(Comstock, 1881)
Diagnosis
In life, scale cover of adult female 1.0-2.0 mm long, circular to somewhat elongate, convex, grey to white with yellow-brown central or subcentral exuviae HEMRAL5.jpg and HEMRAL1.jpg and HEMRAL3.jpg . Ventral scale often well developed. Gill, 1997, said males were not known in California but they must occur elsewhere, as Davidson and Miller, 1990, described the male scale cover as similar to that of female but smaller and more oval, with yellow subterminal exuviae. Exposed body of adult female bright yellow.
Slide-mounted adult female 1.0-1.5 mm long, membranous and pyriform HEMRAS.jpg . Pygidium with median lobes large and closely set; second and third lobes often unsclerotized, very small, third lobes reduced to small points; perivulvar pores absent; a large anal opening situated near the posterior margin of the pygidium (less than 2.3 times its length from base of median lobes) HEMRAP.jpg ; paraphyses shorter than the lobes, present only on the margin between the third lobes; only 1 or 2 submedian macroducts present on each side of abdominal segment 5; segment 4 without submarginal macroducts HEMRAMG.jpg .
Host range
Hemiberlesia rapax is a highly polyphagous species that has been recorded from hosts belonging to 117 genera in 60 plant families; it seems to prefer woody ornamental plants (Davidson and Miller, 1990). Hosts include species of: Acacia, Actinidia spp., Adesmia, Albizia, Aleurites spp., Allophyllus, Amomyrtus, Aristotelia, Baccharis spp., Beilschmiedia, Buxus, Camellia, Carya illinoinensis, Cassia, Castela, Cercis, Citrus spp., Condalia, Copernicia, Coprosma, Corylus, Cupania, Cydonia, Drimys, Elaeagnus, Erigeron, Eriobotrya, Eucalyptus, Euonymus, Eupatorium, Fagara, Ficus spp., Fuchsia, Gleditsia, Heterothalamus, Hexachlamys, Ilex, Labiatae, Larrea, Laurus nobilis, Liriodendron, Lonicera, Magnolia, Malus pumila, Malus sylvestris, Mangifera indica, Manihot, Melia, Merostachys, Muehlenbeckia, Musa spp., Myosporum, Myrciaria, Nectandra, Olea europaea, Osmanthus, Persea americana, Peumus, Phoebe, Piper, Poncirus, Prosopis, Prunus spp., Psidium guajava, Pyrus communis, Rhamnus, Robinia, Salix, Sapium, Senna, Sesbania, Sida, Solanaceae, Solanum, Tecoma stans, Trichogonia, Vaccinium, Vernonia, Vitillaria and Vitis vinifera.
Affected plant stages: vegetative growing, flowering, fruiting and post-harvest stages
Affected plant parts: on the bark of branches and twigs HEMRAL4.jpg ; on leaves and fruit to a lesser extent
Biology and ecology
Reproduction in H. rapax is believed to be either uniparental or biparental depending upon geographical region; uniparental populations were mentioned by Schmutterer, 1952, and Nur, 1971. Gill, 1997, reported H. rapax to be parthenogenetic and ovoviviparous in California, USA, with two or more generations annually. However, Merrill, 1953; Miller, 1985; and Davidson and Miller, 1990, described both males and females, indicating that some populations reproduce sexually. The number of generations depends on climatic conditions (Kosztarab, 1996).
Each female deposits a cluster of 30-50 yellow eggs underneath her scale cover. There may be two or more generations per year outdoors; under glass, reproduction is continuous and generations overlap (Schuh and Mote, 1948; Stimmel, 1987). Two generations per year were recorded in New Zealand by Dale, 1981; Blank et al., 1996, determined the time of these two population peaks for the various stages, based on degree days.
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
Hemiberlesia rapax is most often found on the bark of the trunk and limbs of its host, but in heavy infestations it spreads to the axils of leaves and onto the fruit. Infestation by H. rapax often causes leaf yellowing, development of necrotic patches and premature leaf drop; dieback of stems and growing points; and fruit discolouration and premature drop.
