| Picture | Title | Caption | Copyright |
|---|---|---|---|
| Eggs | A. dispersus, 'spiralling whitefly', eggs on soyabean leaf. | Ernst Neering | |
| Adults | Adult A. dispersus usually have plain white wings, but occasionally have pale or dark spots on the forewings. Pupae secrete copious amounts of white, cottony, flocculent wax. | ©Matthew Cock | |
| Infestation on guava | A. dispersus infestation on guava, Philippines: when abundant they are conspicuous on leaves due to the white flocculence that covers their bodies. | ©Matthew Cock | |
| Pupa | Stained slide preparation of an A. dispersus pupa. | ©Natural History Museum, London | |
| Pupa | Stained slide preparation of an A. dispersus pupa. | ©Natural History Museum, London | |
| Pupa | Stained slide preparation of an A. dispersus pupa. | ©Natural History Museum, London | |
| Adult | Stained slide preparation of an A. dispersus adult. | ©Natural History Museum, London | |
| Adult | Stained slide preparation of an A. dispersus adult. | ©Natural History Museum, London |
Datasheet
Aleurodicus dispersus (whitefly)
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
- Means of Movement and Dispersal
- Pathway Vectors
- Plant Trade
- Wood Packaging
- Impact Summary
- Impact
- 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
- Aleurodicus dispersus Russell, 1965
Preferred Common Name
- whitefly
International Common Names
- English: spiralling whitefly
- Spanish: mosca blanca
- French: aleurode
EPPO code
- ALEDDI (Aleurodicus dispersus)
Taxonomic Tree
Top of page- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Arthropoda
- Subphylum: Uniramia
- Class: Insecta
- Order: Hemiptera
- Suborder: Sternorrhyncha
- Unknown: Aleyrodoidea
- Family: Aleyrodidae
- Genus: Aleurodicus
- Species: Aleurodicus dispersus
Notes on Taxonomy and Nomenclature
Top of page
A. dispersus was first described by Russell (1965) in Florida, USA and many Caribbean and Central American countries. It is located within the Aleurodicinae, the smaller of two subfamilies within the Aleyrodidae, which comprises approximately 100 species. A. dispersus is characterized by distinctive compound and simple pores (Russell, 1965).
Description
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Adult female A. dispersus lay a few to several elliptical, smooth-surfaced, yellow-to-tan coloured eggs (0.3 mm long). The eggs have a short pedicel or subterminal stalk, which is inserted into the host plant during oviposition (Waterhouse and Norris, 1989). The eggs are laid, along with deposits of waxy secretions, in a spiraling pattern.
The first larval stage ('crawler') is the only mobile immature stage (0.32 mm long). During the second larval stage (0.5 mm long), a row of mid-back waxy tufts form on the anterior of the body. During the third larval stage (0.65 mm long), short, evenly-spaced, glass-like, waxy rods emanate from distinctive compound pores along the side of the body (Waterhouse and Norris, 1989). Russell (1965) described the pore structure in detail for each immature stage.
During the early pupal stage (fourth larval stage), sedentary feeding continues (Russell, 1965; Waterhouse and Norris, 1989). Copious amounts of white, cottony flocculent wax, extending from the dorsum, are then secreted by the pupae; more so than for the larval stages. Young pupae are nearly flat dorsally and flat ventrally. Mature pupae (1.06 mm long) have a swollen ventral surface and are surrounded by a band of wax. The waxy rods emanating from each of the large compound pores, which occur in five subdorsal pairs, extend upward and outward from the back. The waxy rods can be up to 8 mm in length (Waterhouse and Norris, 1989). Pupae are colourless or yellowish, nearly oval and 1-1.25 mm long and 0.75-0.90 mm wide (Russell, 1965). Fully mobile adults emerge from the pupae. The pupal cases or puparia are used for identification purposes. Martin (1987, 1996) provided keys to tropical pest species based on pupal morphology.
Adult A. dispersus are white and coated with a fine dust-like waxy secretion. Body length of males 2.28 mm, and females 1.74 mm. Both sexes are winged. Wings are clear soon after emergence, but turn white due to the wax coating after a few hours. Pale or dark spots may occasionally occur on the forewings. Antennae have seven segments and eyes are dark reddish-brown (Waterhouse and Norris, 1989). Adult females do not have pores, while males have numerous circular pores on the abdomen (Russell, 1965).
Wen et al. (1994b) described the morphology, including body size for immatures and adults, of A. dispersus in Taiwan.
The first larval stage ('crawler') is the only mobile immature stage (0.32 mm long). During the second larval stage (0.5 mm long), a row of mid-back waxy tufts form on the anterior of the body. During the third larval stage (0.65 mm long), short, evenly-spaced, glass-like, waxy rods emanate from distinctive compound pores along the side of the body (Waterhouse and Norris, 1989). Russell (1965) described the pore structure in detail for each immature stage.
