Pink wax scale Ceroplastes rubens

Fig. 1 Colony of pink wax scale on bay laurel (the white scales are a different species) © Keisotyo

Ceroplastes rubens Maskell (Hemiptera: Coccidae) is a soft scale insect, commonly known as the pink or red wax scale, that occurs widely in tropical and subtropical regions. It is broadly polyphagous and a serious pest of many tropical and subtropical crops and ornamental plants. Ceroplastes rubens was recently collected in the British Virgin Islands by Martin Hamilton (Royal Botanic Gardens, Kew, UK) feeding on native plants and it has the potential to spread to other United Kingdom Overseas Territories (UKOT) in the Caribbean.

Geographical distribution Ceroplastes rubens is suspected to be native to the Afrotropical region (Qin et al ., 1994) but now occurs widely in tropical and subtropical regions of the Americas, Africa, Asia, Australia and the Pacific. It also extends into neighbouring warm temperate areas. North America : USA. South America : Colombia. Caribbean : British Virgin Islands (UKOT); Guadeloupe; Haiti; Martinique; Puerto Rico & Vieques Island. Africa : Kenya; Reunion; Seychelles; South Africa; Tanzania; Zanzibar.

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Asia : China; Hong Kong; India; Indonesia; Japan; Malaysia; Maldives; Philippines; Ryukyu Islands; South Korea; Sri Lanka; Taiwan; Thailand; Vietnam. Australasian : Australia; Cook Islands; Fiji; French Polynesia; Guam; Hawaiian Islands; Kiribati; New Caledonia; Norfolk Island; Northern Mariana Islands; Palau; Papua New Guinea; Solomon Islands; Vanuatu; Western Samoa.

Host plants Ceroplastes rubens is extremely polyphagous, occurring on hundreds of plant species assigned to at least 80 families including many tropical and sub-tropical crops, and ornamental plants . It also feeds on several species of Pinus , including important forestry species. The following host list only includes host families and genera and further details are available from ScaleNet (www.sel.barc.usda.gov/scalenet/scalenet.htm). Acanthaceae : Strobilanthes . Aceraceae : Acer . Amaranthaceae : Celosia . Anacardiaceae : Anacardium , Mangifera , Rhus , Schinus . Annonaceae : Annona . Apocynaceae : Allamanda , Alyxia , Melodinus , Nerium , Plumeria , Thevetia . Aquifoliaceae : Ilex . Araceae : Aglaonema , Anthurium , Dieffenbachia , Epipremnum , Rhaphidophora , Syngonium , Zantedeschia . Araliaceae : Aralia , Brassaia , Dizygotheca , Fatsia , Hedera , Meryta , Philodendron , Polyscias , Schefflera . Araliceae : Philodendron . Arecaceae , Cocos , Monstera . Aspleniaceae : Asplenium . Asteraceae : Artemisia , Chrysanthemum , Fitchia , Gerbera , Helianthus . Berberidaceae : Nandina . Bischofiaceae : Bischofia . Bixaceae : Bixa . Blechnaceae : Blechnum . Buxaceae : Buxus microphylla . Campanulaceae : Siphonodon . Caprifoliaceae : Viburnum . Celastraceae : Celastrus , Elaeodendron , Euonymus . Clusiaceae : Calophyllum , Garcinia , Montrouziera . Cucurbitaceae: unidentified. Cunoniaceae : Weinmannia . Cycadaceae : Cycas . Davalliaceae : Arthropteris , Davallia . Dicksoniaceae : Cibotium . Ebenaceae : Diospyros . Elaeocarpaceae : Elaeocarpus . Ericaceae : Rhododendron . Euphorbiaceae : Euphorbia . Fabaceae : Acacia , Cytisus , Dioclea , Inocarpus , Palaquium , Spartium . Gleicheniaceae : Dicranopteris , Gleichenia . Heliconiaceae : Heliconia . Hernandiaceae : Hernandia .

