| Picture | Title | Caption | Copyright |
|---|---|---|---|
| Symptoms on leaves | C. aonidum is a leaf-infesting species. The scales appear as circular dark spots. | Clive Lau | |
| Symptoms on fruit | In high-density infestations C. aonidium may spread to fruits, stems and trunks. | Clive Lau |
Datasheet
Chrysomphalus aonidum (circular scale)
Index
- Pictures
- Identity
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Description
- Distribution
- Distribution Table
- Risk of Introduction
- Hosts/Species Affected
- Host Plants and Other Plants Affected
- Growth Stages
- Symptoms
- List of Symptoms/Signs
- Biology and Ecology
- Natural enemies
- Notes on Natural Enemies
- Impact
- Diagnosis
- Detection and Inspection
- Similarities to Other Species/Conditions
- Prevention and Control
- References
- Distribution Maps
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Top of pageIdentity
Top of pagePreferred Scientific Name
- Chrysomphalus aonidum (Linnaeus, 1758)
Preferred Common Name
- circular scale
Other Scientific Names
- Aonidiella ficorum Ashmead
- Aspidiotus (Chrysomphalus) aonidum (Linnaeus) Hempel, 1900
- Aspidiotus (Chrysomphalus) ficus (Ashmead) Berlese, 1896
- Aspidiotus aonidum (Linnaeus) Cockerell, 1905
- Aspidiotus ficorum Ashmead
- Aspidiotus ficus (Ashmead) Comstock, 1881
- Chrysomphalus ficus Ashmead, 1880
- Coccus aonidum Linnaeus, 1758
International Common Names
- English: black scale; circular black scale; circular purple scale; citrus black scale; Egyptian black scale; fig scale; Florida red scale; purple scale; red spotted scale
- Spanish: cochinilla circular negra; cochinilla redonda obscura; escama negra del naranjo (Chile); escama roja de Florida; queresa redonda marron
- French: chermes de la Floride; pou de Floride; pou rouge de Floride
- Portuguese: cabeca de prego; escama prego
Local Common Names
- Brazil: escama cabeca de prego
- China: orange brown scale
- Germany: Schildlaus, Rote Florida-; Schildlaus, Schwarze Teller-
- Israel: haknima hashchora
- Italy: Cocciniglia di Florida
- South Africa: ronde persdopluis
- Suriname: rode citrusschildluis
- Turkey: kirmizi kosnil
EPPO code
- CHRYFI (Chrysomphalus aonidum)
Taxonomic Tree
Top of page- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Arthropoda
- Subphylum: Uniramia
- Class: Insecta
- Order: Hemiptera
- Suborder: Sternorrhyncha
- Unknown: Coccoidea
- Family: Diaspididae
- Genus: Chrysomphalus
- Species: Chrysomphalus aonidum
Notes on Taxonomy and Nomenclature
Top of page
Apart from a single synonymy, and various changes in generic assignment associated with revision of diaspidid taxonomy, the identity of C. aonidum has never been in doubt.
Description
Top of page
Adult and intermediate-stage females form flat to moderately convex, circular scales up to 2 mm in diameter, each with a slightly raised, sub-central point which is sometimes pale. If the scale is lifted off with the point of a needle, the insect beneath is yellow and up to 1.7 mm long. Male scales are slightly paler than female scales, and are elongate-oval and half the size. The adult male is 0.7 mm long and has a single pair of wings, two pairs of simple eyes, no mouthparts and very long genitalia. First-instar nymphs are 0.3 mm long and have legs but soon settle to form circular white scales (the whitecap stage) up to 0.4 mm across. These become incorporated into the scales of subsequent stages, forming the paler subcentral point.
Distribution
Top of pageC. aonidum is a tropical species, apparently native to the Oriental region (Gill, 1997) but it has been dispersed widely in tropical and subtropical parts of the world, mostly in association with the citrus industry. In northern countries in its range, this species occurs under glass. In 1997, there were no known infestations in California, USA (Gill, 1997). The species has been intercepted in quarantine inspections in Oman and the Netherlands. It was found in Zanzibar in 1915 and has also been found in the UK (CP Malumphy, Central Science Laboratory, UK, personal communication, 1996).
In March 2004, C. aonidum was identified from glasshouses associated with the Auckland Domain Gardens. A joint MAF and Auckland City Council containment programme is believed to have successfully eradicated this scale; monitoring is continuing. C. aonidum has not been detected alive in unprotected environments in New Zealand (Biosecurity New Zealand, 2006).
A record of C. aonidum in Singapore (CIE, 1988; EPPO, 2014) published in previous versions of the Compendium was based on an old record which is now considered unreliable.
The distribution map includes records from the collection held at the Natural History Museum, UK, cited as (NHM, date of collection).
