Trialeurodes ricini (castor bean whitefly)
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Distribution Table
- Risk of Introduction
- Hosts/Species Affected
- Host Plants and Other Plants Affected
- Growth Stages
- List of Symptoms/Signs
- Biology and Ecology
- Natural enemies
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Plant Trade
- Wood Packaging
- Detection and Inspection
- Similarities to Other Species/Conditions
- Prevention and Control
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Trialeurodes ricini (Misra)
Preferred Common Name
- castor bean whitefly
Other Scientific Names
- Aleyrodes ricini Misra
- Trialeurodes desmodii Corbett
- Trialeurodes lubia El Khidir & Khalifa
- Trialeurodes rara Singh
International Common Names
- English: castor whitefly
Local Common Names
- India: castor mealy wing
- TRIADE (Trialeurodes rara)
- TRIARI (Trialeurodes ricini)
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Arthropoda
- Subphylum: Uniramia
- Class: Insecta
- Order: Hemiptera
- Suborder: Sternorrhyncha
- Unknown: Aleyrodoidea
- Family: Aleyrodidae
- Genus: Trialeurodes
- Species: Trialeurodes ricini
Notes on Taxonomy and NomenclatureTop of page
This whitefly was first fully described from specimens on Ricinus communis (castor bean) in India (Misra, 1924), although by then it had already been known for some years. The generic and specific classification of whiteflies is usually based upon pupal morphology. However, the morphology of the pupal stage can vary according to the host, hence this is a phenotypically variable species. Molecular studies are required to assist in clarifying the systematics of the group.
The taxonomic relationship between Trialeurodes ricini and Trialeurodes lauri was recently investigated using morphological and molecular data (Malumphy et al., 2007) . Molecular evidence, based on the sequence of a fragment of the COI gene, supported the hypothesis that T. ricini and T. lauri are distinct valid species.
DescriptionTop of page
Whitish-green with a smooth surface; oblong; approximately 0.2 mm long and 0.08 mm wide at the widest point; tapering at one end.
Greenish-yellow with red eyes; elliptical. The first-instar larvae are approximately 0.26 mm long by 0.13 mm wide, and slightly convex with a waxy fringe. The second-instar larvae are approximately 0.33 mm to 0.41 mm long and 0.19 mm to 0.25 mm wide, with a narrow waxy band. The third-instars are 0.48 mm to 0.51 mm long and 0.30 mm to 0.38 mm wide.
Yellow with red eyes; white waxy filaments at the margins; elliptical, thin and flat, but becoming thicker after 3 or 4 days. The female pupae are approximately 0.67 mm to 0.75 mm long and 0.39 mm to 0.60 mm wide. The males are much smaller: between 0.57 mm and 0.66 mm long, and 0.31 mm to 0.43 mm wide. The physical characteristics of the host leaf surface induce variation in the morphology of the puparia.
Shishehbor (1994) provides illustrations of the first-, second- and third-instar larvae, as well as the pupa.
Bright-yellow to cream body, with white legs and wings. At rest the wings are held 'tent-like', at an angle over the body.
DistributionTop of page T. ricini is widely distributed within Africa, the Middle East and Asia. T. ricini has been intercepted by the National Plant Protection Organisation of the UK on plant material from Cameroon (EPPO, 2000).
Distribution TableTop of page
The 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.
Risk of IntroductionTop of page T. ricini was added to the Alert List of the European and Mediterranean Plant Protection Organisation (EPPO) in April 2000 as a result of its spread and establishment in the Canary Isles (Anon., 2000). This organism presents a risk mainly to tropical and sub-tropical regions. In warm countries, where this organism does not occur, the outdoor cultivation of crops such as castor bean (Ricinus communis), cotton (Gossypium spp.), pumpkin (Cucurbita spp.), sweet potato (Ipomoea batatas), potato (Solanum tuberosum), melon (Cucumis melo) and French beans (Phaseolus vulgaris) are primarily at risk. Although it has not been reported from protected cultivation, this organism could be a threat to crops such as cucumbers (Cucumis sativus), tomatoes (Lycopersicon esculentum), and aubergines (Solanum melongena) grown in heated glasshouses in cooler countries.
HabitatTop of page T. ricini is most commonly recorded from managed crop habitats, usually being recorded on castor (Ricinus communis).
