(Cockerell, 1901)
Diagnosis
Scale cover of adult female in life often concealed under host's epidermis, circular, grey and convex, about 2 mm across, with subcentral yellow-orange or bronze exuviae DUPCLAL1.jpg . Male not known (Dekle, 1976).
Body of slide-mounted adult female with cuticle often slightly sclerotized, with constriction between prothorax and mesothorax, and lateral lobes developed on thoracic and free abdominal segments DUPCLS.jpg . Dorsum of pygidium with areolate sclerostized pattern present; pygidium with two pairs of large, elongate paraphyses, each paraphysis with an anterior circular knob that is more or less detached from the paraphysis DUPCLP1.jpg .
Host range
Duplaspis claviger has been recorded from hosts belonging to 40 genera in 24 plant families (Davidson and Miller, 1990). Favoured hosts in Florida are Camellia, Ligustrum and Viburnum (Dekle, 1976). Hosts include species of: Annona, Artocarpus, Averrhoa, Buxus, Callicarpa, Callistemon, Camellia, Carya, Cestrum, Citrus, Cornus, Dodonaea, Duranta, Eugenia, Eurya, Ficus, Fortunella, Gardenia, Hibiscus, Ilex, Inga, Jasminum, Lagerstroemia, Ligustrum, Macadamia tetraphylla, Mangifera indica, Melaleuca, Myrciaria, Myrica, Osmanthus, Prunus, Psidium, Punica granatum, Pyracantha, Quercus, Rhododendron, Rhus, Rosa, Santalum, Schinus, Severinia, Swietenia, Syzygium, Tibouchina, Urena, Vaccinium and Viburnum.
Affected plant stages: vegetative growing, flowering and fruiting stages
Affected plant parts: on twigs and branches, under the epidermis DUPCLAL1.jpg
Biology and ecology
There is no information available on the biology of D. claviger (Davidson and Miller, 1990); since no males have been observed, it may reproduce parthenogenetically. The sharp edges of the pygidial lobes are used to mine beneath the epidermis of the host during scale cover formation.
Crawlers are the primary dispersal stage and move to new areas of the plant or are dispersed by wind or animal contact. Mortality due to abiotic factors is high in this stage. Dispersal of sessile adults and eggs occurs through human transport of infested plant material.
Symptoms
Heavy infestations of Camellia in Florida cause considerable dieback of twigs and branches and limited new growth (Dekle, 1976).
Economic impact
Heavy infestations of Camellia in Florida cause considerable dieback of twigs and branches and limited new growth (Dekle, 1976). Such damage may be of significance to the ornamental plant industry.
Detection and inspection methods
Closely examine the bark of twigs and branches of the hosts listed above, looking for slight, greyish swellings that may have a trace of subcentral yellow-orange or bronze exuviae showing. The scales are very cryptic and difficult to see on fresh material, but sometimes become more obvious if the plant tissue is allowed to dry out for a few days.
Natural enemies
The natural enemies of D. claviger have not been studied.
Distribution
See Duplaspidiotus claviger distribution.
Microscopic examination of slide-mounted adult females is required for authoritative identification to species.
Foldi, 1989, lists Duplaspidiotus fossor (Newstead) as a species damaging to grapevines in South America. In the Picture Key, D. fossor keys out as close to D. claviger, but the identification is obvously incorrect. In D. fossor there are no perivulvar pores and the paraphyses lack the anterior circular knobs, whereas these characters are present in D. claviger. Duplaspidiotus fossor has 5 pairs of elongate paraphyses, whereas D. tesseratus (below) has only two pairs. Duplaspidiotus fossor is known from Mexico, Barbados, Guyana, Puerto Rico and Brazil (Bahia, Pernambuco, Rio Grande do Sul, Santa Caterina) under the outer bark of Ficus and Vitis vinifera (USDA, 1978; Foldi, 1989; Miller, 1996; Claps et al., 2001a; collection of The Natural History Museum, London, UK).
Duplaspidiotus tesseratus (Grandpré and Charmoy) could be misidentified as D. claviger, but differs in lacking the perivulvar pores that are present in D. claviger DUPCLP1.jpg. Duplaspidiotus tesseratus is a polyphagous tropical species that has been recorded from USA (Florida, Hawaii), the Caribbean Islands (including Barbados, Curaçao, Jamaica), Bahamas, Brazil (Pernambuco, Rio de Janeiro, Rio Grande do Sul, Santa Caterina, Sao Paulo), Colombia, Ecuador, El Salvador, Guatemala, Guyana, Mexico, Nicaragua, Panama, Venezuela, Ghana, Kenya, Liberia, Mauritus, Mozambique, Rodrigues, South Africa, Uganda, Zimbabwe, Yemen, India (Karnataka, Madras, Maharashtra, Tamil Nadu), Indonesia (Java), Pakistan and Sri Lanka on the bark of species of Acalypha, Allamanda, Averrhoa, Coffea, Leucaena and Vitis vinifera (Rao and Kumar, 1952; Silva et al., 1968; Nakahara, 1982; Williams and Williams, 1988; Foldi, 1989; Miller, 1996; Claps et al., 2001a; Kondo, 2001; The Natural History Museum collection, London, UK). Foldi, 1989, lists D. tesseratus as a species damaging to grapevines in South America. The species is mentioned on quarantine lists (Burger and Ulenberg, 1990). The following picture is of Duplaspidiotus ?tessellatus in Brazil (no specimens have been available to check the identity of the scale insect). DUPQTESL.jpg
Comments
Duplaspidiotus claviger is a tropical species of uncertain origin. It has not been recorded from Europe.
Asia
China: present, no further details (Nakahara, 1982; Danzig and Pellizzari, 1998)
Yunnan: present, no further details (Tao, 1999)
Indonesia: present, no further details (Nakahara, 1982)
Japan: present, cannot read any further details (Kawai, 1980; Tao, 1999)
Amami: present (1996 data from S. Kawai photograph)
South-East Asia: present, no further details (Danzig and Pellizzari, 1998)
Sri Lanka: present, no further details (Nakahara, 1982)
Taiwan: present, no further details (Tao, 1999)
Africa
Seychelles: present, no further details (Nakahara, 1982)
South Africa: present, no further details (Dekle and Kuitert, 1975; Nakahara, 1982)
Western Hemisphere
Panama: present, no further details (Dekle and Kuitert, 1975)
USA
Florida: present, no further details (Dekle and Kuitert, 1975; Davidson and Miller, 1990)
Hawaii: present, no further details (Davidson and Miller, 1990)
Oceania
Australia
New South Wales: present, no further details (CSIRO, 2001)
Cook Is: present (Williams and Watson, 1988)
Fiji: present (Williams and Watson, 1988)
South Mariana Is: present on Guam (Nakahara, 1982; Beardsley, 1966)
Niue: present (Williams and Watson, 1988)
Papua New Guinea: present (Williams and Watson, 1988)
Tahiti: present, no further details (Nakahara, 1982)
Western Samoa: present (Williams and Watson, 1988)