Gymnaspis aechmeae Newstead: Fly Speck Scale

California Pest Rating for

Gymnaspis aechmeae Newstead: Fly Speck Scale

Hemiptera: Diaspididae

Pest Rating: B

PEST RATING PROFILE

Initiating Event:

On October 28, 2013 Dr. Gillian Watson identified fly speck scale, Gymnaspis aechmeae, from a sample of bromeliad plants submitted from a resident’s greenhouse in Orange County (PDR 300P06040190). Stephen Brown recommended that the scale be run through the draft pest rating process.

History & Status:

Background: Known colloquially in Australia as “the scourge of the bromeliads,⁴” fly speck scale is considered to be a serious pest of the plants^1,2,4,5,6. Known hosts include up to 35 species of Bromeliaceae: Acanthostachys sp., Acanthostachys strobilacea, Aechmea angustifolia, A. aquilega, A. bracteata⁷, Aechmea chantini, A. nidularioides, A. pubescens, Aechmea sp., Ananas comosus, A. sativus, Ananas sp., Aregelia sp., Billbergia nutans, B. leopoldi, B. pyramidalis⁷, B. saundersii, Billbergia sp, Bromelia serra, B.pinguin², Bromelia sp., Hogenbergia erythrostachya, H. stellata⁷, Hogenbergia sp., Karatas amazonica, Karatas sp., Neoregelia sp., Nidularium princeps, Nidularium sp., Pitcairnia sp., Quesnelia sp., Quesnelia wittmackiana, Tillandsia sp., Vriesea sp., Vriesia platzmanni. Other occasional hosts include Monstera sp. (Araceae), Asparagus sprengeri (Asparagaceae), Caraguata weilbachii and Chlorophytum sp. (Liliaceae), Villarsia officinalis (Menyanthaceae), and Cymbidium sp. (Orchidaceae)¹. Fly speck scale can be dispersed long distances in the trade of live plants.

Worldwide Distribution: The native range of fly speck scale is uncertain. It was first discovered on Aechmea aquilegia at Kew Gardens, London, in 1897¹. It was found in Spain by 1906¹, Argentina by 1907¹, and Florida in 1917⁵. It has since been found in Brazil, Costa Rica, Puerto Rico, Cuba², Hawaii, Japan³, Australia^4,6, and in many European nations¹. Within the United States it has also been found in additional eastern and southern states (Alabama, District of Columbia, Florida, Louisiana, Maryland, Missouri, New Jersey, New York, Pennsylvania and West Virginia) and Colorado⁸.

Official Control: Fly speck scale is listed as a quarantine pest in Japan and the Republic of Korea⁹.

California Distribution: Fly speck scale has never been found outdoors in California.

California Interceptions: Fly speck scale was found once in a nursery in San Diego county in 2012 (PDR 1422842).

The risk fly speck scale (Gymnaspis aechmeae) would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Known outdoor habitats of fly speck scale correspond with tropical, humid environments. The scale is not likely to establish outdoors in California. However, bromeliads are produced and kept in greenhouses and the scale is likely to establish in these environments. Fly speck scale receives a Low(1) 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: Fly speck scale is primarily a pest of bromeliads, but it has been found on 41 species in 6 plant families. The scale 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: Fly speck scale has only 2 generations per year¹, but can produce many first instar crawlers (rather than eggs) giving the species high reproductive potential. The crawlers are able to walk between plants⁶. Furthermore, they can be spread long distances when plants are traded, on clothing, or by wind⁶. Fly speck scale 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: Bromeliads are produced in the nursery industry of California. Fly speck scale is likely to lower the value of this crop by disfiguring the plants with their unsightly presence. The scale may also increase crop production costs as nurseries are likely to treat infestations or to treat preventively. Fly speck scale is listed as a quarantine pest by Japan and Korea⁹ so its presence in California could disrupt trade with those markets. Fly speck scale may also negatively change normal cultural practices in botanical gardens and nursery greenhouses. The scale is not expected to lower crop yield, trigger a loss of markets, vector other organisms, affect agriculturally important animals, or affect the water supply. Fly speck scale 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 o rganism.
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: The presence of Gymnaspis aechmeae can be expected to trigger regular, preventive private chemical treatment of bromeliads to prevent unsightly plants⁴and eradicate known infestations. Fly speck scale can also be expected to impact cultural practices in home/urban gardening as bromeliad collectors institute quarantine treatments as they acquire new plants⁴ and discard untreated, infested plants. The scale 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. Fly speck 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 Fly Speck Scale (Gymnaspis aechmeae): Medium (12)**