Hosts/Species AffectedTop of page T. ricini is highly polyphagous, and feeds on hosts in at least thirteen plant families. The complete range of hosts could be greater than that provided in this datasheet, because T. ricini may be able to adapt to feed on other hosts as it expands its geographic distribution.
Host Plants and Other Plants AffectedTop of page
Growth StagesTop of page Flowering stage, Fruiting stage, Vegetative growing stage
SymptomsTop of page Infested hosts may show symptoms such as honeydew deposits, leading to the development of sooty mould, and leaf browning and withering.
List of Symptoms/SignsTop of page
|Leaves / honeydew or sooty mould|
|Leaves / wilting|
|Leaves / yellowed or dead|
|Whole plant / external feeding|
Biology and EcologyTop of page As with other whitefly species, the eggs are laid on the under surface of leaves (Nair, 1986) and form small clusters. In India, the eggs can be found from the beginning of February (Misra, 1924). This is a pest with a high threshold temperature for development and the climate in India has an important influence on population development (David et al., 1973). The eggs require a minimum of 17°C for development. The optimum temperature for development is 30°C (Shishehbor and Brennan, 1995). After hatching, a first-instar larva, which is the only mobile juvenile stage, will walk a short distance to find a suitable feeding location on the underside of the leaf on which it hatched. The stylet mouthparts pierce plant tissue and the larva feeds by sucking phloem sap. The larva has four instars (Nair, 1986). The second-, third- and fourth-instars are sessile. The adults emerge from the final larval stage called the puparium. The adults are active during the day and become torpid during cold evenings (Nair, 1986). In northern India, this pest can be seen on leaves between February and November. From July to September, the life cycle in India is completed in 19 to 21 days (Nair, 1986). There are overlapping generations.
Shishehbor and Brennan (1996a) conducted laboratory studies and measured development time from egg to adult on five hosts at fluctuating temperatures (day 25°C, night 17°C). Development on aubergine (Solanum melongena) took 18 days from egg to adult with 72% survival; on cotton (Gossypium spp.) development took 18 days (68% survival); on French beans (Phaseolus vulgaris), 21 days (58% survival); on potato (Solanum tuberosum), 20 days (41% survival); and on pumpkin (Cucurbita spp.), 30 days (59% survival). During September, under field conditions in northern India, the life cycle is completed in 19 to 21 days (Nair, 1986). In the field, El Khidir and Khalifa (1962) noted that adults lay an average of 100 eggs. However, in laboratory trials at 20°C, the females laid an average of 183 eggs, at 25°C an average of 224 eggs were laid, at 30°C an average of 294 eggs were laid and at 35°C an average of 132 eggs were laid (Shishehbor and Brennan, 1996b). Such data suggest that population development is optimal at temperatures between 25 and 30°C.
Natural enemiesTop of page
|Natural enemy||Type||Life stages||Specificity||References||Biological control in||Biological control on|
Notes on Natural EnemiesTop of page Encarsia formosa is a parasite of T. ricini, and may be used as a biological control agent (Shishehbor and Brennan, 1996c, d).
Means of Movement and DispersalTop of page Natural Dispersal (Non-Biotic)
The adults are weak flyers and can disperse naturally.
T. ricini was not known to be a virus vector until Idriss et al. (1997) reported it as a vector of tomato yellow leaf curl virus (TYLCV) in Egypt. Idriss et al. (1997) reports that there are a number of biotypes, each of which is viruliferous. In a review of whitefly-transmitted viruses, Jones (2003) includes T. ricini as a vector of TYLCV, but points out that transmission studies in the UK have not confirmed that T. ricini is indeed a vector. Nelson et al. (2004) used a T. ricini population from the Canary Isles and conducted virus transmission experiments on beans, tomatoes and other hosts. Working with TYLCV and other viruses, they were not able to demonstrate virus transmission. There may be genetic differences between populations of T. ricini in Egypt and the Canary Isles causing differences in the ability to transmit viruses.
The movement of infested plants or fruits can lead to long-distance spread.
Movement in Trade
The UK has found this pest during phytosanitary inspections of vegetables from Africa (Anon., 2003) indicating that this whitefly can spread in trade. Spread can occur via infected plants for planting, vegetables and fruits from countries where T. ricini is present. T. ricini has been found in the Canary Isles (Anon., 2000). Since there are strong transport and trading links between the Canary Isles and Spain and the rest of Europe, there is a good chance of further spread.
