Clavaspis herculeana (Common Name): Herculeana Scale

California Pest Rating for
Clavaspis herculeana (Common Name): Herculeana Scale
Hemiptera: Diaspididae
Pest Rating: A

Initiating Event:

Clavaspis herculeana is commonly intercepted by CDFA.  A pest rating proposal is required to support its pest rating.

History & Status:

Background:  Clavaspis herculeana is a polyphagous armored scale insect.  It burrows beneath the surface of twigs and branches and feeds by sucking juices from plants while concealed beneath the epidermis of its host-plants1,2. Known hosts include: Anacardiaceae: mango (Mangifera indica1,2), Mangifera cambodiana1,2, Mangifera spp.1,2; Florida poisontree (Metopium toxiferum1,2), ambarella (Spondias dulcis1,2), jocote (Spondias purpurea1,2), Spondias cytherea1,2; Annonaceae: sugar apple (Annona squamosa1,2), soursop (Annona muricata1,2), Annona spp.1,2; Apocynaceae: Plumeria rubra, Plumeria sp. (numerous CDFA interceptions); Bignoniaceae: pink trumpet tree (Tabebuia heterophylla1,2); Bixaceae: buttercup tree (Cochlospermum vitifolium1,2); Caricaceae: papaya (Carica papaya1,2); Euphorbiaceae: tung-oil tree (Aleurites fordii1,2), Aleurites spp.1,2; Fabaceae: sweet acacia (Acacia farnesiana1,2), Acacia flexicaulis1,2, golden shower tree (Cassia fistula1,2), royal Poinciana (Delonix regia1,2), coast coral tree (Erythrina caffra1,2), coral tree (Erythrina indica1,2), Erythrina spp.1,2, Lonchocarpus spp.1,2, Lonchocarpus latifolius1,2, sensitive plant (Mimosa pudica1,2), monkey-pod (Pithecellobium saman1,2); Lauraceae: Cinnamomum sp.1,2, true cinnamon tree (Cinnamomum zeylanicum1,2); Magnoliaceae: southern magnolia (Magnolia grandiflora1,2); Malvaceae: Eriodendron anfractuosum1,2, Eriodendron spp.1,2, Gossypium spp.1,2; Meliaceae: Cedrela toona1,2; Moraceae: common fig (Ficus carica1,2), Ficus spp.1,2, Roxburgh fig (Ficus roxburgii1,2), sacred fig (Ficus religiosa1,2), Ficus capensis1,2, old fustic (Maclura tinctoria1,2), white mulberry (Morus alba1,2); Myristicaceae: Myristica hypargyraea1,2; Myrtaceae: Eugenia spp.1,2; Polygonaceae: Muehlenbeckia sagittiformis1,2; Proteaceae: southern silky oak (Grevillea robusta1,2); Rhizophoraceae: Rhizophora spp.1,2; Rosaceae: loquat (Eriobotrya japonica1,2), pear (Pyrus spp.1,2), rose (Rosa spp.1,2); Rubiaceae: buttonbush (Cephalanthus occidentalis1,2); Rutaceae: Citrus spp.1,2; Salicaceae: poplar (Populus spp.1,2), Xylosma venosum1,2; Santalaceae: Phoradendron randiae1,2; Styracaceae: Halesia spp.1,2; Verbenaceae: Avicennia nitida1,2Clavaspis herculeana may be transported long distances when infested plants or fresh plant parts are moved.

Worldwide Distribution: Clavaspis herculeana is widespread in many parts of the Australasian, Afrotropical, Oriental, Palearctic, and Neotropical regions1,2.  It is present in Mexico, Texas, Florida, and Hawaii1,2.

Official Control: Clavaspis herculeana is listed as a harmful organism by Japan and the Republic of Korea3.

California Distribution Clavaspis herculeana has never been found in the environment of California.

California Interceptions From 1988 through 2015 Clavaspis herculeana was intercepted 45 times by California’s high risk programs, dog teams, and border stations.  Most of these interceptions have occurred on plants or fresh plant parts from Hawaii, primarily Plumeria rubra or Plumeria sp.

The risk Clavaspis herculeana (Herculeana scale) would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Clavaspis herculeana is polyphagous on a wide variety of plants that are widely grown in California and is likely 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: Clavaspis herculeana is known to feed on plants in at least 25 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. Its cryptic habits mean that herculeana scale may easily be dispersed by trade in infested plants without being detected.  Clavaspis herculeana 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: Clavaspis herculeana has not been documented as lowering any crop yields.  It may lower the value of nursery stock by disfiguring plants with its presence and increase fresh fruit production costs.  Herculeana scale is listed as a harmful organism by several of California’s trading partners and its entry to the state may disrupt fresh fruit and nursery stock export markets.  This scale is not expected to change cultural practices, vector other organisms, injure animals, or disrupt water supplies.  Clavaspis herculeana 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: Clavaspis herculeana is not expected to lower biodiversity, disrupt natural communities, or change ecosystem processes.  It is likely to feed on endangered or threatened species including small-leaved rose (Rosa minutifolia). Herculeana scale is not expected to disrupt critical habitats.  It may trigger additional treatment programs in fresh fruit and nursery industries.  It is not expected to significantly impact cultural practices, home/urban gardening, or ornamental plantings.  Clavaspis herculeana 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 Clavaspis herculeana (Herculeana 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: Clavaspis herculeana 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)


Clavaspis herculeana is reported to be associated with the fungus Septobasidium saccardinum1,2.  This relationship is not clear.

Conclusion and Rating Justification:

Clavaspis herculeana has never been found in California and is expected to have significant economic impacts to California’s fresh fruit and nursery industries if it enters the state.  It is also expected to have significant environmental impacts.  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