–Low = 5-8 points
–Medium = 9-12 points
–High = 13-15 points

6) Post Entry Distribution and Survey Information: Fly speck scale is known only from a single incursion into California in a greenhouse in Orange County in 2013. It has not been found anywhere else since then. It 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:

7) The final score is the consequences of introduction score minus the post entry distribution and survey information score: Medium(12)

Uncertainty:

Bromeliad enthusiasts may trade plants frequently and order plants from infested areas via the Internet and mail services; the scale could have a much wider distribution in California.

Conclusion and Rating Justification:

California’s climate is expected to limit the distribution of fly speck scale to greenhouse environments. There, the introduction of the scale is expected to have a significant economic impact by decreasing the value of contaminated bromeliads and increasing production costs. Fly speck scale is also expected to have a significant environmental impact as it can be expected to trigger additional private chemical treatments as residents attempt to both eradicate and prevent infestations. It will also alter cultural practices as residents will quarantine newly acquired plants and dispose of plants that become unsightly. A “B” rating is justified for Gymnaspis aechmeae.

References:

¹http://www.sel.barc.usda.gov/catalogs/diaspidi/Gymnaspisaechmeae.htm

²Novoa, N.M., G.S. Hodges, M.V. Rubio, P.C. Bonnin, and P.H. Oliver. 2010. Nuevos registros de insectos escamas (Hemiptera: Sternorrhyncha: Coccoidea) para Cuba. Fitosanidad 14(3):181-183

³Mito, T. and T. Uesugi. 2004. Invasive alien species in Japan: the status quo and the new regulation for prevention of their adverse effects. Global Environmental Research 8(2): 171-191. http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CC0QFjAB&url=http%3A%2F%2Fwww.airies.or.jp%2Fattach.php%2F6a6f75726e616c5f30382d32656e67%2Fsave%2F0%2F0%2F08_2-08.pdf&ei=YN9vUtC9IsqDiQLx2IDACg&usg=AFQjCNF_T2F8hHiHRH1hX2i0gqYjsDcT1g&bvm=bv.55123115,d.cGE

⁴Bromelcairns. 2009 #2 and 2010#3. Bimonthly Newsletter of Cairns Bromeliad Society, Inc. P.O. Box 28 Cairns, Queensland, 4870 Australia. http://www.bromeliadsdownunder.com/wp-content/uploads/2012/03/Bromelcairns-2009-Issue-4.pdf

http://www.bromeliadsdownunder.com/wp-content/uploads/2012/02/Bromelcairns-2010-Issue-3.pdf

⁵Miller, D.R., G.L. Miller, G.S. Hodges, and J.A. Davidson. 2005. Introduced scale insects (Hemiptera: Coccoidea) of the United States and their impact on U.S. Agriculture. Proceedings of the Entomological Society of Washington 107(1): 123-158. http://www.sel.barc.usda.gov/coccoidea/millermihoda2005.pdf

⁶Illawarra Bromeliad Society Inc. Club News. October 2012. 92 Brighton Street, Bundeena, NSW 2230 http://www.bromeliad.org.au/news/Ill1012.htm

⁷Stephens, J.A. 1965. Some thoughts on bromeliads. The Bromeliad Society Bulletin. Vol. XV(5). http://journal.bsi.org/V15/5/

⁸http://www.forestryimages.org/browse/detail.cfm?imgnum=5117097

⁹ USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD). https://pcit.aphis.usda.gov/pcit/