During the early pupal stage (fourth larval stage), sedentary feeding continues (Russell, 1965; Waterhouse and Norris, 1989). Copious amounts of white, cottony flocculent wax, extending from the dorsum, are then secreted by the pupae; more so than for the larval stages. Young pupae are nearly flat dorsally and flat ventrally. Mature pupae (1.06 mm long) have a swollen ventral surface and are surrounded by a band of wax. The waxy rods emanating from each of the large compound pores, which occur in five subdorsal pairs, extend upward and outward from the back. The waxy rods can be up to 8 mm in length (Waterhouse and Norris, 1989). Pupae are colourless or yellowish, nearly oval and 1-1.25 mm long and 0.75-0.90 mm wide (Russell, 1965). Fully mobile adults emerge from the pupae. The pupal cases or puparia are used for identification purposes. Martin (1987, 1996) provided keys to tropical pest species based on pupal morphology.
Adult A. dispersus are white and coated with a fine dust-like waxy secretion. Body length of males 2.28 mm, and females 1.74 mm. Both sexes are winged. Wings are clear soon after emergence, but turn white due to the wax coating after a few hours. Pale or dark spots may occasionally occur on the forewings. Antennae have seven segments and eyes are dark reddish-brown (Waterhouse and Norris, 1989). Adult females do not have pores, while males have numerous circular pores on the abdomen (Russell, 1965).
Wen et al. (1994b) described the morphology, including body size for immatures and adults, of A. dispersus in Taiwan.
Distribution
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A. dispersus is of Neotropical origin, and is native to Central America and the Caribbean region. It is naturally found in Central and South America, the West Indies and southern Florida, USA. It has been present in the Canary Islands since 1962. During the 1970s it began a rapid expansion of its range. It established in Hawaii in 1978 (Paulson and Kumashiro, 1985). It was first reported in the Philippines in 1982, and during the 1980s it spread throughout the islands of the Pacific (Waterhouse and Norris, 1989). More recently, it has been reported in India, Sri Lanka, Africa, Indonesia, Thailand, Taiwan and northern Australia (Wijesekera and Kudagamage, 1990; Martin, 1990; Kajita et al., 1991; Akinlosotu et al., 1993; Wen et al., 1994b; Palaniswami et al., 1995; Carver and Reid, 1996).
The distribution map includes records based on specimens of A. dispersus from the collection in the Natural History Museum (London, UK): dates of collection are noted in the List of countries (NHM, various dates).
The distribution map includes records based on specimens of A. dispersus from the collection in the Natural History Museum (London, UK): dates of collection are noted in the List of countries (NHM, various dates).
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: 17 Feb 2021| Continent/Country/Region | Distribution | Last Reported | Origin | First Reported | Invasive | Reference | Notes |
|---|---|---|---|---|---|---|---|
Africa |
|||||||
| Benin | Present | ||||||
| Cabo Verde | Present | ||||||
| Cameroon | Present | ||||||
| Congo, Republic of the | Present | ||||||
| Gabon | Present | ||||||
| Ghana | Present | ||||||
| Kenya | Present | ||||||
| Mauritius | Present, Localized | Introduced | Invasive | ||||
| Morocco | Present | ||||||
| Mozambique | Present | ||||||
| Nigeria | Present | Introduced | Invasive | ||||
| Réunion | Present | ||||||
| São Tomé and Príncipe | Present | ||||||
| Senegal | Present | ||||||
| Seychelles | Present | Introduced | |||||
| Tanzania | Present | ||||||
| Togo | Present | Introduced | Invasive | ||||
Asia |
|||||||
| Bangladesh | Present | ||||||
| Brunei | Present | Introduced | Invasive | ||||
| China | Present | ||||||
| -Hainan | Present | Introduced | |||||
| India | Present, Localized | ||||||
| -Andhra Pradesh | Present | ||||||
| -Karnataka | Present | ||||||
| -Kerala | Present | Introduced | Invasive | ||||
| -Lakshadweep | Present | ||||||
| -Maharashtra | Present | ||||||
| -Meghalaya | Present | ||||||
| -Mizoram | Present | ||||||
| -Odisha | Present | ||||||
| -Tamil Nadu | Present | ||||||
| Indonesia | Present | ||||||
| -Java | Present | Introduced | Invasive | ||||
| -Sulawesi | Present | ||||||
| -Sumatra | Present | Introduced | Invasive | ||||
| Laos | Present | Introduced | Invasive | ||||
| Malaysia | Present, Widespread | ||||||
| -Peninsular Malaysia | Present | Introduced | Invasive | ||||
