Dialeurodes citri (citrus 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
- Impact
- Diagnosis
- Detection and Inspection
- Similarities to Other Species/Conditions
- Prevention and Control
- References
- Distribution Maps
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Generate reportIdentity
Top of pagePreferred Scientific Name
- Dialeurodes citri (Ashmead, 1885)
Preferred Common Name
- citrus whitefly
Other Scientific Names
- Aleurodes eugeniae var. aurantii Maskell, 1895
- Aleyrodes (Dialeurodes) citri (Riley & Howard) Cockerell, 1902
- Aleyrodes aurantii (Maskell) Cockerell, 1903
- Aleyrodes citri Ashmead, 1885
- Aleyrodes citri Riley & Howard, 1893
- Aleyrodes kushinasii Sasaki, 1908
- Dialeurodes citri (Ashmead) Quaintance & Baker, 1916
- Dialeurodes citri (Ashmead) var. hederae Takahashi, 1936
- Dialeurodes citri (Ashmead) var. kinyana Takahashi, 1935
- Dialeurodes tuberculatus Takahashi, 1932
International Common Names
- Spanish: mosca blanca del citrico
- French: aleurode des aurantiacees; aleurode du citronnier
Local Common Names
- Germany: Mottenschildlaus, Zitrus-; Weisse Fliege
- Italy: dialeurode degli agrumi
- Japan: mikan-konazorami
EPPO code
- DIALCI (Dialeurodes citri)
Taxonomic Tree
Top of page- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Arthropoda
- Subphylum: Uniramia
- Class: Insecta
- Order: Hemiptera
- Suborder: Sternorrhyncha
- Unknown: Aleyrodoidea
- Family: Aleyrodidae
- Genus: Dialeurodes
- Species: Dialeurodes citri
Notes on Taxonomy and Nomenclature
Top of pageDescription
Top of pageEgg
The egg of D. citri is elongated, elliptical, tapered and almost pointed in the anterior part and is posteriorly provided with a stalk. It is creamy-yellow, 0.24-0.27 mm long (without stalk) and 0.09-0.12 mm wide (greater in the distal third).
Nymphs
Nymphal stages are sub-elliptical in shape and almost flattened; they can be easily mistaken for young scale insects, but they have a well-marked vasiform orifice.
First instar: Creamy-yellow, 0.27-0.34 mm long and 0.16-0.21 mm wide. The margin has 14-17 pairs of setae, in addition to the anterior, posterior and caudal ones. The vasiform orifice is almost triangular, and is almost completely covered by the subcordate operculum. The lingula is concealed. Antennae and legs are well developed.
Second instar: Colour and shape similar to the first instar, 0.45-0.55 mm long and 0.30-0.36 mm wide. The margin has only the anterior, posterior and caudal pairs of setae. The vasiform orifice is almost rounded, slightly thickened in its margin and completely covered by the operculum. The antennae and legs are reduced. Tracheal folds are evident.
Third instar: Very similar to the second instar but larger; length 0.62-0.82 mm, width 0.43-0.63 mm.
Fourth instar (pupal case): Colourless or yellowish, oval to broadly oval. Often slightly constricted just posteriorly of thoracic tracheal pores. Body length is 1.00-1.50 mm, and width is 0.60-1.20 mm. The margin is finely crenellated, with well-marked and rounded (10-16 µm in diameter) tracheal pores. The cephalic, eighth abdominal and caudal setae are minute, the first abdominal setae are 'wanting'. Eleven pairs of minute setae are present in a submarginal-subdorsal position. Tubercle clusters are often present on the submedial area, usually on the prothorax, metathorax and the second abdominal segment. The vasiform orifice is relatively small (45-60 µm long), subcircular and with a broad rim, and has toothed posterior and lateral inner margins. The operculum almost fills the vasiform orifice, concealing the tip of the lingula. The ventral region has tracheal folds (both thoracic and abdominal) densely set with microtubercles. According to Benmessaoud-Boukhalfa (1991), slight morphological differences exist between summer and winter pupal cases, mainly pertaining to the dorsal surface and the vasiform orifice. This is the stage used for identification purposes.
Adult
The body is creamy-yellow, with white wings that are 0.75-1.10 mm long (hindwings) or 0.95-1.35 mm long (forewings). The compound eyes are well developed, each one divided in two connected parts. The antennae are seven segmented. Forewings have veins reduced to C+Sc, R and a small Cu. The vasiform orifice is almost circular, partly covered by a transverse, subrectangular operculum. The lingula is posteriorly tapered, with an elongated and parallel-sided distal portion.
