Invasive : Risks and Pathways Project SCALE

UPDATED: APRIL 2020

Invasive insects are a huge biosecurity challenge. We profile some of the most harmful invaders overseas to show why we must keep them out of Australia.

Species Cycad aulacaspis scale / . Also known as Asian cycad scale. Main impacts Decimates wild cycad populations, kills cultivated . Native range Thailand. Invasive range China, Taiwan, Singapore, Indonesia, , United States, Caribbean Islands, Mexico, France, Ivory Coast1,2. Detected in New Zealand in 2004, but eradicated.2

Main pathways of global spread As a contaminant of traded nursery material (cycads and cycad foliage).3 WHAT TO LOOK OUT FOR The adult female cycad aulacaspis scale has a white cover (scale), 1.2–1.6 mm long, ENVIRONMENTAL variable in shape and sometimes translucent enough to see the orange insect with its IMPACTS OVERSEAS orange eggs beneath. The scale of the male is white and elongate, 0.5–0.6 mm long. Photo: Jeffrey W. Lotz, Florida Department of Agriculture and Consumer Services, The cycad aulacaspis scale has decimated Bugwood.org | CC BY 3.0 cycads on Guam since it appeared there in 2003. The affected , micronesica, was once the most common cause cycad extinctions around the world, Taiwan, 100,000 cycads were destroyed tree on Guam, but was listed by the IUCN 7 including in India10 and Indonesia11. The by an outbreak of the scale . It is difficult as endangered in 2006 following attacks continuous removal of sap by the to control in cultivation because of high by three insect pests, of which this scale scale depletes cycads of carbohydrates4,9. fecundity, and because it infests roots, 4 is the worst . A reference population Highly infested cycads become almost where it escapes insecticides. declined from 686 prior to the completely coated with a white crust (as cycad reaching it to 87 individuals just if covered in snow) made up of the scales 5 three years later . In 2010 a Taiwanese (protective waxy coverings) of live and AUSTRALIAN cycad, , was also listed dead insects8. Once established, the scale CONCERNS by the IUCN as endangered because of 9 is ‘unusually difficult’ to control . The broad host range of the cycad this scale6, and scientists have written of aulacaspis scale suggests that all of its ‘imminent extinction’7. After the scale Australia’s cycad species could be at appeared in Florida in 1996, cycads in a HUMAN AND risk. Australia has a very diverse, mostly botanical garden suffered attacks that ECONOMIC IMPACTS threatened the survival of several rare and endemic, cycad flora, with many species OVERSEAS inherently vulnerable to extinction due to in its collection8. Cycads are important ornamental plants, their small populations. They include six The cycad aulacaspis scale attacks species and unsightly infections in gardens and cycads listed as nationally endangered in all three cycad families, and has been deaths in nurseries are problems for the (two Cycas and two Macrozamia species) recorded on plants from eight of ten gardening industry. In one of the world’s and eight listed as vulnerable (three cycad genera1,9. There are concerns it will leading exporters of cycads, a nursery in Cycas, fiveMacrozamia )12. Additional

INVASION WATCH: Cycad aulacaspis scale Cycad scale on sago palm leaf. Photo: Scot Nelson species are listed as threatened in climate change scenarios and the implications Species profile: Aulacaspis yasumatsui. Invasive Queensland and New South Wales. for management. PeerJ. 6: e4832. Species Specialist Group, IUCN. Retrieved The cycad aulacaspis scale could cause 2. Germain JF, Hodges GS (2007): First from http://www.iucngisd.org/gisd/species. extinctions even without killing plants report of Aulacaspis yasumatsui (: php?sc=814. if it sends populations into permanent ) in Africa (Ivory Coast), and update 10. Muniappan R, Viraktamath CA (2006): The decline by reducing their seed output on distribution. Florida Entomologist. 90: Asian cycad scale Aulocaspis yasumatsui, a and seedling vigour. In Florida, one of the 755–756. threat to native cycads in India. Current Science. 91: 868–870. cultivated cycads attacked by the scale is 3. Invasive insects: risks and pathways. an Australian species (Cycas media)8. Unpublished data (2019): Monash University 11. Muniappan R, Watson GW, Evans GA, Rauf and Invasive Species Council. A, Von Ellenrieder N (2012): Cycad aulacaspis The scale has wide climatic tolerances, 4. Marler TE, Cascasan ANJ (2018): scale, a newly introduced insect pest in judging by its success in locations as Carbohydrate depletion during lethal Indonesia. HAYATI Journal of Biosciences. 19: varied as Singapore, France, Taiwan and infestation of Aulacaspis yasumatsui on Cycas 110–114. Texas. Climatic modelling indicates that revoluta. International Journal of Plant Sciences. 12. Department of the Environment and Energy much of Australia, including in eastern 179: 497–504. (n.d.): Species Profile and Threats Database. Queensland, which is rich in cycad 5. Marler T, Haynes J, Lindstrom A (2010): EPBC Act list of threatened flora. Australian species, is suitable1. Cycas micronesica. The IUCN Red List of Government. Retrieved from http://www. Threatened Species. International Union for the environment.gov.au/cgi-bin/sprat/public/ Australia allows the importation of Conservation of Nature. Retrieved from http:// publicthreatenedlist.pl?wanted=flora. cycad foliage for the florist trade from dx.doi.org/10.2305/IUCN.UK.2010-3.RLTS. 13. Interim Inspector-General of Biosecurity all countries, subject to fumigation13. In T61316A12462113.e. (2015): Effectiveness of biosecurity controls 2015 the Interim Inspector-General of 6. Haynes J (2010): Cycas taitungensis. for imported fresh cut flowers. Audit Report. Biosecurity examined the effectiveness The IUCN Red List of Threatened Species. Australian Government. of biosecurity for imported flowers and International Union for the Conservation foliage and found that some staff weren’t of Nature. Retrieved from http://dx.doi. inspecting imports at the required rate, org/10.2305/IUCN.UK.2010-3.RLTS. ABOUT THIS PROJECT some insects were surviving fumigation, T42067A10642224.en. The Invasive Insects: Risks and Pathways Project is a partnership 7. Ravuiwasa KT, Tan C-W, Bezirganoglu I, and some flower boxes had ventilation between Monash University and the Invasive holes that pests could escape through Hwang S-Y (2012): Temperature-dependent Species Council. To find out more visit before treatment13. In France the scale demography of Aulacaspis yasumatsui invasives.org.au/risks-and-pathways. was detected on cycad foliage imported (Hemiptera: Diaspididae). Journal of Economic from Africa2. Entomology. 105: 1581–1590. 8. Howard FW, Hamon A, Mclaughlin M, Weissling T, Yang S (1999): Aulacaspis SOURCES yasumatsui (Hemiptera: : 1. Wei J, Zhao Q, Zhao W, Zhang H (2018): Diaspididae), a pest of cycads Predicting the potential distributions of the recently introduced into Florida. Florida invasive cycad scale Aulacaspis yasumatsui Entomologist. 82: 14–27. (Hemiptera: Diaspididae) under different 9. Global Invasive Species Database (2010):

INVASION WATCH: Cycad aulacaspis scale