| -Sabah | Present | Introduced | Invasive | ||||
| -Sarawak | Present | Introduced | Invasive | ||||
| Maldives | Present | Introduced | Invasive | ||||
| Myanmar | Present | Introduced | Invasive | ||||
| Philippines | Present | Introduced | Invasive | ||||
| Singapore | Present | Introduced | Invasive | ||||
| Sri Lanka | Present | Introduced | Invasive | ||||
| Taiwan | Present | Introduced | Invasive | ||||
| Thailand | Present | Introduced | Invasive | ||||
| Vietnam | Present | Introduced | Invasive | ||||
Europe |
|||||||
| Netherlands | Absent, Confirmed absent by survey | ||||||
| Portugal | Present, Localized | Introduced | Invasive | ||||
| -Madeira | Present | Introduced | Invasive | ||||
| Spain | Present, Localized | Introduced | Invasive | ||||
| -Canary Islands | Present | Introduced | Invasive | ||||
North America |
|||||||
| Bahamas | Present | ||||||
| Barbados | Present | ||||||
| Belize | Present | ||||||
| Cayman Islands | Present | ||||||
| Costa Rica | Present | ||||||
| Cuba | Present | ||||||
| Dominica | Present | ||||||
| Dominican Republic | Present | ||||||
| Guadeloupe | Present | ||||||
| Guatemala | Present | ||||||
| Haiti | Present | ||||||
| Martinique | Present | ||||||
| Nicaragua | Present | ||||||
| Panama | Present | ||||||
| Puerto Rico | Present | ||||||
| United States | Present | ||||||
| -Florida | Present | ||||||
| -Hawaii | Present | ||||||
Oceania |
|||||||
| American Samoa | Present | ||||||
| Australia | Present, Few occurrences | ||||||
| -Queensland | Present, Few occurrences | ||||||
| Cook Islands | Present | ||||||
| Federated States of Micronesia | Present | ||||||
| Fiji | Present | ||||||
| French Polynesia | Present | ||||||
| Guam | Present | ||||||
| Kiribati | Present | ||||||
| Marshall Islands | Present | ||||||
| Nauru | Present | ||||||
| New Caledonia | Present | ||||||
| Northern Mariana Islands | Present | ||||||
| Palau | Present | ||||||
| Papua New Guinea | Present | ||||||
| Samoa | Present | ||||||
| Solomon Islands | Present | ||||||
| Tokelau | Present | ||||||
| Tonga | Present | ||||||
South America |
|||||||
| Brazil | Present | ||||||
| -Bahia | Present | ||||||
| Colombia | Present | ||||||
| Ecuador | Present | ||||||
| Peru | Present | ||||||
| Venezuela | Present | ||||||
Risk of Introduction
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A. dispersus presents a serious phytosanitary risk to tropical and subtropical areas on the edges of its current range. Quarantine areas have been declared in Queensland, Australia. The movement of plants, plant material, and fruits out of quarantine areas can only proceed after official inspections (Lambkin, 1998). The spread of A. dispersus on citrus is of particular concern, in Australia, Mexico and other countries. Only the climatic limitations will ultimately determine the final distribution of this highly invasive and polyphagous pest. It has not stopped moving yet (2003).
Hosts/Species Affected
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A. dispersus is highly polyphagous, being common on a wide range of different families. Russell (1965) recorded it from 38 genera in 27 plant families in Florida, USA.
In Taiwan, Wen et al. (1994b) listed 144 species of host plant, in 64 families, with host range varying with season. In Indonesia, Kajita et al. (1991) reported A. dispersus attacking 22 plants in 14 families, including ornamentals, shade and fruit trees and annual crops. In Kerala, India, Prathapan (1996) listed 72 host plants, ranked by intensity of infestation.
In addition to the hosts listed, Diospyros philippensis, Elaeocarpus serratus, Heliotropum indicum, Ixeris oldhami, Laguncularia racemosa, Melaleuca leucadendron, Peristeria spp., Pterocarpus spp., Rhus semialata, Sagittaria trifolia and Sideroxylon ferruginium are also secondary hosts of A. dispersus.
In Taiwan, Wen et al. (1994b) listed 144 species of host plant, in 64 families, with host range varying with season. In Indonesia, Kajita et al. (1991) reported A. dispersus attacking 22 plants in 14 families, including ornamentals, shade and fruit trees and annual crops. In Kerala, India, Prathapan (1996) listed 72 host plants, ranked by intensity of infestation.
In addition to the hosts listed, Diospyros philippensis, Elaeocarpus serratus, Heliotropum indicum, Ixeris oldhami, Laguncularia racemosa, Melaleuca leucadendron, Peristeria spp., Pterocarpus spp., Rhus semialata, Sagittaria trifolia and Sideroxylon ferruginium are also secondary hosts of A. dispersus.