Distribution Table
Top of pageThe distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
Last updated: 30 Jun 2021| Continent/Country/Region | Distribution | Last Reported | Origin | First Reported | Invasive | Reference | Notes |
|---|---|---|---|---|---|---|---|
Africa |
|||||||
| Algeria | Present | ||||||
| Burundi | Present | ||||||
| Comoros | Present | ||||||
| Egypt | Present | ||||||
| Ethiopia | Present | ||||||
| Guinea | Present | ||||||
| Kenya | Present | ||||||
| Madagascar | Present | ||||||
| Malawi | Present | ||||||
| Mauritius | Present | ||||||
| Morocco | Present | ||||||
| Mozambique | Present | ||||||
| Nigeria | Present | ||||||
| Réunion | Present | ||||||
| Senegal | Present | ||||||
| Seychelles | Present | ||||||
| South Africa | Present | ||||||
| Sudan | Present | ||||||
| Tanzania | Present | ||||||
| -Zanzibar Island | Present | ||||||
| Tunisia | Present | ||||||
| Uganda | Present | ||||||
| Zambia | Present | ||||||
| Zimbabwe | Present | ||||||
Asia |
|||||||
| Bhutan | Present | ||||||
| British Indian Ocean Territory | Present | ||||||
| China | Present, Widespread | ||||||
| -Fujian | Present | ||||||
| -Guangdong | Present | ||||||
| -Guangxi | Present | ||||||
| -Guizhou | Present | ||||||
| -Hainan | Present | ||||||
| -Hebei | Present | ||||||
| -Hubei | Present | ||||||
| -Hunan | Present | ||||||
| -Inner Mongolia | Present | ||||||
| -Jiangsu | Present | ||||||
| -Jiangxi | Present | ||||||
| -Shandong | Present | ||||||
| -Sichuan | Present | ||||||
| -Yunnan | Present | ||||||
| -Zhejiang | Present | ||||||
| Hong Kong | Present | ||||||
| India | Present | ||||||
| -Andhra Pradesh | Present | ||||||
| -Assam | Present | ||||||
| -Gujarat | Present | ||||||
| -Karnataka | Present | ||||||
| -Kerala | Present | ||||||
| -Madhya Pradesh | Present | ||||||
| -Maharashtra | Present | ||||||
| -Tamil Nadu | Present | ||||||
| -Tripura | Present | ||||||
| -West Bengal | Present | ||||||
| Indonesia | Present | ||||||
| -Java | Present | ||||||
| -Sulawesi | Present | ||||||
| -Sumatra | Present | ||||||
| Israel | Present, Widespread | ||||||
| Japan | Present | ||||||
| -Bonin Islands | Present | ||||||
| -Honshu | Present | ||||||
| -Kyushu | Present | ||||||
| -Ryukyu Islands | Present | ||||||
| -Shikoku | Present | ||||||
| Jordan | Present | ||||||
| Lebanon | Present | ||||||
| Malaysia | Present | ||||||
| -Peninsular Malaysia | Present | ||||||
| -Sabah | Present | ||||||
| Myanmar | Present | ||||||
| North Korea | Present | ||||||
| Oman | Present | ||||||
| Pakistan | Present | ||||||
| Philippines | Present | ||||||
| Saudi Arabia | Present | ||||||
| Singapore | Absent, Unconfirmed presence record(s) | Original citation: Agri-Food & Veterinary Authority of Singapore, 2015, personal communication | |||||
| South Korea | Present | ||||||
| Sri Lanka | Present | ||||||
| Syria | Present | ||||||
| Taiwan | Present | ||||||
| Thailand | Present | ||||||
| Turkey | Present | ||||||
| Vietnam | Present | ||||||
| Yemen | Present | ||||||
Europe |
|||||||
| Belgium | Present | ||||||
| Croatia | Present, Few occurrences | ||||||
| Cyprus | Present | ||||||
| Czechia | Present | ||||||
| Federal Republic of Yugoslavia | Present | ||||||
| France | Present | ||||||
| Germany | Present | ||||||
| Greece | Present | ||||||
| Hungary | Present, Few occurrences | ||||||
| Italy | Present, Few occurrences | ||||||
| Malta | Present | ||||||
| Netherlands | Present | ||||||
| Poland | Present | Original citation: |
|||||
| Portugal | Present, Localized | ||||||
| -Madeira | Present | ||||||
| Romania | Present | ||||||
| Spain | Present | ||||||
| -Balearic Islands | Present | ||||||
| -Canary Islands | Present | ||||||
North America |
|||||||
| Barbados | Present | ||||||
| Bermuda | Present | ||||||
| Cayman Islands | Present | ||||||
| Costa Rica | Present | ||||||
| Cuba | Present | ||||||
| Dominica | Present | ||||||
| Dominican Republic | Present | ||||||
| El Salvador | Present | ||||||
| Guadeloupe | Present | ||||||
| Guatemala | Present | ||||||
| Haiti | Present | ||||||
| Honduras | Present | ||||||
| Jamaica | Present | ||||||
| Martinique | Present | ||||||
| Mexico | Present | ||||||
| Montserrat | Present | ||||||
| Panama | Present | ||||||
| Puerto Rico | Present | ||||||
| Saint Lucia | Present | ||||||
| Saint Vincent and the Grenadines | Present | ||||||
| Trinidad and Tobago | Present | ||||||
| U.S. Virgin Islands | Present | ||||||
| United States | Present, Localized | ||||||
| -California | Present | ||||||
| -District of Columbia | Present | ||||||
| -Florida | Present | ||||||
| -Hawaii | Present | ||||||
| -Maryland | Present | ||||||
| -Mississippi | Present | ||||||
| -Texas | Present | ||||||