Distribution
Top of pageDistribution 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: 12 May 2022Continent/Country/Region | Distribution | Last Reported | Origin | First Reported | Invasive | Reference | Notes |
---|---|---|---|---|---|---|---|
Africa |
|||||||
Algeria | Present | ||||||
Egypt | Present | ||||||
Morocco | Present | ||||||
Nigeria | Present | ||||||
Tunisia | Present | ||||||
Asia |
|||||||
Afghanistan | Present | ||||||
Azerbaijan | Present | ||||||
Bangladesh | Present | ||||||
China | Present | ||||||
-Fujian | Present | ||||||
-Guangdong | Present | ||||||
-Hainan | Present | ||||||
-Hebei | Present | ||||||
-Henan | Present | ||||||
-Hubei | Present | ||||||
-Hunan | Present | ||||||
-Jiangsu | Present | ||||||
-Sichuan | Present | ||||||
-Yunnan | Present | ||||||
-Zhejiang | Present | ||||||
Georgia | Present | ||||||
Hong Kong | Present | ||||||
India | Present | ||||||
-Andhra Pradesh | Present | ||||||
-Assam | Present | ||||||
-Bihar | Present | ||||||
-Delhi | Present | ||||||
-Himachal Pradesh | Present | ||||||
-Karnataka | Present | ||||||
-Kerala | Present | ||||||
-Madhya Pradesh | Present | ||||||
-Maharashtra | Present | ||||||
-Odisha | Present | ||||||
-Punjab | Present | ||||||
-Sikkim | Present | ||||||
-Tamil Nadu | Present | ||||||
-Uttar Pradesh | Present | ||||||
-West Bengal | Present | ||||||
Israel | Present | ||||||
Japan | Present | ||||||
-Honshu | Present | ||||||
-Kyushu | Present | ||||||
-Shikoku | Present | ||||||
Lebanon | Present | First reported: 198* | |||||
Macau | Present | ||||||
Pakistan | Present | ||||||
South Korea | Present | ||||||
Sri Lanka | Present | ||||||
Taiwan | Present | ||||||
Tajikistan | Present | ||||||
Thailand | Present | ||||||
Turkey | Present | ||||||
Uzbekistan | Present | ||||||
Vietnam | Present | ||||||
Europe |
|||||||
Albania | Present | Introduced | 1970 | ||||
Croatia | Present, Localized | ||||||
Cyprus | Absent, Unconfirmed presence record(s) | ||||||
France | Present, Localized | ||||||
-Corsica | Present | Introduced | 2004 | ||||
Greece | Present | ||||||
-Crete | Present | ||||||
Italy | Present | Introduced | 1962 | ||||
-Sardinia | Present | ||||||
-Sicily | Present | ||||||
Malta | Present | ||||||
Montenegro | Present | ||||||
Russia | Present, Localized | ||||||
-Southern Russia | Present | ||||||
Spain | Present, Localized | ||||||
-Canary Islands | Present | ||||||
United Kingdom | Absent, Intercepted only | ||||||
North America |
|||||||
Bahamas | Present | ||||||
Barbados | Present | ||||||
Bermuda | Present | ||||||
Costa Rica | Present | ||||||
Cuba | Present | ||||||
El Salvador | Present | ||||||
Guatemala | Present | ||||||
Mexico | Present, Localized | ||||||
Puerto Rico | Present | ||||||
United States | Present, Widespread | ||||||
-Alabama | Present | ||||||
-California | Present | ||||||
-Colorado | Present | ||||||
-Florida | Present | ||||||
-Georgia | Present | ||||||
-Illinois | Present | ||||||
-Louisiana | Present | ||||||
-Mississippi | Present | ||||||
-North Carolina | Present | ||||||
-South Carolina | Present | ||||||
-Texas | Present | ||||||
-Virginia | Present | ||||||
-Washington | Present | ||||||
South America |
|||||||
Argentina | Present | ||||||
Brazil | Absent, Unconfirmed presence record(s) | ||||||
Chile | Present | ||||||
Colombia | Present | ||||||
Guyana | Present | ||||||
Peru | Present |
Risk of Introduction
Top of pageHosts/Species Affected
Top of pageHost Plants and Other Plants Affected
Top of pageSymptoms
Top of pageList of Symptoms/Signs
Top of pageSign | Life Stages | Type |
---|---|---|
Fruit / honeydew or sooty mould | ||
Inflorescence / honeydew or sooty mould | ||
Leaves / honeydew or sooty mould | ||
Stems / honeydew or sooty mould |
Biology and Ecology
Top of pageAdults of D. citri normally live for ca 10 days, but they can live for as long as 27 days. The female lays her pale yellow eggs scattered singly on the underside of leaves, particularly young ones. The eggs usually hatch in 8-24 days, depending on the season. The young nymphs move around for several hours, then they settle on the leaf underside. Nymphs become sedentary, and their legs become vestigial.