Economic impact
Hemiberlesia rapax is a major pest of both fruit and woody ornamental plants, primarily in the tropical and subtropical regions (Davidson and Miller, 1990). Because scale insects are important quarantine pests, export of fruit like kiwifruit and blueberries can be inhibited if infested (Tomkins and Koller, 1985; Blank et al., 1996). Of the kiwifruit rejected for export from New Zealand, 56% had a single scale while mature scales were primarily responsible for rejection of fruit (Blank et al., 1992). Hemiberlesia rapax is a frequent pest of pecan in Florida (Dekle, 1976), and Gill, 1997, reported it to be an occasional pest of ornamentals in California. Charles and Henderson, submitted, record it as a pest on economically important plants in New Zealand, and that it occurs on native plants there also. It is economically important in Argentina (Crouzel, 1973); on several hosts in Brazil, and has become important on kiwifruit (Actinidia chinensis) in Chile (Claps et al., 2001a). Argyriou, 1990, lists H. rapax as seriously damaging olive in Chile. It is a known pest of tea in Sri Lanka (Muraleedharan, 1983), infesting the stem, branches and leaves, making the bushes weak and unproductive; persistent attacks may kill pruned bushes and seedlings (Das and Ganguli, 1961; Chua and Wood, 1990). Danzig and Pellizzari, 1998, describe H. rapax as a dangerous pest in the Palaearctic region, and Foldi, 2001, lists it as of economic importance in France. It is an occasional pest of Citrus. Although this species has been present in Italy for several years, it is considered of little economic importance there (Bianchi et al., 1994). Hemiberlesia rapax is often found infesting plants in glasshouses but it seldom becomes a major pest under glass.
Detection and inspection methods
Bark of the trunk and limbs, and leaf axils, should be closely inspected for the scale covers in strong light. Sticky traps are often used in New Zealand kiwifruit orchards to monitor the aerial dispersal of crawlers (Blank et al., 1987).
Phytosanitary protection
Hemiberlesia rapax is mentioned on quarantine lists (Burger and Ulenberg, 1990).
Natural enemies
Parasitoids:
- Aphytis proclia in Italy
- Encarsia citrina, attacking: nymphs, in Europe, USA, New Zealand
- Signiphora flavella, attacking: nymphs, adults, in New Zealand
- Signiphora merceti, attacking: nymphs, adults, in Europe, USA, South Africa, New Zealand
Predators:
- Hemisarcoptes malus, attacking: eggs, nymphs, adults, in Introduced: New Zealand
Distribution
See Hemiberlesia rapax distribution.
It is difficult to distinguish this species from H. diffinis and H. lataniae in the field; H. palmae is also similar (Gill, 1997). Dekle, 1976 remarked that H. rapax was often confused with Diaspidiotus ancylus, but can be distinguished by its darker exuviae. Hemiberlesia rapax resembles Aspidiotus nerii in life but its scale cover is not as flat as that of A. nerii (Gill, 1997). Microscopic examination of slide-mounted females is necessary to authoritatively distinguish between the species.
Hemiberlesia diffinis (Newstead) (diffinis scale) HEMDIFS.jpg could be misidentified as H. rapax, but differs in having the second and third lobes acute and sclerotized, and the plates lateral to the third lobes large and deeply fringed HEMDIFP.jpg. In contrast, H. rapax has the second and third lobes represented by unscerotized points, and the plates lateral to the third lobes are simple HEMRAP.jpg. Hemiberlesia diffinis is a polyphagous, tropical species known from Canada, USA (Alabama, Arkansas, District of Colombia, Florida, Georgia, Illinois, Lansas, Louisiana, Maryland, Missouri, Mississippi, North Carolina, New Jersey, New York, Ohio, South Carolina, Tennessee, Texas, Virginia), Argentina (Corrientes, Misiones, Salta, Santa Fe, Tucumán), Brazil (Rio Grande do Sul), Colombia, Costa Rica, Curaçao, Dominica, Ecuador, El Salvador, Guatemala, Guyana, Jamaica, Mexico, Nicaragua, Panama, Peru, St Kitts and Trinidad (Miller and Davidson, 1998; Nakahara, 1982). It is probably native to North America (Dekle, 1976). Hemiberlesia diffinis is often found on the bark of trunk and branches of