| -Virginia | Present | ||||||
Oceania |
|||||||
| American Samoa | Present | ||||||
| Australia | Present, Localized | ||||||
| -New South Wales | Present | ||||||
| -Northern Territory | Present | ||||||
| -Queensland | Present | ||||||
| -Tasmania | Present | ||||||
| Cook Islands | Present | Original citation: Maddison (1976) | |||||
| Federated States of Micronesia | Present | ||||||
| Fiji | Present | ||||||
| French Polynesia | Present, Localized | ||||||
| Kiribati | Present | ||||||
| New Caledonia | Present | ||||||
| New Zealand | Absent, Eradicated | ||||||
| Niue | Present | Original citation: Maddison (1976) | |||||
| Papua New Guinea | Present | ||||||
| Samoa | Present | ||||||
| Solomon Islands | Present | Original citation: Williams and Watson (1988) | |||||
| Tuvalu | Present | ||||||
South America |
|||||||
| Argentina | Present | ||||||
| Brazil | Present | ||||||
| -Acre | Present | ||||||
| -Amazonas | Present | ||||||
| -Bahia | Present | ||||||
| -Maranhao | Present | ||||||
| -Mato Grosso | Present | ||||||
| -Minas Gerais | Present | ||||||
| -Para | Present | ||||||
| -Paraiba | Present | ||||||
| -Parana | Present | ||||||
| -Pernambuco | Present | ||||||
| -Rio de Janeiro | Present | ||||||
| -Rio Grande do Norte | Present | ||||||
| -Rio Grande do Sul | Present | ||||||
| -Santa Catarina | Present | ||||||
| -Sao Paulo | Present | ||||||
| Chile | Present | ||||||
| -Easter Island | Present | ||||||
| Colombia | Present | ||||||
| French Guiana | Present | ||||||
| Guyana | Present | ||||||
| Paraguay | Present | ||||||
| Suriname | Present | ||||||
| Uruguay | Present | ||||||
| Venezuela | Present | ||||||
Risk of Introduction
Top of page
C. aonidum is already fairly widespread, particularly in citrus-growing regions of the world. As global warming progresses, its distribution is likely to extend north- and southwards with the increase of citrus-producing areas. Countries with new or developing citrus industries just outside the currently known distribution of C. aonidum (CIE, 1988) will need to be vigilant to exclude the scale if possible. The scale may also become a problem on ornamental plants in these countries, and could become a pest of ornamentals under glass in temperate countries, as it has done in Hungary (Reiderné and Kozár, 1994). It is mentioned on quarantine lists (Burger and Ulenburg, 1990).
Hosts/Species Affected
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C. aonidum is a polyphagous species with a preference for citrus, particularly navel and Valencia oranges and grapefruits (Bedford, 1989). It has been recorded from hosts in 77 plant families, including crops, ornamentals, palms and forestry trees (Borchsenius, 1966).
In the laboratory, C. aonidum can be mass-reared for biological control purposes on Citrullus spp. (melons or watermelons) (Bedford, 1989) or on potato tubers or pumpkins (Li and Liao, 1990). In tests, Ceballos and Hernandez (1986) found mass-rearing most successful on Cucurbita pepo.
In the laboratory, C. aonidum can be mass-reared for biological control purposes on Citrullus spp. (melons or watermelons) (Bedford, 1989) or on potato tubers or pumpkins (Li and Liao, 1990). In tests, Ceballos and Hernandez (1986) found mass-rearing most successful on Cucurbita pepo.
Host Plants and Other Plants Affected
Top of page| Plant name | Family | Context | References |
|---|---|---|---|
| Asparagus officinalis (asparagus) | Liliaceae | Other | |
| Camellia sinensis (tea) | Theaceae | Other | |
| Carica papaya (pawpaw) | Caricaceae | Other | |
| Cinnamomum verum (cinnamon) | Lauraceae | Other | |
| Citrus | Rutaceae | Main | |
| Citrus aurantiifolia (lime) | Rutaceae | Main | |
| Citrus limon (lemon) | Rutaceae | Main | |
| Citrus maxima (pummelo) | Rutaceae | Main | |
| Citrus reticulata (mandarin) | Rutaceae | Other | |
| Citrus sinensis (navel orange) | Rutaceae | Main | |
| Citrus x paradisi (grapefruit) | Rutaceae | Main | |
| Cocos nucifera (coconut) | Arecaceae | Other | |
| Dracaena | Agavaceae | Other | |
| Dracaena reflexa | Agavaceae | Other | |
| Gossypium (cotton) | Malvaceae | Other | |
| Lauraceae | Lauraceae | Other | |
| Malus domestica (apple) | Rosaceae | Other | |
| Mangifera indica (mango) | Anacardiaceae | Other | |
| Musa (banana) | Musaceae | Other | |
| Musa x paradisiaca (plantain) | Musaceae | Other | |
| Phoenix dactylifera (date-palm) | Arecaceae | Other | |
| Pinus (pines) | Pinaceae | Other | |
| Yucca decipiens | Agavaceae | Other |
Symptoms
Top of page
C. aonidum is a leaf-infesting species, but in high-density infestations it may spread to fruits, stems and trunks, and may cause premature leaf and fruit drop and stem dieback. The scales appear as circular dark spots.