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Hypoxidaceae : Curculigo , Molineria . Lauraceae : Cinnamomum , Cryptocarya , Laurus , Lindera , Machilus , Persea . Lecythidaceae : Barringtonia . Lomariopsidaceae : Elaphoglossum . Loranthaceae : Loranthus . Magnoliaceae : Illicium , Magnolia . Malvaceae : Hibiscus . Melastomataceae : Astronidium . Monimiaceae : Wilkiea . Moraceae : Artocarpus , Cudrania , Ficus , Morus . Musaceae : Musa . Myristicaceae : Myristica . Myrsinaceae : Ardisia , Myrsine , Rapanea . Myrtaceae : Agonis , Callistemon , Eucalyptus, Eugenia , Feijoa , Melaleuca , Metrosideros , Pimenta , Psidium , Rhodomyrtus , Syzygium . Nyctaginaceae : Bougainvillea . Oleaceae : Ligustrum , Olea . Oleandraceae : Nephrolepis . Orchidaceae : Grammatophyllum , Stanhopea . Peperomiaceae : Peperomia . Phyllanthaceae : Antidesma . Pinaceae : Pinus . Piperaceae : Macropiper , Piper . Pittosporaceae : Pittosporum . Poaceae : Tristania . Polygonaceae : Coccoloba . Polypodiaceae : Belvisia , Phymatodes , Platycerium , Polypodium . Pteridaceae : Acrostichum . Punicaceae : Punica granatum . Rhizophoraceae : Rhizophora . Rosaceae : Chaenomeles , Eriobotrya , Malus , Photinia , Prunus , Pyrus , Spiraea . Rubiaceae : Coffea , Gardenia , Gouldia , Ixora , Paederia , Psychotria , Randia , Straussia . Rutaceae : Citrus , Eremocitrus , Evodia , Flindersia , Pelea , Poncirus . Santalaceae : Exocarpos . Sapindaceae : Cupaniopsis , Dimocarpus , Euphoria , Litchi , Nephelium . Sapotaceae : Calocarpum , Pouteria . Schisandraceae : Kadsura . Sinopteridaceae : Aspidotis , Pellaea . Symplocaceae : Symplocos . Tamaricaceae : Tamarix . Taxaceae : Cephalotaxus , Podacarpus . Theaceae : Camellia , Cleyera , Eurya , Ternstroemia . Thymelaeaceae : Daphne . Ulmaceae : Celtis . Verbenaceae : Premna . Zingiberaceae : Alpinia purpurata , Zingiber officinale

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Fig. 2 Colony of pink wax scale in Australia © Fig. 3 Colony of pink wax scales on Ixora in the Fera Cook Islands © 2007 The Cook Islands Natural Heritage Trust

Fig. 4 Pink wax scale nymph in Australia © Fig. 5 Pink wax scale adult female from Robert Whyte, Thailand © Fera www.saveourwaterwaysnow.com.au

Fig. 6 Pink wax scale adult female on Aglaonema Fig. 7 Pink wax scale male cover on from Sri Lanka © Fera Aglaonema from Sri Lanka © Fera

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Description Adult females (Figs 1-4 and 6) are covered in a dense layer a watery wax which varies in colour from white (Fig. 6), cream (Fig. 2), pink (Fig. 4) to reddish (Fig. 1) to brownish. It is strongly convex, longer than wide, pentagonal, and with two conspicuous pairs of white bands that extend dorsally from the anterior margin and half-way along the body (the bands are most conspicuous in Figs 1, 4 and 5); female wax cover length 3.5 to 4.5 mm. Adult female pink wax scales can usually be recognised in life by the presence of these white bands, particularly by the anterior bands which often almost touch each other. The nymphs are pinkish in colour with distinct white wax blocks, and the immature males (Fig. 7) form a whitish translucent, elongate, oval scale. Wax scales ( Ceroplastes spp.) frequently occur in mixed populations (Fig. 1). Recently published keys for the identification of slide-mounted adult female C. rubens include: Mohammad & Moharum (2013); Fetykó & Kozár (2012); Hodgson & Peronti (2012); Hodson et al. (2009); and Hodges 2002.

