Citrus whitefly

Scientific name

Dialeurodes citri (Hemiptera: Aleyrodidae)

Similar species

cloudy-winged whitefly, Dialeurodes citrifolii

Distribution

United States: Alabama, California, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, Texas, and Virginia.

Worldwide: Argentina, Bermuda, Brazil, Chile, China, Egypt, France, Guatemala, India, Italy, Japan, Macao, Mexico, Pakistan, Peru, Spain, Sri Lanka, Taiwan, Thailand, and Vietnam.

Native to India.

Diagnostic characteristics

Adults

• 1.2 - 1.4 mm (less than 0.1 in.) long.
• Creamy white, coated with white wax.
• Four, white wings on both males and females.
• The life stage immediately before adult is primarily used for identification, but some adult wing patterns can aid determination.

Immatures

• Three nymphal instars followed by a pupal life stage before maturation.
• Up to 1.5 mm (less than 0.1 in.) in length.
• Pale, translucent, and greenish-yellow.
• Flat and oval or elongate-oval, similar to a scale.
• Distinctive "Y" shape on the pseudo-pupa.
• Lack a typical fringe of waxy plates or rods extending outward from the margin of the body present on many other whitefly species.
• Pseudo-pupa is 1.2 - 1.5 mm (less than 0.1 in.) in length; flat, oval and scale-like.

Eggs

• 0.2 - 0.3 mm (less than 0.1 in.).
• Smooth and pale yellow.
• Attached to leaves on a stalk (pedicel).
• Ovoid or pear-shaped.

Hosts

Citrus hosts

• Citrus ponki
• common mandarins (including tangerine), Citrus reticulata
• lemon, Citrus limon
• Mexican (or Key) Lime, Citrus aurantifolia
• sour orange, Citrus aurantium
• sweet orange, Citrus sinensis

Non-citrus hosts

• Allamanda spp.
• ash, Fraxinus excelsior
• boston Ivy, Parthenocissus tricuspidata
• chinaberry, Melia azedarch
• coffee, Coffea arabica
• crepe myrtle, Lagerstroemia indica
• devilwood, Osmanthus americanus
• English ivy, Hedera helix
• Ficus spp.
• Forsythia spp.
• Gardenia spp.
• Hibiscus spp.
• Hercules' club or prickly ash, Zanthoxylum clava-herculis
• Japanese Persimmon, Diospyros kaki
• jasmine, Jasminum officinale
• laurel cherry, Prunus caroliniana
• Ligustrum spp.
• lilac, Syringa vulgaris
• Magnolia figo
• olive, Olea europaea
• Osage orange, Maclura pomifera
• Pittosporum spp.
• plum, Prunus salicina
• pomegranate, Punica granatum
• Smilax spp.
• tree of heaven, Ailanthus altissima
• trumpet vine, Campsis radicans
• water oak, Quercus nigra

Host damage

Fruits

• May retard or delay ripening.
• Honeydew honeydew:
  the sugar-rich waste product excreted by aphids, mealybugs, and scales insects as a result of feeding on the phloem of plants
  excreted by whiteflies coats the outside of fruit and promotes the growth of sooty mold fungus that inhibits photosynthesis, weakens the plant, and makes fruit unattractive.

Leaves

• Damage to leaves removes large quantities of sap which weakens the plant.

Biology

Eggs are deposited on leaves and hatch into mobilemobile:
able to move
first instarinstar:
immature stages (larva or nymph) of insects in between molts
nymphs called crawlers. Crawlers move to the underside of leaves to begin feeding. After the first moltmolt:
process of shedding the external skeleton during periods of growth; occurs between successive instars of a larva or nymph
, the insects lose their legs and are not mobilemobile:
able to move
for the duration of the immature life stages. Citrus whiteflies overwinter as last-instar larvae or pupae. The life cycle takes from 41 - 133 days, and there are often overlapping generations.

Comments

The citrus whitefly was once considered a major pest of citrus, but the introduction of effective parasites and predators have reduced the damage caused by this whitefly.

The citrus whitefly is a suspected vector of Citrus chlorotic dwarf virus because a closely related species, the bayberry whitefly, Parabemisia myricae, is a vector. Further research is required to confirm whether the citrus whitefly is a vector of the virus. Symptoms of the Citrus chlorotic dwarf virus on susceptible citrus hosts were reported as a: "V-shaped notch on one or both sides near the tip of young leaves. In mature leaves, symptoms are crinkling, warping, inverted cupping, and variegation."

All phloem-feeding, honeydew-producing pests have the potential to be tended by ants. The ants feed on the honeydewhoneydew:
the sugar-rich waste product excreted by aphids, mealybugs, and scales insects as a result of feeding on the phloem of plants
excreted by the pest and protect the pest from natural enemies. This protection can disrupt biological control programs.

References

Alford, D. 2007. Pests of fruit crops: A color handbook. Academic Press: Burlington, MA

Byrne, D.N., and T.S. Bellows, Jr. 1991. Whitefly biology. Annu. Rev. Entomol. 36: 431-57

Eberling, W. 1959. Subtropical fruit pests. Univ. Calif., Div. Agric. Sci.: Berkeley, CA.

Fasulo, T.R., and H.V. Weems. 2007. Featured creatures fact sheet: Citrus whitefly, Dialeurodes citri (Ashmead) (Insecta: Hemiptera: Aleyrodidae). Publication EENY-84. University of Florida. (http://entnemdept.ufl.edu/creatures/citrus/citrus_whitefly.htm).

Hodges, G. S., and J. W. Dooley. 2007. A new species of Dialeurodes Cockerell (Hemiptera: Aleyrodidae) on Schefflera Forst and Forst in Florida. Insecta Mundi 0016: 1-5.

Korkmaz, S., A. Cinar, and U. Kersting. 1995. Citrus chlorotic dwarf: A new white-fly transmitted virus-like disease of Citrus in Turkey. Plant Disease 79: 1047. (http://www.apsnet.org/pd/PDFS/1995/PlantDisease79n10_1074.PDF).

Korkmaz, S., U. Kersting, B. Ertugrul, and A. Cinar. 1996. Transmission and epidemiology of citrus chlorotic dwarf (CCD) disease in the Eastern Mediterranean region of Turkey. J. Turkish Phytopathol. 25: 71-76.

Authors

Martin, K.W., J.W. Weeks, A.C. Hodges, and N.C. Leppla