An infestation appears as dark-purple to reddish-brown or black spots with paler margins, on both surfaces of shaded leaves of the host plant. Heavy infestations cause yellowing of the leaves, followed by defoliation of part or all of the host. C. aonidum prefers shade and is therefore most common in the lower part of the canopy.
An infestation appears as dark-purple to reddish-brown or black spots with paler margins, on both surfaces of shaded leaves of the host plant. Heavy infestations cause yellowing of the leaves, followed by defoliation of part or all of the host. C. aonidum prefers shade and is therefore most common in the lower part of the canopy.
List of Symptoms/Signs
Top of page| Sign | Life Stages | Type |
|---|---|---|
| Fruit / discoloration | ||
| Fruit / external feeding | ||
| Fruit / lesions: black or brown | ||
| Fruit / premature drop | ||
| Leaves / abnormal colours | ||
| Leaves / abnormal leaf fall | ||
| Leaves / honeydew or sooty mould | ||
| Leaves / necrotic areas | ||
| Stems / dieback | ||
| Stems / external feeding |
Biology and Ecology
Top of page
Reproduction in C. aonidum is sexual; no evidence of parthenogenesis has been recorded. The sex ratio in C. aonidum has been found to be biased in favour of females (Nur, 1990). Each adult female lays about 50-150 oval eggs under the scale over a period of 1-8 weeks, depending on the part of the plant infested (those on the leaves being less fecund than those infesting fruits) (Rose and DeBach, 1978). Eggs hatch under the scale and the first-instar nymphs or crawlers walk about to find a suitable feeding site before settling to a sessile lifestyle. The second-instar nymphs are the main feeding stage in both sexes. Development to adult takes 7-16 weeks according to temperature. In California, USA, C. aonidum has up to six generations per year (Gill, 1997). In countries with a cold winter, such as Taiwan, there may be three distinct generations per year (Su, 1983), while in tropical conditions (and heated greenhouses) breeding is continuous and generations are asynchronous.
C. aonidum has a preference for humid environments and cannot tolerate freezing temperatures. It tends to prefer the lower and central parts of mature citrus trees and rarely infests green wood (Rose and DeBach, 1978). Male stages are rather more tolerant of lower humidity than females, so male scales are more often found on the upper surface of the leaf while females congregate on lower leaf surfaces (Bedford, 1989). Like other diaspidid scale insects, C. aonidum suffers increased mortality in heavy rain and reaches high population levels during dry weather.
The first-instar stage is the sole dispersal stage. Each crawler walks to an exposed position on the plant, from which air currents may carry it as much as several tens of kilometres away (Greathead, 1990). Passing animals or people can also can carry the crawlers over great distances. Movement of infested planting material or produce is the main way in which C. aonidum has been introduced to other countries.
This species has 2n=8 chromosomes (Nur, 1990).
C. aonidum has a preference for humid environments and cannot tolerate freezing temperatures. It tends to prefer the lower and central parts of mature citrus trees and rarely infests green wood (Rose and DeBach, 1978). Male stages are rather more tolerant of lower humidity than females, so male scales are more often found on the upper surface of the leaf while females congregate on lower leaf surfaces (Bedford, 1989). Like other diaspidid scale insects, C. aonidum suffers increased mortality in heavy rain and reaches high population levels during dry weather.
The first-instar stage is the sole dispersal stage. Each crawler walks to an exposed position on the plant, from which air currents may carry it as much as several tens of kilometres away (Greathead, 1990). Passing animals or people can also can carry the crawlers over great distances. Movement of infested planting material or produce is the main way in which C. aonidum has been introduced to other countries.
This species has 2n=8 chromosomes (Nur, 1990).
