Tag Archives: Soft Scale

Kilifia Americana Ben-Dov | Soft Scale

California Pest Rating for
Kilifia americana Ben-Dov: Soft scale
Hemiptera: Coccidae
Pest Rating: A

Initiating Event:

Kilifia americana was found recently in Monterey County in a nursery. It was intercepted earlier in 90’s and presently has a temporary rating of “Q”. A pest rating proposal is required to support its permanent pest rating.

History & Status:

Background: Kilifia americana is member of the soft scale family Coccidae.  It has broadly oval body, triangular, and narrowly rounded head. Kilifia americana looks flat on leaves and it is pale green or yellow green in color without an obvious wax covering2.

Like other species in the genus Kilifia, it can feed on a variety of cultivated plants. Known hosts include: Anacardiaceae: mango (Mangifera indica); Apocynaceae: pinwheel flower (Tabernaemontana divaricata); Rubiaceae: coffee (Coffea arabica); Rutaceae: citrus (Citrus limon, Citrus maxima & Clausena lansium); Araceae: Dieffenbachia seguine; Arecaceae: Chamaedorea spp.; Euphorbiaceae: Euphorbia spp. and gardenia (Gardenia jasminoides) 3. Its recent finding at a Monterey nursery on orchids (Orchidaceae) constitutes a new host record for this species5.

Worldwide Distribution: Kilifia americana was described from Texas in the United States2 and it is also reported from China and Mexico2. It also has been intercepted on shipments coming from Costa Rica, Honduras, Panama and Puerto Rico2.

Official Control: Kilifia americana is not known to be under official control in any other states or nations7.  However, Arizona maintains a quarantine against all citrus surface pests5.

California Distribution: Kilifia americana has never been found in the environment in California.

California Interceptions: Kilifia americana was found recently at a nursery in Monterey County (PDR 272P06144846)6. It was intercepted two times earlier in 1990’s3.

The risk Kilifia americana (Soft scale) would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Hosts plants of Kilifia americana are growing 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:

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: Kilifia americana has been reported to feed on plants of at least ten genera in eight families, mostly from the tropics1, and it is likely that this host range is much broader than presently known, considering that its closest relative, Kilifia acuminata, is known to feed on over 50 genera4. It receives a High (3) in this category.

Evaluate the host range of the pest.

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 and may disperse long distances when infested plants or plant parts are moved. They may also be spread by wind or by hitchhiking on plants, animals, or equipment. Kilifia americana receives a High (3) in this category.

Evaluate the natural and artificial dispersal potential of the pest.

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: Kilifia americana is not expected to lower the crop yields. It might reduce the value of nursery stock by disfiguring plants with its presence and increase crop production costs in nurseries and orchards. It could also disrupt movement of citrus to Arizona5. It is not expected to change cultural practices, vector other organisms, injure animals, or disrupt water supplies. It receives a Medium (2) in this category. Evaluate the economic impact of the pest to California using the criteria below.

Economic Impact: 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: 2

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.

3) Environmental Impact: Kilifia americana is not expected to lower biodiversity, disrupt natural communities, or change ecosystem processes. No hosts of the scale are listed as threatened or endangered species in California and the scale is not expected to affect critical habitats. It might trigger new chemical treatments in orchards and the nursery industry and by residents who find infested plants unsightly. It is not expected to significantly impact cultural practices, home/urban gardening, or ornamental plantings. It receives a Medium (2) in this category.

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

Environmental Impact:  D

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: 2

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 Kilifia americana (Soft scale):  High (13)

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Kilifia americana 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 (13)


It is likely that the host range of Kilifia americana is greater than presently known. It is possible that if introduced in California it could easily spread and become established in the state.

Conclusion and Rating Justification:

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

  1. Ben-Dov., 1979. A taxonomic study of the soft-scale genus Kilifia (Coccidae). Systematic Entomology 4: 311-324.
  1. Scale insects: Kilifia americana. Accessed on 2-6-17  http://idtools.org/id/scales/factsheet.php?name=6890
  1.  Accessed on 2-6-17  http://scalenet.info/catalogue/Kilifia%20americana/
  1.  Accessed on 2-6-17  http://scalenet.info/catalogue/kilifia%20acuminata/
  1. Summary of Exterior Quarantines.    Arizona Department of Agriculture.  Accessed on 2-6-17. http://nationalplantboard.org/wp-content/uploads/docs/summaries/arizona.pdf
  1. Pest and Damage Record Database, California Department of Food and Agriculture, Plant Health and Pest Prevention Services. http://phpps.cdfa.ca.gov/user/frmLogon2.asp

USDA phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD). Accessed on 2-6-17  https://pcit.aphis.usda.gov/pcit/

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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Pest Rating: A

Posted by ls