Host Plants and Other Plants Affected
Top of pageSymptoms
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In cassava, A. dispersus infestation caused yellowish speckling of the leaves, and in severe infestation the leaves crinkled and curled. Infestation spread from the bottom leaves to the top (Palaniswami et al., 1995).
Copious honeydew is excreted which coats surrounding surfaces and often develops a layer of sooty mould.
Copious honeydew is excreted which coats surrounding surfaces and often develops a layer of sooty mould.
List of Symptoms/Signs
Top of page| Sign | Life Stages | Type |
|---|---|---|
| Leaves / abnormal colours | ||
| Leaves / honeydew or sooty mould | ||
| Leaves / honeydew or sooty mould | ||
| Leaves / honeydew or sooty mould |
Biology and Ecology
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Females, collected in the field in Sri Lanka and studied in the laboratory, each laid 14-26 eggs in a loose spiral on the underside of leaves. The common name of A. dispersus, the spiralling whitefly, is derived from this characteristic egg-laying pattern, although other species of aleurodicine whitefly also lay eggs in spiral patterns (Martin, 1990). The eggs hatched after 7-10 days, the first and second larval instars lasted for 6-9 days in total, the third instar for 5-13 days and the fourth (pupae) 5-16 days. Adults lived for about 2 weeks (Wijesekera and Kudagamage, 1990). The immature stages of A. dispersus are found on the lower leaf surface of host plants. The leaf structure of the host plant appears to affect feeding preference (Wen et al., 1994a). The larval stages and adults feed by sucking phloem sap from leaves. Copious honeydew is excreted which coats surrounding surfaces and often develops a layer of sooty mould when colonies are poorly controlled.
Wen et al. (1994b) described the effects of temperature on development rate and fecundity. Adults were active between 12.3-32.3°C and maximum female fecundity occurred at 25°C. A. dispersus populations were found all year round in southern Taiwan, building up rapidly in October, reaching a peak in November, and then declining gradually after December. The developmental time (from oviposition to eclosion) of the pest at 25°C on poinsettia, canna, guavas and pawpaws was 26.1, 25.0, 29.4 and 26.1 days; immature mortality was 26.9, 24.5, 33.3 and 27.8%; and fecundity was 65.2, 35.8, 51.3 and 58.0 eggs per female, respectively (Wen et al., 1996).
Females begin laying eggs within a few days of emergence, and continue to lay throughout their lifetime. The rate of population growth can be rapid. In one experiment, 20 pairs produced 1549 individuals in 37 days (Waterhouse and Norris, 1989). Unmated females produce only male progeny, while mated females produce a mixture of male and female progeny. Adults are most active in the morning, but mate in the afternoon (Waterhouse and Norris, 1989).
In the USA, A. dispersus is limited to southern coastal areas in Florida where mild winter temperatures occur. Extreme mortality occurs at low temperatures (below 10°C), which limits the northward spread of A. dispersus in the Americas (Cherry, 1979).
Manzano et al. (1995) described the biology of A. dispersus in the Canary Islands. In Karnataka, India, Aishwariya et al. (2007) studied the biology of A. dispersus on guava during the winter, summer and wet seasons.
Wen et al. (1994b) described the effects of temperature on development rate and fecundity. Adults were active between 12.3-32.3°C and maximum female fecundity occurred at 25°C. A. dispersus populations were found all year round in southern Taiwan, building up rapidly in October, reaching a peak in November, and then declining gradually after December. The developmental time (from oviposition to eclosion) of the pest at 25°C on poinsettia, canna, guavas and pawpaws was 26.1, 25.0, 29.4 and 26.1 days; immature mortality was 26.9, 24.5, 33.3 and 27.8%; and fecundity was 65.2, 35.8, 51.3 and 58.0 eggs per female, respectively (Wen et al., 1996).
Females begin laying eggs within a few days of emergence, and continue to lay throughout their lifetime. The rate of population growth can be rapid. In one experiment, 20 pairs produced 1549 individuals in 37 days (Waterhouse and Norris, 1989). Unmated females produce only male progeny, while mated females produce a mixture of male and female progeny. Adults are most active in the morning, but mate in the afternoon (Waterhouse and Norris, 1989).
In the USA, A. dispersus is limited to southern coastal areas in Florida where mild winter temperatures occur. Extreme mortality occurs at low temperatures (below 10°C), which limits the northward spread of A. dispersus in the Americas (Cherry, 1979).
Manzano et al. (1995) described the biology of A. dispersus in the Canary Islands. In Karnataka, India, Aishwariya et al. (2007) studied the biology of A. dispersus on guava during the winter, summer and wet seasons.