Natural enemies
Top of page| Natural enemy | Type | Life stages | Specificity | References | Biological control in | Biological control on |
|---|---|---|---|---|---|---|
| Agistemus exsertus | Predator | Adults; Arthropods|Nymphs | ||||
| Aphytis chrysomphali | Parasite | Adults; Eggs; Arthropods|Larvae; Arthropods|Nymphs; Arthropods|Pupae | ||||
| Aphytis columbi | Parasite | Adults; Arthropods|Nymphs | ||||
| Aphytis holoxanthus | Parasite | Adults; Arthropods|Nymphs | Argentina; Australia; Australia; Queensland; Brazil; Egypt; Hawaii; Israel; Lebanon; Mexico; Peru; South Africa; Texas | Citrus | ||
| Aphytis lepidosaphes | Parasite | |||||
| Aphytis lingnanensis | Parasite | Arthropods|Nymphs | ||||
| Aphytis philippinensis | Parasite | |||||
| Aphytis pinnaspidis | Parasite | |||||
| Aprostocetus purpureus | Parasite | India | Michelia champaca | |||
| Arrhenophagus chionaspidis | Parasite | |||||
| Beauveria bassiana | Pathogen | |||||
| Cardiastethus nazarenus | Predator | Adults; Arthropods|Nymphs | ||||
| Cheletogenes ornatus | Predator | Adults; Arthropods|Nymphs | ||||
| Chilocorus circumdatus | Predator | Adults; Eggs; Arthropods|Larvae; Arthropods|Nymphs; Arthropods|Pupae | ||||
| Chilocorus distigma | Predator | |||||
| Chilocorus kuwanae | Predator | Adults; Arthropods|Nymphs | ||||
| Chilocorus nigrita | Predator | Adults; Arthropods|Nymphs | ||||
| Chilocorus nigritus | Predator | Adults; Eggs; Arthropods|Larvae; Arthropods|Nymphs; Arthropods|Pupae | ||||
| Chilocorus renipustulatus | Predator | Adults; Eggs; Arthropods|Larvae; Arthropods|Nymphs; Arthropods|Pupae | ||||
| Comperiella bifasciata | Parasite | Arthropods|Nymphs | Egypt; Israel; Philippines; South Africa | Citrus; Cocos nucifera; Ficus carica | ||
| Comperiella pia | Parasite | Arthropods|Nymphs | ||||
| Cryptognatha nodiceps | Predator | Adults; Arthropods|Nymphs | Philippines | Cocos nucifera | ||
| Cycloneda sanguinea | Predator | Adults; Arthropods|Nymphs | ||||
| Encarsia amicula | Parasite | |||||
| Encarsia aurantii | Parasite | |||||
| Encarsia citrina | Parasite | Arthropods|Nymphs | ||||
| Encarsia elongata | Parasite | |||||
| Encarsia herndoni | Parasite | Adults; Arthropods|Nymphs | ||||
| Encarsia lounsburyi | Parasite | Adults; Arthropods|Nymphs | ||||
| Euseius gossipi | Predator | Adults; Arthropods|Nymphs | ||||
| Habrolepis pascuorum | Parasite | |||||
| Metaphycus helvolus | Parasite | |||||
| Mycosphaerella tassiana | Pathogen | |||||
| Nectria flammea | Pathogen | |||||
| Pharoscymnus horni | Predator | Adults; Eggs; Arthropods|Larvae; Arthropods|Nymphs; Arthropods|Pupae | ||||
| Podonectria coccicola | Pathogen | |||||
| Pseudhomalopoda elongata | Parasite | Arthropods|Nymphs | ||||
| Pseudhomalopoda prima | Parasite | Arthropods|Nymphs | ||||
| Pseudoazya trinitatis | Predator | Adults; Arthropods|Nymphs | Philippines | Cocos nucifera | ||
| Pteroptrix chinensis | Parasite | Adults; Arthropods|Nymphs | Hawaii | |||
| Pteroptrix smithi | Parasite | Arthropods|Nymphs | Israel; Mexico | Citrus | ||
| Rhyzobius lophanthae | Predator | Adults; Eggs; Arthropods|Larvae; Arthropods|Nymphs; Arthropods|Pupae | Philippines | Cocos nucifera | ||
| Rhyzobius pulchellus | Predator | Adults; Arthropods|Nymphs | ||||
| Scymnus interruptus | Predator | Adults; Arthropods|Nymphs | ||||
| Scymnus severini | Predator | Adults; Arthropods|Nymphs | ||||
| Signiphora flavopalliata | Parasite | |||||
| Sukunahikona popei | Predator | Adults; Arthropods|Nymphs | ||||
| Telsimia nitida gemmosa | Predator | Adults; Arthropods|Nymphs |
Notes on Natural Enemies
Top of page
Two parasite species, Aphytis holoxanthus and Pteroptrix smithi, are the main biological control agents used against C. aonidum. These were introduced to Israel from Hong Kong in 1956-57 and both established. A. holoxanthus is a very efficient parasite (Steinberg et al., 1987) and quickly brought populations of C. aonidum under control, but subsequently P. smithi has become dominant in the coastal strip, possibly because A. holoxanthus populations fall in autumn and winter in these areas whereas P. smithi populations remain high throughout the year (Steinberg et al., 1986).
The endemic coccinellid Chilocorus bipustulatus was recorded as a useful predator on C. aonidum and other scale insects in citrus groves in Israel by Podoler and Henen (1986).
A. holoxanthus was introduced from Israel to Cyprus and Texas in 1959, to California in 1960 and to Queensland, Australia in 1974, where it displaced the native parasitoid, Aphytis columbi (Smith, 1978). From California, it was introduced to Florida in 1960, Brazil in 1962, Egypt in 1963 and Lebanon in 1965, but the success of the last three introductions is not known (Rosen and DeBach, 1978).
In Taiwan, A. holoxanthus has given up to 57% parasitism and has maintained C. aonidum populations below economic levels (Lin and Tao, 1974).
In South Africa, A. holoxanthus has proved highly effective against C. aonidum on citrus, sometimes giving parasitism levels as high as 90-100% (Bedford, 1989). It is used as part of an integrated pest management programme and has reduced the cost of pesticides to the industry by at least 50%; C. aonidum is now rare in South African orchards.