Pest biology, dispersal and detection Adult and nymph C. rubens feed on the stems, twigs, and foliage, apparently preferring the upper leaf surface (most species of Coccidae prefer the lower surface). They are often attended by ants which feed on the sugary honeydew excreted by the scale insects. Ceroplastes rubens has one generation a year in China and two generations a year in Australia. The average number of eggs laid per female is about 300, although females have been recorded laying as many as 1,187 eggs. Females have four instars and males have five, although males (Fig. 7) are rarely recorded. The first nymphal instars or ‘crawlers’ show a preference for settling to feed on new (current year) growth. They have a relatively low natural dispersal potential and often settle to feed within a short distance of their parent. Some of the crawlers may be dispersed over longer distances by air currents or be transported by other animals. Dispersal is likely to occur more rapidly and over longer distances with the movement of infested plants in trade. Infestations of C. rubens are readily detected by the highly conspicuous wax covers (Figs 1-7), which protect the scales from attack by predators and from injury and desiccation. The scales are often highly visible as they occur on the upper surface of the leaf forming lines along the mid-vein. The foliage is contaminated with honeydew excreted by the scales, which serves as a medium for the growth of sooty moulds. The scales and the mould can disfigure ornamental plants. The scales may also be detected by the presence of ants, and less frequently wasps and flies, which feed on the honeydew excreted by the insects.

Economic importance and damage Ceroplastes rubens is a widespread pest of citrus, coffee, tea, cinnamon, mango, avocado and litchi. It is a major pest of citrus in Australia, Hawaii, Korea, China and Japan. Economic damage is caused directly through phloem feeding and indirectly through the promotion of sooty mould growth on the excreted honeydew, which lowers the market value of fresh fruit and can reduce photosynthetic efficiency and gas exchange, causing reduced growth. Large populations cause necrosis of the foliage, leaf loss, die back, and death of susceptible plants. It is a regulated pest in some countries where it has not already established.

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Selected references Fetykó, K. & Kozár, F. 2012. Records of Ceroplastes Gray 1828 in Europe, with an identification key to species in the Palaearctic Region. Bulletin of Insectology 65 (2): 291-295. Hodges, G.S. 2002. A new species of Ceroplastes from Florida (Hemiptera: Coccoidea: Coccidae). Insecta Mundi 16 (4): 205-208. Hodgson, C.J. & Peronti, A.L.B.G. 2012. A revision of the wax scale insects (Hemiptera: Sternorrhyncha: Coccoidea: Ceroplastinae) of the Afrotropical Region. Zootaxa 3372 : 1–265 Hodgson, C.J., Williams, D.J. & Giliomee, J.H. 2009. The identity of the wax scale insect, Ceroplastes myricae (Linnaeus) (Sternorrhyncha: Coccoidea: Coccidae), and a key to the wax scales recorded from South Africa. African Entomology 17 (1): 95-105. Mohammad, Z.K. & Moharum, F.A. 2013. Key to the species of family Coccidae in Egypt (Hemiptera: Coccoidea: Coccidae). Egyptian Academic Journal of Biological Science 6 (2): 145–158. Qin, T.K., Gullan, P.J., Beattie, G.A.C., Trueman, J.W.H., Cranston, P.S., Fletcher, M.J. & Sands, D.P.A. 1994. The current distribution and geographical origin of the scale insect pest Ceroplastes sinensis (Hemiptera: Coccidae). Bulletin of Entomological Research 84 : 541-549.

Author: Chris Malumphy Address: The Food and Environment Research Agency, Sand Hutton, York, YO41 1LZ, UK. Email: [email protected] Date: 25/11/2014 Version 1

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