Natural enemies
Top of pageNatural enemy | Type | Life stages | Specificity | References | Biological control in | Biological control on |
---|---|---|---|---|---|---|
Aschersonia aleyrodes | Pathogen | Arthropods|Nymphs | ||||
Aschersonia aleyrodis | Pathogen | Adults; Arthropods|Nymphs | China; Fujian; China; Zhejiang; Cuba; USA; Florida | Citrus | ||
Aschersonia placenta | Pathogen | Adults; Arthropods|Nymphs | ||||
Beauveria bassiana | Pathogen | Adults; Arthropods|Nymphs | ||||
Clitostethus arcuatus | Predator | Adults; Arthropods|Nymphs | ||||
Delphastus pallidus | Predator | Adults; Arthropods|Nymphs | Cuba | Citrus | ||
Delphastus pusillus | Predator | Adults; Arthropods|Nymphs | USSR | |||
Encarsia abundantia | Parasite | |||||
Encarsia formosa | Parasite | Adults; Arthropods|Nymphs | France | Citrus | ||
Encarsia lahorensis | Parasite | Adults; Arthropods|Nymphs | California; China; Guangdong; Corfu; Florida; France; Greece; Israel; Italy; Italy; Sardinia; Republic of Georgia; Sicily; USA; Alabama; USSR; Uzbekistan; Russia; North Carolina | Citrus; Gardenia jasminoides | ||
Encarsia longifasciata | Parasite | |||||
Encarsia sophia | Parasite | |||||
Encarsia strenua | Parasite | |||||
Encarsia tricolor | Parasite | |||||
Eretmocerus eremicus | Parasite | Adults; Arthropods|Nymphs | ||||
Eretmocerus paulistus | Parasite | Adults; Arthropods|Nymphs | ||||
Euderomphale flavimedia | Parasite | |||||
Lecanicillium lecanii | Pathogen | Adults; Arthropods|Nymphs | ||||
Semidalis aleyrodiformis | ||||||
Serangium parcesetosum | Predator | Adults; Arthropods|Nymphs | Republic of Georgia; USSR | Citrus |
Notes on Natural Enemies
Top of pageThe fungal pathogen, Aschersonia is of major importance, especially in areas where the humidity is high. A. aleyrodis is the best known species among this group. In studies carried out in China (Shu-Zheng, 1996), this pathogen was shown to survive, grow and produce spores at 10-32°C (optimum 20-25°C); the temperature for the germination of conidia ranged from 5 to 30°C (optimum 20-30°C). The fungus grew at pH 3-10, although values ranging from 6 to 7 appeared to be optimal for mycelial growth and sporulation. In the field, A. aleyrodis survived 15 months (compared to 17 months at room temperature and 28 months at 0°C under laboratory conditions). Gao et al. (1985) state that this pathogen is highly effective in controlling D. citri in China. When branches infected with spores of the fungus were hung over trees infested by D. citri, the infection rate was 74% 8 months after treatment. A. placenta (which may be conspecific with A. aleyrodis) has been shown to attack nymphs (especially the second and third instars) of D. citri at a rate of 33-78% (Zou, 1988), and has been introduced in the former USSR, where in Adzharia it achieved up to 90% parasitism under favourable conditions (Ponomarenko et al., 1975).
Insect predators of D. citri belong to the Thysanoptera, Heteroptera, Neuroptera and the Coleoptera (including coccinellid beetles of the genera Clitosthethus, Delphastus and Serangium). Clitostethus arcuatus is a predator of D. citri and other similar species (Bemisia tabaci, Siphoninus phillyreae and Trialeurodes vaporariorum). In Italy, C. arcuatus has four generations per year (Loi, 1978; Liotta, 1981). In Sicily, the first generation occurs from mid-April to mid-May, the second in June, the third in July and the fourth from mid- or late-August to the end of September; adults overwinter in cracks in tree bark or in walls, but move into citrus orchards during mild sunny days. Studies carried out in the Republic of Georgia, record C. arcuatus as having only one generation per year (Agekyan, 1977; Loi, 1978). Each C. arcuatus female lays 11-41 eggs on the lower surface of Citrus leaves. Larvae hatch after 3-8 days and pupate after a further 8-24 days, dependent on the temperature. They mainly feed on eggs but also on nymphs of D. citri. Adults emerge 3-8 days after pupation. Another coccinellid species, Serangium parcesetosum, is probably native to India; but it has been introduced in several Citrus-growing areas for the biological control of D. citri, for example in southern France and Corsica (Malausa et al., 1988), during 1986-87, and the former Soviet Union (Timofeeva and Hoang, 1978). On the Black Sea coasts of the Caucasus, S. parcesetosum has four generations per year and destroys up to 90% of whitefly colonies. It passes the winter as adults, which congregate in masses in old leaves and beneath the bark of trees, and resume activity in early April (Timofeeva and Hoang, 1978).