Plant TradeTop of page
|Plant parts liable to carry the pest in trade/transport||Pest stages||Borne internally||Borne externally||Visibility of pest or symptoms|
|Leaves||adults; eggs; larvae; pupae||Yes||Pest or symptoms usually visible to the naked eye|
|Plant parts not known to carry the pest in trade/transport|
|Fruits (inc. pods)|
|Growing medium accompanying plants|
|Stems (above ground)/Shoots/Trunks/Branches|
|True seeds (inc. grain)|
Wood PackagingTop of page
|Wood Packaging not known to carry the pest in trade/transport|
|Loose wood packing material|
|Processed or treated wood|
|Solid wood packing material with bark|
|Solid wood packing material without bark|
ImpactTop of page T. ricini is a serious pest of castor (Ricinus communis) in tropical regions of Africa and Asia (Mound and Halsey, 1978; Bink-Moenen, 1983; Vora et al., 1984; Abd-Rabou et al., 2000). It has been regarded as a minor pest in southern provinces of Iran (Farahbakhsh, 1961) and is a minor pest of hyacinth bean (Lablab purpureus) and sapodilla (Manilkara zapota) in India (Hill, 1983). The larvae and adults suck sap from lower leaf surfaces and the resulting honeydew deposits lead to the development of sooty moulds. Heavy infestations can produce a large amount of honeydew and sooty moulds can cause a significant reduction in photosynthesis, which reduces plant growth. Seed yield may be reduced in castor due to sooty moulds (Patel et al., 1986). An excessive loss of sap, due to heavy infestations, reduces host vigour.
Many field vegetable crops can also be attacked. In Egypt, T. ricini occurs in all governates on many different crops in huge numbers during the summer (Idriss et al., 1997) and, with other whitefly species, can cause heavy losses.
Detection and InspectionTop of page Hosts showing symptoms such as growth of sooty mould or leaf browning or withering should be inspected. The adults can be seen when they flutter from the underside of leaves when a plant is disturbed. The underside of leaves should be closely visually examined for immature life stages.
Similarities to Other Species/ConditionsTop of page It is difficult to identify this organism; it may be confused with the glasshouse whitefly, Trialeurodes vaporariorum. T. ricini may be the senior synonym of Trialeurodes lauri, a native Mediterranean species, present in France, Greece, Italy, Turkey and the former Yugoslavia (Martin et al., 2000).
Prevention and ControlTop of page
Given suitable conditions, populations can rapidly grow. In India, dimethoate and quinalphos, both at 0.05%, are recommended for controlling T. ricini on castor bean (Ricinus communis) (Patel et al., 1986). Spays should be applied carefully because individuals inhabit the underside of leaves, which can provide some protection from chemical spray treatments.
ReferencesTop of page
Abd-Rabou S; Hussein N; Sewify GH; Elnagar S, 2000. Seasonal abundance of the whitefly Trialeurodes ricini (Misra) (Homoptera: Aleyrodidae) on some weeds and on castor plants in Qalyubia, Egypt. Bulletin of Faculty of Agriculture, University of Cairo, 51(4):501-510; 6 ref.
Anon, 2000. Canary Islands results. European Whitefly Studies Network Newsletter, No. 3.
Anon, 2003. Plant Health Interception and Outbreak Chart 6 December 2003. Department of Environment, Food and Rural Affairs. http://www.defra.gov.uk/planth/interc/6dec03.pdf.
AVA, 2001. Diagnostic records of the Plant Health Diagnostic Services, Plant Health Centre, Agri-food & Veterinary Authority, Singapore.
Bink-Moenen RM, 1983. Revision of the African whiteflies (Aleyrodidae), mainly based on a collection from Tchad. Revision of the African whiteflies (Aleyrodidae), mainly based on a collection from Tchad. Nederlandse Entomologische Vereniging Amsterdam Netherlands, 210 pp.
Corbett GH, 1935. On new Aleyrodidae (Hem.). Annals of the Magazine of Natural History, 10(16):240-252.
El Khidir E; Khalifa A, 1962. A new aleyrodid from the Sudan. Proceedings of the Royal Entomological Society of London, Series B, 31:47-51.
EPPO, 2000. Additions to the EPPO Alert List, Trialeurodes ricini (Homoptera: Aleyrodidae) - Castor whitefly, EPPO Reporting Service, 2000, No. 4.
EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization. http://www.eppo.int/DATABASES/pqr/pqr.htm
Farahbakhsh G, 1961. A Checklist of Economically Important Insects and other Enemies of Plants and Agricultural Products in Iran. Tehran, Iran: Department of Plant Protection, Ministry of Agriculture.
Idriss M; Abdallah N; Aref N; Haridy G; Madkour M, 1997. Biotypes of the castor bean whitefly Trialeurodes ricini (Misra) (Hom., Aleyrodidae) in Egypt: biochemical characterization and efficiency of geminivirus transmission. Journal of Applied Entomology, 121(9/10):501-509; 43 ref.
Lourens JH; Brader L; van der Laan PA, 1972. Contribution à l’étude d’une ‘mosaïque’ du cotonnier au Tchad; distribution dans un champ; Aleurodidae communs; essais de transmission de cotonnier à cotonnier par les Aleurodidae. Coton et Fibres Tropicales, 27(2):225-230.
Malumphy C; Suarez MB; Glover R; Boonham N; Collins DW, 2007. Morphological and molecular evidence supporting the validity of Trialeurodes lauri and T. ricini (Hemiptera: Sternorrhyncha: Aleyrodidae). European Journal of Entomology, 104(2):295-301. http://www.eje.cz/scripts/content.php
Martin JH, 1987. An identification guide to common whitefly pest species of the world (Homoptera: Aleyrodidae). Tropical Pest Management, 33:298-322.
Misra CS, 1924. The citrus whitefly, Dialeurodes citri in India and its parasite, together with the life history of Aleurodes ricini, n. sp. Report of Proceedings of an Entomological Meeting, Pusa 1923:129-135.
Muniappan R; Watson GW; Vaughan L; Gilbertson R; Noussourou M, 2012. New records of mealybugs, scale insects, and whiteflies (Hemiptera: Sternorrhyncha) from Mali and Senegal. Journal of Agricultural and Urban Entomology, 28(1):1-7. http://scentsoc.org/Volumes/JAUE/28/28001.pdf
Nelson D; Hatt G; Nelson C; Bedford ID, 2004. Trialeurodes ricini (Misra): A begomovirus vector? In: Proceedings of the 2nd European Whitefly Studies Network Symposium, Cavtat, Croatia, 5-9 October, 2004.
Parviz Shishehbor; Brennan PA, 1995. Environmental effects on pre-imaginal development and survival of the castor whitefly, Trialeurodes ricini Misra. Insect Science and its Application, 16(3/4):325-331; 24 ref.
Patel MM; Naik MM; Vyas HN; Patel AT, 1986. Evaluation of certain insecticides against whitefly (Trialeurodes ricini Misra) and jassid (Empoasca kerri Pruthi) infesting castor. Indian Journal of Plant Protection, 14(1):81-82
Shishehbor P, 1994. Investigations on the morphology, biology and ecology of the castor whitefly, Trialeurodes ricini Misra (Homoptera: Aleyrodidae). PhD Thesis. Ireland: University of Dublin.
Shishehbor P; Brennan PA, 1996. Adult longevity, fecundity, and population growth rates for Trialeurodes ricini Misra (Homoptera: Aleyrodidae) at different constant temperatures. Canadian Entomologist, 128(5):859-863; 19 ref.
Shishehbor P; Brennan PA, 1996. Functional response of Encarsia formosa (Gahan) parasitizing castor whitefly, Trialeurodes ricini Misra (Hom., Aleyrodidae). Journal of Applied Entomology, 120(5):297-299; 14 ref.
Shishehbor P; Brennan PA, 1996. Life history traits of castor whitefly, Trialeurodes ricini Misra (Hom., Aleyrodidae), on eight host plant species. Journal of Applied Entomology, 120(9):519-522; 21 ref.
Shishehbor P; Brennan PA, 1996. Parasitism of the castor whitefly, Trialeurodes ricini (Homoptera: Aleyrodidae) by Encarsia formosa (Hymenoptera: Aphelinidae): bionomics in relation to temperature. Bulletin of Entomological Research, 86(1):67-72; 34 ref.
Waterhouse DF, 1993. The Major Arthropod Pests and Weeds of Agriculture in Southeast Asia. ACIAR Monograph No. 21. Canberra, Australia: Australian Centre for International Agricultural Research, 141 pp.
Distribution MapsTop of page
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