Natural enemies
Top of page| Natural enemy | Type | Life stages | Specificity | References | Biological control in | Biological control on |
|---|---|---|---|---|---|---|
| Allograpta obliqua | Predator | Adults/Larvae/Nymphs/Pupae | ||||
| Cheilomenes sexmaculata | Predator | Adults/Nymphs | ||||
| Chilocorus nigrita | Predator | Adults/Larvae/Pupae | ||||
| Chrysopa | Predator | Larvae/Pupae | ||||
| Chrysoperla comanche | Predator | Adults/Nymphs | ||||
| Coelophora inaequalis | Predator | Adults/Larvae/Nymphs/Pupae | ||||
| Cryptolaemus montrouzieri | Predator | |||||
| Curinus coeruleus | Predator | Adults/Larvae/Pupae | ||||
| Delphastus pusillus | Predator | Adults/Nymphs | American Samoa; Hawaii | guavas; polyphagous | ||
| Encarsia guadeloupae | Parasite | |||||
| Encarsia haitiensis | Parasite | Adults/Larvae/Nymphs | Guam; Northern Mariana Islands | guavas; Plumeria | ||
| Encarsia meritoria | Parasite | |||||
| Encarsia nigricephala | Parasite | |||||
| Encarsia sophia | Parasite | |||||
| Encarsia transvena | ||||||
| Encarsiella aleurodici | Parasite | Larvae/Pupae | ||||
| Encarsiella noyesi | Parasite | Larvae/Pupae | ||||
| Euderomphale vittata | Parasite | Larvae | ||||
| Harmonia sedecimnotata | Predator | Adults/Larvae/Nymphs/Pupae | ||||
| Iridomyrmex anceps | Predator | Adults/Nymphs | ||||
| Lecanicillium lecanii | Pathogen | |||||
| Nephaspis amnicola | Predator | Adults/Nymphs | Hawaii | |||
| Nephaspis bicolor | Predator | Adults/Larvae/Pupae | ||||
| Nephaspis oculata | Predator | Adults/Nymphs | ||||
| Olla v-nigrum | Predator | Adults/Larvae/Pupae | ||||
| Paragus serratus | Predator | Adults/Larvae/Nymphs/Pupae | ||||
| Scymnus | Predator | Adults/Larvae/Pupae |
Notes on Natural Enemies
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A. dispersus is recorded as being frequently parasitized in Florida, USA (Russell, 1965). The common parasitoids of A. dispersus on banana in Costa Rica were described by Blanco Metzler and Laprade (1998). Gerling (1990) presented a short key for parasitoids of whiteflies. Clausen (1934) listed natural enemies of Aleyrodidae in tropical Asia, although A. dispersus was probably not present in Asia at that time.
Encarsia haitiensis was believed to be host-specific on A. dispersus (Waterhouse and Norris, 1989); however, E. haitiensis as a parasitoid of A. dispersus is based on a misidentification. The species widely reported in published papers as E. haitiensis or E. near haitiensis is in fact an undescribed species closely related to Encarsia hispida, which also attacks A. dispersus (Polaszek et al., 2004). Hernandez-Suarez et al. (2003) reported E. hispida and Encarsia guadeloupae affecting A. dispersus in the Canary Islands.
Paulson and Kumashiro (1985) described natural enemies of A. dispersus in Hawaii. Kumashiro et al. (1983) described the introduction of two parasitoids and several coccinellids into Hawaii for the biological control of A. dispersus, of which Nephaspis oculatus (N. amnicola) was the most effective coccinellid predator. Yoshida and Mau (1985) described the life history and feeding behaviour of N. oculatus. Although N. oculatus has a wide prey range in laboratory studies, in the field it shows a strong preference for whiteflies. However, it is only effective as a natural enemy within high prey densities. In contrast, E. haitiensis is most effective when whitefly populations are low (Kumashiro et al., 1983).
Encarsia haitiensis was believed to be host-specific on A. dispersus (Waterhouse and Norris, 1989); however, E. haitiensis as a parasitoid of A. dispersus is based on a misidentification. The species widely reported in published papers as E. haitiensis or E. near haitiensis is in fact an undescribed species closely related to Encarsia hispida, which also attacks A. dispersus (Polaszek et al., 2004). Hernandez-Suarez et al. (2003) reported E. hispida and Encarsia guadeloupae affecting A. dispersus in the Canary Islands.
Paulson and Kumashiro (1985) described natural enemies of A. dispersus in Hawaii. Kumashiro et al. (1983) described the introduction of two parasitoids and several coccinellids into Hawaii for the biological control of A. dispersus, of which Nephaspis oculatus (N. amnicola) was the most effective coccinellid predator. Yoshida and Mau (1985) described the life history and feeding behaviour of N. oculatus. Although N. oculatus has a wide prey range in laboratory studies, in the field it shows a strong preference for whiteflies. However, it is only effective as a natural enemy within high prey densities. In contrast, E. haitiensis is most effective when whitefly populations are low (Kumashiro et al., 1983).