woody hosts such as species of Aleurites, Annona, Aspidosperma, Bursera, Caesalpinia, Cassia, Casuarina, Citrus, Cocos, Couroupita, Dracaena, Erythrina, Eucalyptus, Hevea, Hibiscus, Jatropha, Machaerium, Malus sylvestris, Mammea, Manihot, Mimosa, Musa, Oncidium, Persea, Prunus, Psidium guajava, Punica, Pyrus communis, Spondias, Theobroma, Ulmus and Vitis vinifera (Dekle, 1976; Kosztarab, 1996; Miller, 1996; Miller and Davidson, 1998; Claps et al., 2001a; Kondo, 2001; The Natural History Museum collection, London, UK). Stoetzel and Davidson, 1974, studied the immature stages and natural enemies of H. diffinis. There is one generation per year in Maryland, and overwintering is as second instars; adult males are winged (Stoetzel and Davidson, 1974). This species is not of economic importance in Florida (Dekle, 1976). External appearance of females HEMDIFL1.jpg ; habit sketch HEMDIFL.jpg
Hemiberlesia neodiffinis Miller and Davidson could be misidentified as H. rapax, but differs in having the second and third lobes acute and sclerotized, and the plates lateral to the third lobes fringed. In contrast, H. rapax has the second and third lobes represented by unscerotized points, and the plates lateral to the third lobes are simple HEMRAP.jpg. Hemiberlesia neodiffinis is a temperate species known from USA (Alabama, Arkansas, District of Colombia, Florida, Georgia, Illinois, Kansas, Louisiana, Maryland, Missouri, Mississippi, North Carolina, New Jersey, New York, Ohio, South Carolina, Tennessee, Texas, Virginia) and northern Mexico on species of Carya, Celtis, Cinnamomum, Ficus, Fraxinus, Juglans, Liriodendron, Magnolia, Nerium, Persea, Phorodendron, Pterocarya, Quercus, Salix, Spondias, Syringa, Tilia, Ulmus (Nakahara, 1982; Miller and Davidson, 1998).
Hemiberlesia neodiffinis Miller and Davidson and H. diffinis (above) can be separated as follows: H. diffinis has a macroduct present between the median lobes and obviously enlarged plates lateral to each third lobe, each of these plates containing 2 or 3 associated microducts HEMDIFP.jpg. In contrast, H. neodiffinis has no macroduct between the median lones, normal sized plates lateral to each third lobe, and each of these plates contains only one associated microduct (Miller and Davidson, 1998).
Comments
Hemiberlesia rapax is thought to be native to Europe (Gill, 1997). Originally described from North America, this species is now widespread throughout the tropics and subtropics (Davidson and Miller, 1990) and some temperate areas (Williams and Watson, 1988). In northern countries it is found under glass (Danzig and Pellizzari, 1998).
Europe
Cyprus: present, no further details (Danzig and Pellizzari, 1998)
Former USSR
Armenia: present, no further details (Nakahara, 1982)
Georgia: present, no further details (Nakahara, 1982; Danzig and Pellizzari, 1998)
Kazakhstan: present, no further details (CABIIE, 1987)
Russian Federation: present, no further details (Kolodochka, 1983)
Former Yugoslavia: present, no further details (Danzig and Pellizzari, 1998)
France: present, no further details (Danzig and Pellizzari, 1998; Foldi, 2001)
Corsica: The Natural History Museum collection, London, UK
Greece: present, no further details (Danzig and Pellizzari, 1998)
Italy: present, no further details (Bianchi et al., 1994; Longo et al., 1995; Danzig and Pellizzari, 1998)
Sardinia: present, no further details (Longo et al., 1995)
Sicily: present, no further details (Longo et al., 1995)
Luxemburg: present, no further details (Danzig and Pellizzari, 1998)
Portugal: present, no further details (Merrill, 1953; Danzig and Pellizzari, 1998)
Azores: present, no further details (Nakahara, 1982)
Madeira: present, no further details (Nakahara, 1982)
Romania: present, no further details (Danzig and Pellizzari, 1998)
Spain: fairly widespread (Amparo Blay Golcoechea, 1993; Danzig and Pellizzari, 1998)
Canary Is: present, no further details (Amparo Blay Golcoechea, 1993)
Asia
China: present, no further details (Nakahara, 1982; Danzig and Pellizzari, 1998)
Anhui: present, no further details (CABIIE, 1987)
Fujian: present, no further details (CABIIE, 1987)
Guangdong: present, no further details (CABIIE, 1987)
