, Australia, Barbados, Brazil, Cameroon, Costa Rica, Cuba, Ecuador, El Salvador, Kenya, Chad, Madagascar, Eritrea, French Guiana, and Fiji Island³.

In the United States it can be found in Florida and the Virgin Islands.

Official Control: Rufous scale has been listed as a harmful Organism by 11 nations including China, Japan, Paraguay, Guatemala, Venezuela, Chile, India, New Zealand, Vietnam, Republic of Korea and Republic of Bolivia⁵.

California Distribution: Rufous Scale has never found in the environment in California.

California Interceptions: Rufous scale has been intercepted multiple times by CDFA’s border stations and nursery regulatory inspections. Interceptions were typically on plants or plant material imported from South American countries.

The risk Selenaspidus articulatus (Rufous scale) would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Hosts plants of Rufous scale are grown throughout California and this insect presents the possibility of spread and become established wherever the hosts are grown within the state. It receives a High (3) in this category.

Evaluate if the pest would have suitable hosts and climate to establish in California: Score: 3

– 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: Rufous scale is a highly polyphagous species that has been recorded from hosts belonging to 60 genera in 31 plant families⁴. It receives a High (3) in this category.

Evaluate the host range of the pest. Score: 3

– 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: Rufous scale females produce large number of eggs (71-124 each) and can be easily transported with the movement of infested plant material. It receives at High (3) in this category

Evaluate the natural and artificial dispersal potential of the pest. Score: 3

– 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.

3) Economic Impact: Rufous scale is mainly a pest of citrus but also has the potential to devastate California grape, avocado and olive industry. It is listed as a damaging 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 It receives a High (3) in this category

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

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: Rufous scale is not expected to lower biodiversity, disrupt natural communities, or change ecosystem processes. It could affect threatened and endangered species such as Wiggins’ croton

(Croton wigginsii) and small-leaved rose (Rosa minutifolia); it would not be expected to disrupt critical habitats. It is very likely to trigger new treatment programs in citrus, olive & avocado orchards and by residents who find infested plants unsightly. It may also significantly impact ornamental plantings. It receives a High (3) in this category

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

Environmental Impact: C, 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.

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 Selenaspidus articulatus (Rufous scale): High (15)**

–Low = 5-8 points

–Medium = 9-12 points

–High = 13-15 points

6) Post Entry Distribution and Survey Information: Rufous scale has never been found in the environment 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)

Uncertainty:

There are no surveys done recently for the detection. Since most of the host plants are grown throughout California, it could easily spread and get established in the state.

Conclusion and Rating Justification:

Rufous scale has never been found in California and might cause significant economic and environmental impacts if this pest were to get established in California. Currently, an “A” rating is justified.

References:

¹DISCOVERIES IN NATURAL HISTORY & EXPLORATION UCR website. Accessed on 11-15-16. http://www.faculty.ucr.edu/~legneref/biotact/ch-95.htm

²Davidson, J.A. and D.R. Miller, 1990. Ornamental plants. In: D. Rosen (ed.), armoured scale insects, their biology, natural enemies and control. Vol. 4B. Elsevier, Amsterdam, the Netherlands: 603-632 http://wbd.etibioinformatics.nl/bis/diaspididae.php?menuentry=soorten&id=175

³Biological Records Centre: Global Species : Accessed on 11-15-16 http://www.globalspecies.org/ntaxa/385773

⁴USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD). Accessed on 11-15-16. https://pcit.aphis.usda.gov/pcit/

⁵Pest and Damage Record Database, California Department of Food and Agriculture, Plant Health and Pest Prevention Services. http://phpps.cdfa.ca.gov/user/frmLogon2.asp

Responsible Party:

Javaid Iqbal, California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 403-6695; plant.health[@]cdfa.ca.gov.

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