Aulacaspis yasumatsui Takagi: Cycad Aulacaspis Scale

California Pest Rating for
Aulacaspis yasumatsui Takagi: Cycad Aulacaspis Scale
Hemiptera: Diaspididae
Pest Rating:  A

 


PEST RATING PROFILE
Initiating Event:

Aulacaspis yasumatsui is frequently intercepted by CDFA and presently has a temporary rating of “Q”.  A pest rating proposal is required to assign a permanent pest rating.

History & Status:

BackgroundAulacaspis yasumatsui is an armored scale insect that is considered a serious pest of cycads in Florida, Hawaii, Guam, Palau, Taiwan and Indonesia1,2,3.  The scale infests both the fronds and the roots of its host plants at depths of up to 60cm in the soil2.  Clean plants that are infested by the scales show chlorotic leaves within a month1.  Both sides of fronds on untreated plants become white with layers of scales1.  Within 270 days plants are heavily desiccated and brown and within a year they are dead1.  Even if infestations are managed they usually reduce the value of nursery stock, as dead scales are difficult to remove from fronds2.  Infestations are also persistent, they likely to return from deep on the roots to the fronds of treated plants2.  Since it feeds deep beneath soil, Aulacaspis yasumatsui can easily be transported long distances when infested host plants are moved.  Known hosts include:  Boweniaceae: Bowenia sp.1; Cycadaceae: Cycas circinalis1, Cycas media1, Cycas micronesica1, Cycas panzhihuaensis1, Cycas revoluta1, Cycas rumphii1, Cycas seemannii1, Cycas sp.1, Cycas szechuanensis1, Cycas taitungensis1, Cycas thouarsii1, Cycas wadei1; Stangeriaceae: Stangeria eripus1, Stangeria sp.1; Zamiaceae: Dioon califanoi1, Dioon edule1, Dioon merolae1, Dioon rzedowski1, Dioon sp.1, Dioon spinulosum1, Dioon tomasellii sonorense1, Diooon sonorense1, Encephalartos barteri1, Encephalartos ferox1, Encephalartos hildebrandtii1, Encephalartos manikensis1, Encephalartos pterogonus1, Encephalartos sp.1, Encephalartos whitelockii1, Macrozamia lucida1, Macrozamia miguelii1, Macrozamia sp.1, Microcycas colocoma1, Microcycas sp.1, Zamia integrifolia1, Zamia loddigesii Miq1.

Worldwide Distribution: Aulacaspis yasumatsui is native to South-East Asia5.  It has spread to Central America, the Caribbean Islands, and parts of the Pacific Region and Australasia.  It was first found in Florida in 19961,2 and has since spread through much of the southeastern United States, Hawaii, Guam and Palau.

Official Control: Aulacaspis yasumatsui is listed as a harmful organism by Japan, the Republic of Korea, New Zealand, and Seychelles4.

California DistributionAulacaspis yasumatsui has never been found in the environment of California.

California Interceptions:  Between January 1, 2000 and December 31, 2014 Aulacaspis yasumatsui was intercepted 221 times by CDFA’s high risk programs, border stations, dog teams, and nursery inspections.  Most of these interceptions have been on cycads from Hawaii and Florida.  Since 2009, heavy infestations of the scale have been found several times in southern California nurseries.

The risk Aulacaspis yasumatsui (cycad aulacaspis scale) would pose to California is evaluated below.

Consequences of Introduction: 

1)  Climate/Host Interaction: Cycads are popular ornamental plants that are grown throughout much of California. Aulacaspis yasumatsui is likely able to establish wherever these hosts are grown.  The scale 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: Aulacaspis yasumatsui is known to feed on plants in eight genera in four families.  It receives a Medium (2) 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: Aulacaspis yasumatsui has a high reproductive rate.  It can complete a generation in 28-41 days and each female lays about 100 eggs1,2.  The scale also has high dispersal potential.  It can be transported long distances on infested plants and can disperse locally by crawling, by wind, or by hitchhiking on clothing, equipment, or animals.  Aulacaspis yasumatsui 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: If Aulacaspis yasumatsui were to establish in California it would be certain to lower yields in cycad nursery stock production and reduce the value of cycad nursery stock.  It might also trigger disruptions of markets for nursery stock.  Aulacaspis yasumatsui 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: Cycads are popular, high-value ornamental plants in California and if Aulacaspis yasumatsui were to establish in the state these plants would require new treatment programs.  These would be necessary in both the nursery industry and by residents who wish to keep cycads alive.  Aulacaspis yasumatsui would significantly impact cultural practices, home/urban gardening, and ornamental plantings.   The scale 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 Aulacaspis yasumatsui (Cycad Aulacaspis 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: Aulacaspis yasumatsui has not been found in the environment of 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)

Uncertainty:

Aulacaspis yasumatsui commonly infests roots of host plants which can make it difficult to observe during visual inspections.  The frequent interceptions, heavy infestations found in southern California nurseries, and below ground feeding make it possible that some infested plants have been sold to consumers.  Furthermore, there have been no recent surveys of cycad pests.  It is possible that Aulacapis yasumatsui may already be found in some locations in California’s environment.

Conclusion and Rating Justification:

Aulacaspis yasumatsui has not been found in the environment of California and would have significant economic and environmental impacts if it were to establish here.  An “A”-rating is justified.

References:

1 SEL Catalog Query Results.  http://www.sel.barc.usda.gov/catalogs/diaspidi/Aulacaspisyasumatsui.htm

2 Weissling, T.J. and F.W. Howard. 2013. University of Florida Featured Creatures: Common Name: Cycad Aulacaspis Scale.  http://entnemdept.ufl.edu/creatures/orn/palms/cycad_scale.htm

3 Cave, R.D., Chao, J-T., Kumashiro, B., Marler, T., Miles, J., Moore, A., Muniappan, R., and Watson, G.W. (2013) Status and biological control of cycad aulacaspis scale. Biocontrol News and Information, 34(1): 1N-4N.

4 USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD).  https://pcit.aphis.usda.gov/pcit/

5 CABI Invasive Species Compendium: Aulacaspis yasumatsui (cycad aulacaspis scale).  http://www.cabi.org/isc/datasheet/18756

Responsible Party:

Jason Leathers, 1220 N Street, Sacramento, CA, 95814, (916) 654-1211, plant.health[@]cdfa.ca.gov.


Comment Period:  CLOSED

The 45-day comment period opened on Tuesday,  April 7, 2015 and closed on May 22, 2015.


Pest Rating:  A


Posted by ls