Jiangsu: present, no further details (Tao, 1999)
Sichuan: present, no further details (CABIIE, 1987)
Yunnan: present, no further details (Tao, 1999)
Zhejiang: present, no further details (CABIIE, 1987)
India: present, no further details (Nakahara, 1982; Devnath, 1985; Devnath, 1988)
Arunachal Pradesh: present, no further details (Asham Borang, 1996)
Assam: The Natural History Museum collection, London, UK
Karnataka: present, no further details (CABIIE, 1987)
Delhi: present, no further details (CABIIE, 1987)
Maharashtra: present, no further details (CABIIE, 1987)
Maghalaya: present, no further details (CABIIE, 1987)
Tamil Nadu: present, no further details (CABIIE, 1987)
West Bengal: present, no further details (Blank et al., 1987)
Iran: present, no further details (Seghatoleslami, 1977; Danzig and Pellizzari, 1998)
Israel: present, no further details (Nakahara, 1982; Danzig and Pellizzari, 1998)
Japan: present (Kawai, 1980; Nakahara, 1982; Kosztarab, 1996)
Honshu: present, no further details (CABIIE, 1987)
Kyushu: present, no further details (CABIIE, 1987)
Okinawa: present, no further details (Nakahara, 1982)
Malaysia: present, no further details (APPPC, 1987)
Pakistan: present, no further details (CABIIE, 1987)
Philippines: present, no further details (Nakahara, 1982)
Sri Lanka: present, no further details (Nakahara, 1982)
Syria: present, no further details (Nakahara, 1982; Danzig and Pellizzari, 1998)
Taiwan: present, no further details (Takagi, 1969; Tao, 1999)
Turkey: present, no further details (Danzig and Pellizzari, 1998)
Africa
Algeria: present, no further details (Nakahara, 1982; Danzig and Pellizzari, 1998)
Egypt: present, no further details (Nakahara, 1982; Danzig and Pellizzari, 1998)
Eritrea: The Natural History Museum collection, London, UK
Kenya: present, no further details (Nakahara, 1982)
Madagascar: present, no further details (Mamet, 1954; Nakahara, 1982)
Malawi: present, no further details (Nakahara, 1982)
Mauritius: present, no further details (Williams and Williams, 1988)
Morocco: present, no further details (Nakahara, 1982; Danzig and Pellizzari, 1998)
Réunion: present, no further details (Williams and Williams, 1988)
Seychelles: present, no further details (CABIIE, 1987)
South Africa: present, no further details (Merrill, 1953; Nakahara, 1982)
Tanzania: present, no further details (Nakahara, 1982)
Tunisia: present, no further details (CABIIE, 1987)
Zambia: The Natural History Museum collection, London, UK
Zimbabwe: present, no further details (Merrill, 1953; Nakahara, 1982)
Western Hemisphere
Argentina: very frequent (Claps et al., 2001a)
Buenos Aires: present, no further details (Claps et al., 2001a)
Catamarca: present, no further details (Claps et al., 2001a)
Córdoba: present, no further details (Claps et al., 2001a)
Corrientes: present, no further details (Claps et al., 2001a)
Entre Rios: present, no further details (Claps et al., 2001a)
Jujuy: present, no further details (CABIIE, 1987)
Mendoza: present, no further details (Claps et al., 2001a)
Rio Negro: present, no further details (Claps et al., 2001a)
Salta: present, no further details (Claps et al., 2001a)
Tucumán: present, no further details (Claps et al., 2001a)
Barbados: present, no further details (Schotman, 1989)
Bermuda: present (Hodgson and Hilburn, 1991)
Bolivia: present, no further details (Squire, 1972a; Nakahara, 1982)
Brazil: widespread (Claps et al., 2001a)
Bahia: present, no further details (CABIIE, 1987)
Guanabara: present, no further details (Silva et al., 1968)
Minas Gerais: present, no further details (Claps et al., 2001a)
Paraíba: present, no further details (Claps et al., 2001a)
Rio de Janeiro: present, no further details (Claps et al., 2001a)
Rio Grande do Sul: present, no further details (Claps et al., 2001a)
Sao Paulo: present, no further details (Claps et al., 2001a)
Chile: very frequent (Claps et al., 2001a)
Aisén: present, no further details (Claps et al., 2001a)
Antofagasta: present, no further details (Claps et al., 2001a)
Atacama: present, no further details (Claps et al., 2001a)
Biobío: present, no further details (Claps et al., 2001a)
Coquimbo: present, no further details (Claps et al., 2001a)
