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common name: cloudywinged whitefly
scientific name: Singhiella (=Dialeurodes) citrifolii (Morgan) (Insecta: Hemiptera: Aleyrodidae: Aleyrodinae)

Introduction - Synonymy - Distribution - Description - Identification - Economic Importance - Hosts - Natural Enemies - Chemical Control - Selected References

Introduction (Back to Top)

Cloudywinged whitefly, Singhiella citrifolii (Morgan), is one of the most common whiteflies associated with citrus in Florida. A native of Asia, it was described by Morgan in 1893 and later by Berger in 1909 from specimens collected in Florida.

Synonymy (Back to Top)

Aleyrodes citrifolii Morgan 1893
Aleyrodes nubifera Berger 1909
Dialeurodes citrifolii (Morgan) (Jensen 2001)

Distribution (Back to Top)

This species occurs in Barbados, Brazil, Bermuda, China, Cuba, Hong Kong, Jamaica, Japan, Malaysia, Puerto Rico, Trinidad, Venezuela, Vietnam, and the United States (Arkansas, Florida, Louisiana, North Carolina, Texas) (Mound and Halsey 1978).

Description (Back to Top)

Adults: The adults are very small, yellowish, with a cloudy spot on the apex of the forewing, and dusted with white powdery wax. When at rest the wings are laid back against the abdomen. Males are smaller than females, with the mean body length 1.28 mm for females and 1.04 mm for males (Quaintance and Baker 1917).

Adult cloudywinged whiteflies, Singhiella citrifolii (Morgan).

Figure 1. Adult cloudywinged whiteflies, Singhiella citrifolii (Morgan). Photograph by R. Nguyen, Division of Plant Industry.

Pupae: Pupae are oval, flattened, membranous, and yellowish-green without an orange spot on the back. The pupal case is opaque after emergence of the adult and the case may collapse and lose its shape. Singhiella citrifolii pupae are readily confused with D. citri, the citrus whitefly, but S. citrifolii is said to be somewhat larger (Hamon 2001).

Nymphs: The immature stages are flat, elliptical in shape and light yellowish in color, and prefer the underside of the leaf. Three larval and one pupal stage occur in the life cycle. The first stage is 0.31 mm long and 0.20 mm wide, second stage 0.58 mm long and 0.38 mm wide, third stage 0.88 mm long and 0.66 mm wide, and pupa (4th stage) 1.44 mm long and 1.09 mm wide (Peracchi 1971).

Immature stages of the cloudywinged whitefly, Singhiella citrifolii (Morgan).

Figure 2. Immature stages of the cloudywinged whitefly, Singhiella citrifolii (Morgan). Photograph by Division of Plant Industry.

Eggs: The eggs are tiny (0.25 mm long), brown, elliptical elongate in shape and most commonly laid on young leaves. The eggs can readily be separated from D. citri because S. citrifolii eggs are dark brown and have a hexagonal pattern on the surface, while D. citri eggs are lighter in color and nearly smooth (Hamon 2001).

Eggs of the cloudywinged whitefly, Singhiella citrifolii (Morgan).

Figure 3. Eggs of the cloudywinged whitefly, Singhiella citrifolii (Morgan). Photograph by R. Nguyen, Division of Plant Industry.

The life cycle from egg to adult ranged from 51 to 334 days with three generations per year in Florida (Morrill and Back 1911).

Identification (Back to Top)

The identification key provided here is designed to identify the four major species of whiteflies that commonly infest citrus in Florida. Another key that covers 16 species of whiteflies that may infest Florida citrus is available on the World Wide Web. This key, developed by the Florida Department of Agriculture and Consumer Services' Division of Plant Industry, uses color photographs of nymphs to assist in identification. It is available at: http://www.freshfromflorida.com/pi/enpp/ento/aleyrodi.html

1a. The whitefly adult is white or white with dark spots on the wings. Nymphs are difficult to see or identify. . . . . 2
1b. The whitefly adult is slate blue in color, eggs are present and laid in spirals. Nymphs are black with prominent spines. . . . . citrus blackfly

2a. The whitefly adult is all white without any dark spots on wings. . . . . citrus whitefly
2b. The whitefly adult is white with a darkened area at the end of each wing. Occasionally a yellow fungus is present. . . . . cloudywinged whitefly
2c. The whitefly female adult is all white and is surrounded by waxy filaments. Eggs are laid in a circle with the female at rest in the center. . . . . wooly whitefly

 

Economic Importance (Back to Top)

The whitefly damages citrus by sucking sap from the leaves. Also, honeydew excreted is a medium for the growth of sooty mold fungi. The sooty mold can cover the fruit and foliage so that it interferes with photosynthesis, and requires that fruit be washed before marketing. In 1977, Encarsia lahorensis became established in Florida, and by 1980 had suppressed the population of D. citri (Nguyen and Sailer 1979, Sailer et al. 1984). Since then, S. citrifolii has gradually replaced D. citri on citrus in central and southern Florida.

Citrus leaves with sooty mold growing on honeydew excreted by the citrus whitefly, Dialeurodes citri (Ashmead).

Figure 4. Citrus leaves with sooty mold growing on honeydew excreted by the citrus whitefly, Dialeurodes citri (Ashmead). Photograph by University of Florida.

Hosts (Back to Top)

Citrus is the most important host of this species. However, it can be found on Ficus nitida (Morrill and Back 1911) and Gardenia sp.

Natural Enemies (Back to Top)

There are several natural enemies of Singhiella citrifolii, including:

Adult coccinellid predator of whitefly nymphs, Delphastus catalinae.

Figure 5. Adult coccinellid predator of whitefly nymphs, Delphastus catalinae. Photograph by Kim Hoelmer, USDA.

Red, Aschersonia aleyrodis, and yellow, A. goldiana, Aschersonia fungi attacking immature whiteflies.

Figure 6. Red, Aschersonia aleyrodis, and yellow, A. goldiana, Aschersonia fungi attacking immature whiteflies. Photograph by University of Florida.

Chemical Control (Back to Top)

Whiteflies also are controlled by sprays applied primarily for control of scale insects. Spraying of commercial citrus exclusively for whitefly control is seldom practiced in Florida. Recommended control measures for commercial or dooryard citrus are significantly different. Please consult the specific management guide for your situation.

Citrus Management Guide for whiteflies in commercial groves
Control of whiteflies on Florida's dooryard citrus trees

It is important to note that spraying with copper for control of harmful fungal diseases will also inhibit growth of "friendly fungi" resulting in an increase in whitefly populations. Also, more than one application of sulfur per year can have an adverse effect on parasites. Spray oil has some insecticidal properties, but is primarily used to remove sooty mold which grows on the fruit and leaves.

Selected References (Back to Top)