Comperiella bifasciata was introduced to South Africa accidentally and was mass-reared and released, but could not compete with A. holoxanthus and apparently died out (Bedford, 1989). The coccinellid, Rhyzobius lophanthae, is recorded as a useful predator of C. aonidum in South Africa (Bedford, 1989).
In Texas, C. aonidum used to be controlled by the parasites Pseudhomalopoda elongata and P. prima, but these died out in the winter of 1951 and had to be re-introduced from Florida in 1955 when scale populations escalated. However, control by these parasites was inadequate and led to the introduction of A. holoxanthus from Israel in 1959 (Rosen and DeBach, 1978).
The main hymenopteran parasitoid attacking C. aonidum in Suriname is Aphytis chrysomphali (Brussel and Bhola, 1970). Signophora fax is a primary or secondary parasitoid of C. aonidum in Argentina (Teran et al., 1985).
In India, A. chrysomphali, has been recorded attacking C. aonidum (Das, 1988). The most effective predators of C. aonidum on tea in India are the coccinellids Chilocorus circumdatus (Das et al., 1988) and Pharoscymnus horni in Assam (Das and Gope, 1984). The coccinellid Sukunahikona popei was described as a predator of C. aonidum on coconut palms in Gujarat by Vazirani (1982). A parasitic fungus, Podonectria coccicola, has also been recorded killing C. aonidum in Coorg District, India (Rao, 1979).
Aspidiotiphagus lounsburyi [Encarsia lounsburyi] was recorded attacking C. aonidum in Cuba by Ceballos et al. (1988).
Damaging outbreaks of diaspidid scales, including C. aonidum in the Seychelles in the 1930s, were controlled by introduction of the coccinellid Chilocorus distigma from East Africa in 1936 and C. nigritus from Coimbatore, India in 1938 (Veysey-Fitzgerald, 1941, 1953).
In the Philippines, two species of the coccinellid genus Pseudoscymnus and a species of Telsimia are reported as feeding on C. aonidum by Palacio et al. (1984).
In China, the parasitic fungi Fusarium coccophilum [Nectria flammea], Beauvaria bassiana, Podonectria coccicola and Verticillium sp. were recorded killing C. aonidum in Fujian Province (Gao and Ouyang, 1981).
The endemic coccinellid Chilocorus bipustulatus was recorded as a useful predator on C. aonidum and other scale insects in citrus groves in Israel by Podoler and Henen (1986).
A. holoxanthus was introduced from Israel to Cyprus and Texas in 1959, to California in 1960 and to Queensland, Australia in 1974, where it displaced the native parasitoid, Aphytis columbi (Smith, 1978). From California, it was introduced to Florida in 1960, Brazil in 1962, Egypt in 1963 and Lebanon in 1965, but the success of the last three introductions is not known (Rosen and DeBach, 1978).
In Taiwan, A. holoxanthus has given up to 57% parasitism and has maintained C. aonidum populations below economic levels (Lin and Tao, 1974).
In South Africa, A. holoxanthus has proved highly effective against C. aonidum on citrus, sometimes giving parasitism levels as high as 90-100% (Bedford, 1989). It is used as part of an integrated pest management programme and has reduced the cost of pesticides to the industry by at least 50%; C. aonidum is now rare in South African orchards.
Comperiella bifasciata was introduced to South Africa accidentally and was mass-reared and released, but could not compete with A. holoxanthus and apparently died out (Bedford, 1989). The coccinellid, Rhyzobius lophanthae, is recorded as a useful predator of C. aonidum in South Africa (Bedford, 1989).
In Texas, C. aonidum used to be controlled by the parasites Pseudhomalopoda elongata and P. prima, but these died out in the winter of 1951 and had to be re-introduced from Florida in 1955 when scale populations escalated. However, control by these parasites was inadequate and led to the introduction of A. holoxanthus from Israel in 1959 (Rosen and DeBach, 1978).
The main hymenopteran parasitoid attacking C. aonidum in Suriname is Aphytis chrysomphali (Brussel and Bhola, 1970). Signophora fax is a primary or secondary parasitoid of C. aonidum in Argentina (Teran et al., 1985).
In India, A. chrysomphali, has been recorded attacking C. aonidum (Das, 1988). The most effective predators of C. aonidum on tea in India are the coccinellids Chilocorus circumdatus (Das et al., 1988) and Pharoscymnus horni in Assam (Das and Gope, 1984). The coccinellid Sukunahikona popei was described as a predator of C. aonidum on coconut palms in Gujarat by Vazirani (1982). A parasitic fungus, Podonectria coccicola, has also been recorded killing C. aonidum in Coorg District, India (Rao, 1979).
Aspidiotiphagus lounsburyi [Encarsia lounsburyi] was recorded attacking C. aonidum in Cuba by Ceballos et al. (1988).
Damaging outbreaks of diaspidid scales, including C. aonidum in the Seychelles in the 1930s, were controlled by introduction of the coccinellid Chilocorus distigma from East Africa in 1936 and C. nigritus from Coimbatore, India in 1938 (Veysey-Fitzgerald, 1941, 1953).