Isla J. Fernández: present, no further details (Claps et al., 2001a)
La Araucanía: present, no further details (Claps et al., 2001a)
Los Lagos: present, no further details (Claps et al., 2001a)
Maule: present, no further details (Claps et al., 2001a)
O'Higgins: present, no further details (Claps et al., 2001a)
Santiago: present, no further details (Claps et al., 2001a)
Tarapacá: present, no further details (Claps et al., 2001a)
Valparaiso: present, no further details (Claps et al., 2001a)
Colombia: present, no further details (Nakahara, 1982; Schotman, 1989)
Costa Rica: present, no further details (Nakahara, 1982; Schotman, 1989)
Cuba: present, no further details (Nakahara, 1982; Schotman, 1989)
Ecuador: present, no further details (Nakahara, 1982; Schotman, 1989)
Guatemala: present, no further details (Nakahara, 1982; Schotman, 1989)
Guyana: present, no further details (Nakahara, 1982; Schotman, 1989)
Honduras: present, no further details (Hawksworth and Wicker, 1973)
Jamaica: present, no further details (Schotman, 1989)
Mexico: present, no further details (Schotman, 1989; Salaza-Torres and Solis-Aguilar, 1990; Miller, 1996)
Peru: present, no further details (Nakahara, 1982; Schotman, 1989)
Puerto Rico: present, no further details (Nakahara, 1982; Schotman, 1989)
Uruguay: present, no further details (Nakahara, 1982)
Trinidad: present, no further details (Schotman, 1989)
USA
Alabama: present, no further details (Nakahara, 1982)
California: widespread at low altitudes (Gill, 1997)
Connecticut: present, no further details (Nakahara, 1982)
Delaware: present, no further details (Nakahara, 1982)
District of Colombia: present, no further details (Nakahara, 1982; Davidson and Miller, 1990)
Florida: present, no further details (Nakahara, 1982)
Georgia: present, no further details (Nakahara, 1982)
Hawaii: present on Oahu, Maui and Kauai (Heu, 2002)
Idaho: present, no further details (Nakahara, 1982)
Illinois: present, no further details (Nakahara, 1982; Kosztarab, 1996)
Indiana: present, no further details (Nakahara, 1982; Kosztarab, 1996)
Louisiana: present, no further details (Nakahara, 1982)
Maine: present, no further details (Nakahara, 1982)
Maryland: present, no further details (Nakahara, 1982; Kosztarab, 1996)
Michigan: present, no further details (Nakahara, 1982; Kosztarab, 1996)
Mississippi: present, no further details (Nakahara, 1982)
Missouri: present, no further details (Nakahara, 1982)
New Jersey: present, no further details (Nakahara, 1982; Kosztarab, 1996)
New York: present, no further details (Nakahara, 1982; Kosztarab, 1996)
North Carolina: present, no further details (Nakahara, 1982)
Ohio: present, no further details (Nakahara, 1982; Kosztarab, 1996)
Oregon: present, no further details (Nakahara, 1982)
Pennsylvania: present, no further details (Stimmel, 1987; Kosztarab, 1996)
Rhode Island: present, no further details (Nakahara, 1982)
South Carolina: present, no further details (Nakahara, 1982)
Tennessee: present, no further details (Lambdin and Watson, 1980; Nakahara, 1982)
Texas: present, no further details (Nakahara, 1982)
Virginia: present, no further details (Nakahara, 1982; Kosztarab, 1996)
Washington: present, no further details (CABIIE, 1987)
West Virginia: present, no further details (Nakahara, 1982)
Uruguay: present, no further details (Schotman, 1989)
Oceania
Australia: present, no further details (Nakahara, 1982)
Queensland: present, no further details (CSIRO, 2001)
South Australia: present, no further details (CSIRO, 2001)
Tasmania: present, no further details (CSIRO, 2001)
Victoria: present, no further details (CSIRO, 2001)
Bonin Is: present, no further details (Nakahara, 1982)
Christmas I.: present, no further details (Nakahara, 1982)
Kiribati: present on Flint (Doanne and Hadden, 1909)
New Caledonia: present, no further details (Williams and Watson, 1988)
New Zealand: present, no further details (Williams and Watson, 1988; Hill et al., 1993; Charles and Henderson, submitted)
Ogasawara-shoto: present, no further details (CABIIE, 1987)
Papua New Guinea: The Natural History Museum collection, London, UK
Tahiti: present, no further details (CABIIE, 1987)