Mycetaspis personata (Comstock): Masked Scale

California Pest Rating for
Mycetaspis personata (Comstock):  Masked Scale
Hemiptera: Diaspididae
Pest Rating:  A

Initiating Event:

Mycetaspis personata is commonly intercepted at CDFA’s border stations and presently has a temporary Q-rating.  A pest rating proposal is required to assign a permanent pest rating.

History & Status:

Background:  Mycetaspis personata is a polyphagous armored scale insect that typically feeds on leaves1,2.  It has been considered a pest of citrus in Madeira and mango in Egypt1,2.  Known hosts include:  Anacardiaceae: Anacardium spp.1, mango (Mangifera indica1,2), Mangifera spp.1,2, Tapirira guianensis2; Annonaceae: Annona spp.1,2; Arecaceae: Areca spp.1,2, Chrysalidocarpus lutescens1,2, coconut (Cocos nucifera1,2); Cocos spp.1,2, latan palm (Latania sp.1,2); Phoenix spp.1,2, palmetto (Sabal spp.1,2), walking palm (Socratea exorrhiza)2; Bignoniaceae: Catalpa longisiliqua1,2; Bromeliaceae: Tillandsia spp.1,2; Fabaceae: Bauhinia spp.1,2; Guttiferae: Mammea americana2; Lauraceae: Persea spp.1,2; Malpighiaceae: Banisteria laurifolia1,2; Monimiaceae: Tambourissa spp.1,2; Moraceae: Cuban-laurel (Ficus retusa1,2), weeping fig (Ficus benjamina1,2), Ficus spp.1,2; Musaceae: Musa spp.1,2; Myristicaceae: Virola sebifera2; Myrtaceae: Eugenia spp.1,2, pineapple guava (Feijoa selloviana1,2); Oleaceae: jasmine (Jasminum spp.1,2); Rutaceae: Citrus spp.1,2; Sapotaceae: sapote (Achras sapota1,2); Theaceae: Japanese camellia (Camellia japonica1,2).  Mycetaspis personata may be transported long distances with infested plants or fresh plant parts are moved.

Worldwide Distribution: Mycetaspis personata has a widespread distribution in South America and the Caribbean1,2.  It has spread to several African and Asian nations and is established Mexico, Hawaii, and Florida1,2.

Official Control: Mycetaspis personata is listed as a harmful organism by Japan, the Republic of Korea, and Taiwan3.

California Distribution:  Mycetaspis personata has never been detected in the environment of California.

California Interceptions:  Mycetaspis personata is frequently intercepted by CDFA’s border stations and dog teams on fruit.  It is most often intercepted on mango, but has also been intercepted on other fruit including lime, coconut, and avocado.

The risk Mycetaspis personata (masked scale) would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Host plants of Mycetaspis personata are grown throughout California and the scale insect can be expected to establish wherever they are grown. 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: Mycetaspis personata is polyphagous on a wide variety of plants in at least 18 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.  Mycetaspis personata 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: Mycetaspis personata is considered a quarantine pest by several of California’s trading partners.  This insect could disrupt markets for Californian agricultural commodities if it were to establish in the state.  It may also increase crop production costs by triggering additional management practices to ensure that crops are free from the pest.  Mycetaspis personata 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.

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: Mycetaspis personata 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.  It may trigger additional treatment programs in agriculture and by residents who find infested plants unsightly.  Masked scale 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.

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 Mycetaspis personata (Masked Scale): 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: Mycetaspis personata 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 (14)


There have been no recent formal surveys for scale insects in California.  It is possible that mask scale could be established in some localities.

Conclusion and Rating Justification:

Mycetaspis personata has never been found in California and may have significant economic and environmental impacts if it were to establish here. An “A” rating is justified.


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

 2 SEL Catalog.

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,[@]

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Consequences of Introduction:  1. Climate/Host Interaction: [Your comment that relates to “Climate/Host Interaction” here.]

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Pest Rating:  A

Posted by ls