Means of Movement and Dispersal
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Movement in Trade
The eggs and larvae of A. dispersus may be transported on leaves, and these early insect stages are often cryptic. The eggs may also be transported on fruit. Newly-dead foliage may harbour puparia, which are usually detected by the presence of woolly secretions.
The eggs and larvae of A. dispersus may be transported on leaves, and these early insect stages are often cryptic. The eggs may also be transported on fruit. Newly-dead foliage may harbour puparia, which are usually detected by the presence of woolly secretions.
Pathway Vectors
Top of page| Vector | Notes | Long Distance | Local | References |
|---|---|---|---|---|
| Clothing, footwear and possessions | Air travel with viable plant material | Yes |
Plant Trade
Top of page| Plant parts liable to carry the pest in trade/transport | Pest stages | Borne internally | Borne externally | Visibility of pest or symptoms |
|---|---|---|---|---|
| Fruits (inc. pods) | eggs | Yes | ||
| Leaves | eggs; larvae | Yes |
| Plant parts not known to carry the pest in trade/transport |
|---|
| Bark |
| Bulbs/Tubers/Corms/Rhizomes |
| Flowers/Inflorescences/Cones/Calyx |
| Growing medium accompanying plants |
| Roots |
| Stems (above ground)/Shoots/Trunks/Branches |
| True seeds (inc. grain) |
| Wood |
Wood Packaging
Top of page| Wood Packaging not known to carry the pest in trade/transport |
|---|
| Loose wood packing material |
| Non-wood |
| Processed or treated wood |
| Solid wood packing material with bark |
| Solid wood packing material without bark |
Impact Summary
Top of page| Category | Impact |
|---|---|
| Animal/plant collections | Negative |
| Animal/plant products | Negative |
| Biodiversity (generally) | None |
| Crop production | Negative |
| Environment (generally) | Negative |
| Fisheries / aquaculture | None |
| Forestry production | None |
| Human health | Negative |
| Livestock production | None |
| Native fauna | None |
| Native flora | Negative |
| Rare/protected species | None |
| Tourism | Negative |
| Trade/international relations | Negative |
| Transport/travel | None |
Impact
Top of page
The economic impact of A. dispersus infestations is due to a combination of three factors. Direct feeding damage results from the extraction of sap from leaves, mainly by larval stages but with adults also contributing. Direct feeding can cause premature leaf drop, reduces plant vigour and yields, but rarely kills plants outright. Indirect damage is due to excreted honeydew that encourages the development of sooty moulds, which hinder photosynthesis and reduce yields. Finally, cosmetic damage is due both to sooty moulds and to the white flocculence secreted by immature stages, which reduces the market-value of crops. Wind-borne flocculence can be unsightly, and may also contribute to asthma attacks (Waterhouse and Norris, 1989).
A. dispersus is not usually an economic pest within its native range of Central America and the Caribbean. In Florida, USA, where A. dispersus has been collected from avocados, citrus, guavas and palms, it was initially suspected of being a vector of the mycoplasma causing coconut lethal yellowing disease (Russell, 1965). Lethal yellows was first recorded a short time after A. dispersus became established, and has in the past been responsible for the loss of over 90% of the coconut palms in the Florida Keys (Russell, 1965; Weems, 1971). However, a planthopper is now suspected of being the lethal yellowing disease vector (Waterhouse and Norris, 1989). A. dispersus is currently only a minor pest in Florida.
In regions where A. dispersus has established in the absence of its natural enemies, however, it can be a serious pest of many horticultural crops, vegetable crops, ornamentals, fruit trees and shade trees. A. dispersus was first recorded in Hawaii in 1978, for example, and a year later it was considered to be a major economic pest of a diverse range of crops. Successful biological programs have been in operation in Hawaii since the early 1980s (Kumashiro et al., 1983).
A. dispersus is a recently discovered economic pest in both southern India and west Africa. In India, for example, it has reached pest status on cassava, where up to 580 insects per leaf have been observed (Palaniswami et al., 1995). A range of susceptible crops has been catalogued in Kerala, India, by Ranjith et al. (1996) and in Nigeria by Akinlosotu et al. (1993). It has also recently been recorded on soyabean in Indonesia, where it is a potential economic pest (Kajita et al., 1991). Since its accidental introduction into Taiwan in 1988, it has posed a serious threat to fruit trees, forest trees, food crops, ornamentals and shade trees throughout the country (Wen et al., 1997). A. dispersus currently presents a major threat to Australian agriculture, as it has recently entered Queensland via the Torres Strait islands (Lambkin, 1998).