In the Philippines, two species of the coccinellid genus Pseudoscymnus and a species of Telsimia are reported as feeding on C. aonidum by Palacio et al. (1984).
In China, the parasitic fungi Fusarium coccophilum [Nectria flammea], Beauvaria bassiana, Podonectria coccicola and Verticillium sp. were recorded killing C. aonidum in Fujian Province (Gao and Ouyang, 1981).
Impact
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The most important crop damaged by C. aonidum is citrus: damage has been recorded in the USA (Florida, Texas), Brazil, Mexico, Cuba, Puerto Rico, Central America, Trinidad, Colombia, Venezuela, Argentina, Paraguay, Uruguay, Italy and North Africa, Lebanon, Egypt, Israel, South Africa, India, Pakistan, Australia and China (Rose and DeBach, 1978; Rose, 1990) and Western Samoa (Maddison, 1976). According to Bedford (1989), in unsprayed citrus orchards in South Africa C. aonidum used to cause almost complete defoliation of individual trees, which would produce hardly any crop the following season. Heavy infestation of fruits resulted in up to 100% culling at the packhouse. Expenditure on insecticide sprays to control the scale was high until the introduction of effective biological control of C. aonidum reduced infestation by over 50%. Heavy infestation of citrus foliage in New Caledonia resulted in death of trees (Cohic, 1950). In 1976, it was estimated that C. aonidum caused an annual loss on citrus in Texas of US$3.85 million (Kosztarab, 1990).
C. aonidum is a pest of olive in Israel and Turkey (Argyriou, 1990). Danzig and Pellizzari (1998) refer to the species as a dangerous pest in the Palaearctic region. In Poland, it causes serious damage to ornamental plants in glasshouses (Labanowsky, 1999). It has been recorded severely damaging pine seedlings in Papua New Guinea (Szent-Ivany and Stevens, 1966), and causes problems on several economically important hosts in Brazil (Claps et al., 2001). Foldi (2001) listed it as an occasional pest in France. C. aonidum has been recorded causing serious damage to young tea in India (Das, 1974); as a serious pest of bananas in the Caribbean and Central America (Rose and DeBach, 1978) and as an occasional pest of bananas in Israel, where heavy infestations developed in high temperatures and made the fruit unmarketable (Chua and Wood, 1990). It is a problem on coconuts in the Philippines (Rose and DeBach, 1978) and was a serious pest of coconut in the Seychelles in the 1930s, causing yellow patches on infested pinnae and death of whole leaves, leading to reductions in yield in severe outbreaks (Vesey-Fitzgerald, 1940).
C. aonidum is a pest of olive in Israel and Turkey (Argyriou, 1990). Danzig and Pellizzari (1998) refer to the species as a dangerous pest in the Palaearctic region. In Poland, it causes serious damage to ornamental plants in glasshouses (Labanowsky, 1999). It has been recorded severely damaging pine seedlings in Papua New Guinea (Szent-Ivany and Stevens, 1966), and causes problems on several economically important hosts in Brazil (Claps et al., 2001). Foldi (2001) listed it as an occasional pest in France. C. aonidum has been recorded causing serious damage to young tea in India (Das, 1974); as a serious pest of bananas in the Caribbean and Central America (Rose and DeBach, 1978) and as an occasional pest of bananas in Israel, where heavy infestations developed in high temperatures and made the fruit unmarketable (Chua and Wood, 1990). It is a problem on coconuts in the Philippines (Rose and DeBach, 1978) and was a serious pest of coconut in the Seychelles in the 1930s, causing yellow patches on infested pinnae and death of whole leaves, leading to reductions in yield in severe outbreaks (Vesey-Fitzgerald, 1940).
Diagnosis
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Authoritative identification requires skilful preparation of slide mounts of adult females for microscopic examination by a specialist.
For authoritative identification, slide-mounted adult female specimens should be examined under a compound light microscope. Diagnostic characteristics of the adult female are that the paraphyses are only associated with the lobes and are all longer than median lobes. The prosoma are entirely membraneous. A submarginal prepygidial macroduct cluster is present on either side of the second abdominal segment only. The metathorax has an elongate, pointed marginal spur present on either side. A redescription of C. aonidum (as C. ficus) is provided by Ferris (1938).
For authoritative identification, slide-mounted adult female specimens should be examined under a compound light microscope. Diagnostic characteristics of the adult female are that the paraphyses are only associated with the lobes and are all longer than median lobes. The prosoma are entirely membraneous. A submarginal prepygidial macroduct cluster is present on either side of the second abdominal segment only. The metathorax has an elongate, pointed marginal spur present on either side. A redescription of C. aonidum (as C. ficus) is provided by Ferris (1938).
Detection and Inspection
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Examine plants closely for dark spots on the leaves, especially in shady parts of the plant. Good light conditions are essential and in poor light, a powerful flashlight is helpful. A large hand lens may assist in recognition of small, immature stages.
Similarities to Other Species/Conditions
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First-instar nymphs of C. aonidum are difficult to distinguish from some other species of diaspidid scale found on citrus.
On palms, C. aonidum could be confused with Hemiberlesia palmae in life, but these species are quite distinct when slide-mounted. On ornamental plants, a non-specialist could confuse C. aonidum in life with C. bifaciculatus or species of Lindingaspis and Melanaspis, but the slide-mounted females are quite distinct.