Encarsia lahorensis is regarded as the most efficient parasitoid of D. citri. Its introduction into various citrus-growing areas of the world has resulted in parasitization levels of up to 70-80%. E. lahorensis has been successfully introduced in Greece, Israel, Italy, Republic of Georgia, Turkey and Uzbekistan (Viggiani and Mazzone, 1978; Pappas and Viggiani, 1979; Argov, 1988, Basova, 1991; Yoldas and Oncuer, 1992). In Florida, USA, E. lahorensis has become well-established in 59 of 67 counties (Sailer et al., 1984). In Alabama, USA, populations of D. citri were drastically reduced one year after the introduction of E. lahorensis, and 3 years after its release, D. citri was no longer a pest in areas where E. lahorensis was present (Hudson and Williams, 1986). Females of E. lahorensis develop as primary endoparasites of D. citri, but the males (which hatch from unfertilized eggs) develop ectoparasitically on female parasite larvae or conspecific pupae within the host; occasionally they may develop on the larvae or pupae of other males, when superparasitism occurs (Viggiani and Mazzone, 1978). Larvae that had almost completed their development and young pupae of both sexes of D. citri appear to be the stages preferred by ovipositing E. lahorensis. E. lahorensis has 4-6 generations per year in southern Italy (Viggianni and Mazzone, 1978), taking 17-25 days to develop from egg to adult.
Impact
Top of pageDiagnosis
Top of pageDetection and Inspection
Top of pageSimilarities to Other Species/Conditions
Top of pagePrevention 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.
IPM ProgrammesControl of D. citri infestations should always be arranged according to the general criteria of integrated control; thus chemical and biological methods should be opportunely balanced to obtain a synergistic effect. Thresholds for the application of an artificial control are generally considered within the European Union as the occurrence of 20-30 whitefly nymphs per leaf on orange and lemon, and of 5-10 whitefly nymphs per leaf on mandarin or mandarin-like citrus species.
Biological Control
In areas where D. citri is a recent introduction, releases of the parasitoid Encarsia lahorensis are often beneficial. Introductions may be achieved using either the 'bouquets' or the 'small plants' methods: the former appears to be more practical for small-scale releases in private orchards, whilst the second is more useful in large-scale releases in large citrus growing areas (see Natural Enemies). Spring and autumn appear to be the best seasons for introducing E. lahorensis.
Chemical Control
Chemical applications usually provide only a temporary suppression of D. citri, which is often followed by resurgence. Thus, chemical control should be considered only for heavy infestations, when it is necessary to quickly reduce the whitefly population before trying to rebuild the balance with the re-introduction of natural enemies. Simple sprayed oils or oil emulsions are generally employed which contain 1% oil in the spray mixture (Priore and Pandolfo, 1972; Barbagallo and Patti, 1978; Ulu, 1987; Uygun et al., 1990). Particular attention should be given to carefully treating the underside of leaves, since the greatest number of nymphs is found there. Trials have been conducted in Israel for the use of the insect growth regulators, buprofezin and pyriproxyfen. The former proved to be more effective on first- and second- instar nymphs, whilst the latter exhibited more ovicidal properties. They were both reported not to adversely affect E. lahorensis (Peleg, 1990).
References
Top of pageAPPPC, 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).
Argov Y, 1988. Biological control of the citrus whitefly, Dialeurodes citri (Ashmead) (Homoptera: Aleyrodidae). Proceedings of the VI International Citrus Congress, Tel Aviv, Israel, 3:1169-1175.
Barbagallo S; Patti I, 1978. Note biologiche ed orientamenti di lotta contro Dialeurodes citri (Ashm.) in Sicilia orientale. Atti Giornate Fitopatologiche, 1:237-244.
Cockerell TDA, 1902. The classification of the Aleyrodidae. Proc. Acad. Nat. Sci. Philad, 54:279-283.
EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization. http://www.eppo.int/DATABASES/pqr/pqr.htm
Nada SMA, 1988. Three species of Aleyrodidae new to Egypt (Aleyrodidae: Homoptera). Bull. Soc. Ent. Egypte, 68:55-59.
Priore R, 1969. Il Dialeurodes citri (Ashmead) (Homoptera: Aleyrodidae) in Campania. Boll. Lab. Ent. Agr. Filippo Silvestri, 27:287-316.
Quaintance AL; Baker AC, 1914. Classification of the Aleyrodidae. Part II. Tech. Ser. Bur. Ent. U.S, 27:95-109.
Rapisarda C, 1990. Gli Aleirodi degli agrumi in Italia. Phytophaga, Palermo, 3(1985-89):173-198.
Distribution References
APPPC, 1987. Insect pests of economic significance affecting major crops of the countries in Asia and the Pacific region. In: Technical Document No. 135, Bangkok, Thailand: Regional Office for Asia and the Pacific region (RAPA).
CABI, Undated. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI
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