A. dispersus is not usually an economic pest within its native range of Central America and the Caribbean. In Florida, USA, where A. dispersus has been collected from avocados, citrus, guavas and palms, it was initially suspected of being a vector of the mycoplasma causing coconut lethal yellowing disease (Russell, 1965). Lethal yellows was first recorded a short time after A. dispersus became established, and has in the past been responsible for the loss of over 90% of the coconut palms in the Florida Keys (Russell, 1965; Weems, 1971). However, a planthopper is now suspected of being the lethal yellowing disease vector (Waterhouse and Norris, 1989). A. dispersus is currently only a minor pest in Florida.
In regions where A. dispersus has established in the absence of its natural enemies, however, it can be a serious pest of many horticultural crops, vegetable crops, ornamentals, fruit trees and shade trees. A. dispersus was first recorded in Hawaii in 1978, for example, and a year later it was considered to be a major economic pest of a diverse range of crops. Successful biological programs have been in operation in Hawaii since the early 1980s (Kumashiro et al., 1983).
A. dispersus is a recently discovered economic pest in both southern India and west Africa. In India, for example, it has reached pest status on cassava, where up to 580 insects per leaf have been observed (Palaniswami et al., 1995). A range of susceptible crops has been catalogued in Kerala, India, by Ranjith et al. (1996) and in Nigeria by Akinlosotu et al. (1993). It has also recently been recorded on soyabean in Indonesia, where it is a potential economic pest (Kajita et al., 1991). Since its accidental introduction into Taiwan in 1988, it has posed a serious threat to fruit trees, forest trees, food crops, ornamentals and shade trees throughout the country (Wen et al., 1997). A. dispersus currently presents a major threat to Australian agriculture, as it has recently entered Queensland via the Torres Strait islands (Lambkin, 1998).
Detection and Inspection
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When A. dispersus are abundant they are conspicuous on leaves due to the white flocculence that covers their bodies (Russell, 1965). They are found on the undersides of leaves, often associated with sticky honeydew and sometimes sooty mould growth.
A. dispersus were found in significantly higher numbers in the upper canopy than in the middle and the lower canopy on guava (Shah Alam et al., 1997).
A. dispersus were found in significantly higher numbers in the upper canopy than in the middle and the lower canopy on guava (Shah Alam et al., 1997).
Similarities to Other Species/Conditions
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Russell (1965) described A. dispersus in comparison with the closely related A. coccolobae and A. flavus. Identification is on the basis of distinctive compound and simple pores in the pupal stage. It should be noted that other members of this genus, mostly native to the Neotropical region, also lay their eggs in spiral patterns like A. dispersus. Reliable identification requires microscopic study of slide-mounted pupal cases.
Martin et al. (1997) provided keys to enable adults and puparia of A. dispersus to be distinguished from the newly introduced crop pest Lecanoideus floccissimus sp. nov. in the Canary Islands.
Martin et al. (1997) provided keys to enable adults and puparia of A. dispersus to be distinguished from the newly introduced crop pest Lecanoideus floccissimus sp. nov. in the Canary Islands.
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.
Biological ControlA. dispersus was first recorded in Hawaii in 1978, after which it spread rapidly. Its pest status on guavas stimulated a successful biological control programme (Kumashiro et al., 1983; Beardsley, 1992). The introduction and establishment of the coccinellid beetle Nephaspis oculatus (N. amnicola) and the parasitoid Encarsia haitiensis successfully controlled A. dispersus on guavas in highland and lowland areas of Honolulu, Hawaii. In 1980-81, peak population densities of A. dispersus were reduced by 79% in the lowlands and 98.8% in the highlands. Rainfall, temperature and previously established predators, particularly Allograpta obliqua, probably also contributed to the reduction of A. dispersus populations (Kumashiro et al., 1983).
Since the biological control of A. dispersus in Hawaii, there have been further successes on Pacific Islands; for a review see Waterhouse and Norris (1989). In each case, Encarsia haitiensis was successful, aided by one or more of the introduced coccinellids.
A biological programme in Tropical Africa was described by Neuenschwander (1996), in which two exotic hymenopterous parasitoids were introduced. These helped control A. dispersus populations, with indigenous coccinellids playing a minor role. A. dispersus was observed in Benin for the first time in 1993, along with the parasitoids Encarsia ?haitiensis and E. guadeloupae, which were thought to have been accidentally introduced. Between 1993 and 1996, these parasitoids helped control A. dispersus populations on guava (D'Almeida et al., 1998). E. haitiensis has been successfully introduced into Queensland, as part of the biological control of A. dispersus in Australia (Lambkin, 1998).