On palms, C. aonidum could be confused with Hemiberlesia palmae in life, but these species are quite distinct when slide-mounted. On ornamental plants, a non-specialist could confuse C. aonidum in life with C. bifaciculatus or species of Lindingaspis and Melanaspis, but the slide-mounted females are quite distinct.
Prevention and Control
Top of pageDue to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.
Regulatory ControlPre-export inspection should be sufficient. Leaves, particularly lower surfaces, and fruits should be examined.
Chemical Control
Numerous citrus-producing countries, such as Israel and South Africa, have controlled C. aonidum and other scale insect pests of citrus with insecticides (particularly organophosphates). However, the long-term use of pesticides is expensive, can be environmentally damaging and leads to outbreaks of other pests due to elimination of their natural controls and development of pesticide resistance in the scales.
Biological Control
The development of effective biological controls has greatly reduced the importance of C. aonidum in many citrus-producing countries, such as Israel, Mexico and Australia. In South Africa, expenditure on insecticide sprays to control the scale on citrus was high until the introduction of effective biological control of C. aonidum reduced it by over 50% (Bedford, 1989).
Two parasite species, Aphytis holoxanthus and Pteroptrix smithi, are the main biological control agents used against C. aonidum. These were introduced to Israel from Hong Kong in 1956-57 and both established. A. holoxanthus is a very efficient parasite (Steinberg et al., 1987) and quickly brought populations of C. aonidum under control, but subsequently P. smithi has become dominant in the coastal strip, possibly because A. holoxanthus populations fall in autumn and winter in these areas whereas P. smithi populations remain high throughout the year (Steinberg et al., 1986).
A. holoxanthus was introduced from Israel to Cyprus and Texas in 1959, to California in 1960 and to Queensland, Australia in 1974, where it displaced the native parasitoid, Aphytis columbi (Smith, 1978). From California, it was introduced to Florida in 1960, to Brazil in 1962, to Egypt in 1963 and to Lebanon in 1965, but the success of the last three introductions is not known (Rosen and DeBach, 1978).
Comperiella bifasciata was introduced to South Africa accidentally and was mass-reared and released, but could not compete with A. holoxanthus and apparently died out (Bedford, 1989). The coccinellid, Rhyzobius lophanthae, is recorded as a useful predator of C. aonidum in South Africa (Bedford, 1989).
In Texas, C. aonidum used to be controlled by the parasites Pseudhomalopoda elongata and P. prima, but these died out in the winter of 1951 and had to be re-introduced from Florida in 1955 when scale populations escalated. However, control by these parasites was inadequate and led to the introduction of A. holoxanthus from Israel in 1959 (Rosen and DeBach, 1978).
Damaging outbreaks of diaspidid scales, including C. aonidum in the Seychelles in the 1930s, were controlled by introduction of the coccinellid Chilocorus distigma from East Africa in 1936 and C. nigritus from Coimbatore, India in 1938 (Veysey-Fitzgerald, 1941, 1953).
In the laboratory, C. aonidum can be mass-reared for biological control purposes on Citrullus spp. (melons or watermelons) (Bedford 1989) or on potato tubers or pumpkins (Li and Liao, 1990). In tests, Ceballos and Hernandez (1986) found mass-rearing most successful on Cucurbita pepo.
IPM Programmes
Since the successful introduction of biological control against C. aonidum in Israel, effective integrated pest management programmes have been developed in Israel (Steinberg et al., 1986, 1987) and South Africa (Bedford, 1989).
In South Africa, Aphytis holoxanthus has proved highly effective against C. aonidum on citrus, sometimes giving parasitism levels as high as 90-100% (Bedford, 1989). It is used as part of an integrated pest management programme and has reduced the cost of pesticides to the industry by at least 50%; C. aonidum is now rare in South African orchards.
References
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Distribution References
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CABI, Undated. Compendium record. Wallingford, UK: CABI
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Claps LE, Wolff VRS, González RH, 2001. (Catálogo de las Diaspididae (Hemiptera: Coccoidea) exóticas de la Argentina, Brasil y Chile)., 14 (4) 9-34.
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Danzig EM, Pellizzari G, 1998. Diaspididae. In: Catalogue of Palaearctic Coccoidea, [ed. by Kozßr F]. Budapest, Hungary: Hungarian Academy of Sciences, Akaprint Nyomdaipari Kft. 172-370.
Gill G, 2005. Spray programme effective against Florida red scale. Biosecurity. 17.
Kawai S, 1980. Scale Insects of Japan in Colours., Tokyo, Japan: National Agriculture Education Association. 455 pp.
Watanabe MA, Tambasco FJ, Costa VA, Nardo EAB de, Facanali R, 2000. (Flutuatpo populacional de cochonilhas de carapata na cultura de citros em municfpios paulistas). In: Laranja, 21 49-64.
Wong CY, Chen SP, Chou LP, 1999. Guidebook to scale insects of Taiwan., Taichung, Taiwan: Taiwan Agricultural Research Institute. 1-98.
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