Chemical Control
Kajita et al. (1991) described some insecticides effective against A. dispersus on soyabeans in Indonesia. However, because the whitefly has such a wide host-plant range, and insecticides also impact natural enemies, chemical control is usually considered impractical and uneconomic in the long-term (Kajita et al., 1991; Lambkin, 1998). Laprade and Cerdas (1998) evaluated insecticide treatments on banana farms in Costa Rica. Dilute aqueous solutions of soaps and detergents have also provided effective control in smallholdings, in conjunction with pruning and mulching, the latter to counter moisture loss by plants due to infestation (Anon., 1980).
References
Top of pageAnon., 1980. Bio-control of the Spiraling whitefly. Biological Control Section, Plant Pest Control Branch, Department of Agriculture, Honolulu, Hawaii.
APPPC, 1987. Insect pests of economic significance affecting major crops of the countries in Asia and the Pacific region. Technical Document No. 135. Bangkok, Thailand: Regional Office for Asia and the Pacific region (RAPA).
AVA, 2001. Diagnostic records of the Plant Health Diagnostic Services, Plant Health Centre, Agri-food & Veterinary Authority, Singapore.
Beardsley JW, 1992. Exotic terrestrial arthropods in the Hawaiian Islands: origins and impacts. Biological Control of Exotic Pests in the Pacific. Proceedings of a Plenary Session and Symposium, XIX International Congress of Entomology, Beijing, June 1992. Micronesica. 1993, No. 4 supplement, 11-15.
Blanco Metzler H, Laprade S, 1998. Enemigos naturales de la mosca blanca Aleurodicus dispersus Russell (Homoptera: Aleyrodidae): parasitoides y depredadores. [Natural enemies of the spiralling whitefly, Aleurodicus dispersus Russell (Homoptera: Aleyrodidae): Parasitoids and predators]. Agronomia Mesoamericana, 9(2):41-44.
EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization. http://www.eppo.int/DATABASES/pqr/pqr.htm
Ganeshan S, 2000. First occurrence of: Aleurodicus dispersus (Russell). EWSN Newsletter No. 6., p.4.
Gerling D, 1990. Natural enemies of whiteflies: predators and parasitoids. In: Gerling D, ed. Whiteflies: Their Bionomics, Pest Status and Management. UK: Intercept Ltd., 147-185.
Hernandez-Suarez E, Carnero A, Aguiar A, Prinsloo G, LaSalle J, Polaszek A, 2003. Parasitoids of whiteflies (Hymenoptera: Aphelinidae, Eulophidae, Platygastridae; Hemiptera: Aleyrodidae) from the Macaronesian archipelagos of the Canary Islands, Madeira and the Azores. Systematics and Biodiversity, 1(1):55-108.
IIE, 1993. Distribution Maps of Plant Pests, No. 476. Wallingford, UK: CAB International.
Lambkin T, 1998. Spiraling whitefly threat to Australia. Quarantine Bulletin no. 8. Department of Primary Industry, Brisbane, Queensland, Australia.
Laprade S, Cerdas VH, 1998. Manejo de mosca blanca (Aleurodicus dispersus Russell, Homoptera: Aleyrodidae) en banano (Musa AAA) utilizando insecticidas y aceite. [Management of the spiralling white fly (Aleurodicus dispersus Russell, Homoptera: Aleyrodidae) in banana (Musa AAA) using insecticides and oil]. CORBANA, 22(48):89-94.
Martin JH, 1990. The whitefly pest specis Aleurodicus dispersus and its rapid extension of range across the Pacific and South-East Asia. MAPPS Newsletter, 14(3):36.
Monteiro AHRR, Gomes S, Gomes I, Queiroz PR, Lima LHC, Oliveira MRV, 2005. .
Polaszek A, Shahab-Manzari, Quicke DLJ, 2004. Morphological and molecular taxonomic analysis of the Encarsia meritoria species-complex (Hymenoptera, Aphelinidae), parasitoids of whiteflies (Hemiptera, Aleyrodidae) of economic importance. Zoologica Scripta, 33(5):403-421.
Russell LM, 1965. A new species of Aleurodicus Douglas and two close relatives (Homoptera: Aleyrodidae). The Florida Entomologist, 48:47-55.
Watson GW, Ooi PAC, Girling DJ, 1995. Insects on plants in the Maldives and their management. Ascot, UK: International Institute of Biological Control.
Distribution References
CABI, Undated. Compendium record. Wallingford, UK: CABI
CABI, Undated a. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI
Ganeshan S, 2000. First occurrence of: Aleurodicus dispersus (Russell). In: EWSN Newsletter, 6 4.
NHM, Undated. Specimen record from the collection in the Natural History Museum (London, UK)., London, UK: Natural History Museum (London).
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