Brown citrus aphid

Scientific name

Toxoptera citricida (Hemiptera: Aphididae)

Other common names

oriental citrus aphid, tropical citrus aphid

Similar species

black citrus aphid, Toxoptera aurantii

• Adult aphids should be used for identification.
• The black citrus aphid is somewhat smaller than the brown citrus aphid it resembles.
• When the brown citrus aphid is squashed on a white surface it produces a red color while other aphids in the genus Toxoptera, like the black citrus aphid, do not produce the same color.
• The number of hairs (setae) on the caudacauda:
  a v-shaped structure extending from the rear of the aphid abdomen <a href="http://idtools.org/id/citrus/pests/morphology.php?state[]=abdomen#abdomen"></a>
  also differs between the black citrus aphid and brown citrus aphid. Both winged and wingless forms of the brown citrus aphid have 30 setae. The winged form of the black citrus aphid has 8 - 19 setae while the wingless form has 9 - 19 setae.
• Brown citrus aphids can occur in mixed groups with other aphid species.

cotton aphid, Aphis gossypii

cowpea aphid, Aphis craccivora

mango aphid, Toxoptera odinae

oleander aphid, Aphis neri

spirea aphid, Aphis spiraecola

Distribution

United States: Florida.

Worldwide: Africa, Asia, Australia, New Zealand, the Caribbean, and South America.

Diagnostic characteristics

Adults

• 1.5 - 2.8 mm (less than 0.1 - 0.11 in.) in length.
• Winged adults are shiny, dark-brown to black; wingless adults are shiny black.
• A darker band occurs where the two longest leg segments (femur and tibiatibia:
  from the base of the insect body, the tibia is the fourth segment of the insect leg, situated between the femur and the tarsus
  ) meet.
• Pear-shaped with two corniclescornicles:
  paired, triangular-shaped tubes projecting from the rear of an aphid abdomen; also referred to as siphunculi <a href="http://idtools.org/id/citrus/pests/morphology.php?state[]=abdomen"></a>
  positioned at the rear of the abdomenabdomen:
  one of the three body segments in insects; the most posterior segment containing the heart, reproductive organs, and digestive organs
  .
• Six segmented antennae.
• In wingless aphids, the antennae do not appear to be striped. The dark portion of antennae is about ½ its length.
• In winged aphids, there are three black antennal segments closest to the headhead:
  one of the three main body segments in insects; the anterior-most segment containing the many sensory structures including the eyes, antennae, and mouthparts
  .
• The rear of the abdomenabdomen:
  one of the three body segments in insects; the most posterior segment containing the heart, reproductive organs, and digestive organs
  has a small, short, dark, tail-like structure (cauda) that is slightly shorter than the tube-like corniclescornicles:
  paired, triangular-shaped tubes projecting from the rear of an aphid abdomen; also referred to as siphunculi <a href="http://idtools.org/id/citrus/pests/morphology.php?state[]=abdomen"></a>
  and is either tongue- or triangle-shaped.
• The caudacauda:
  a v-shaped structure extending from the rear of the aphid abdomen <a href="http://idtools.org/id/citrus/pests/morphology.php?state[]=abdomen#abdomen"></a>
  has about 30 hairs (setae).

Immatures

• Reddish-brown color.
• Smaller, but closely resembles the adults.

Eggs

• Reproduces asexually in most of the world but is reported to reproduce sexually in Japan.

Hosts

Citrus hosts

All Citrus species and their hybrids.

Non-citrus hosts

No confirmed alternate hosts.

Host damage

Flowers

• Infests and damages buds and flowers.
• Infestation can stop bud growth and cause buds to drop.

Fruits

• Not reported to damage citrus fruit but can damage fruit ofAnnona spp.
• 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 aphids coats the outside of fruits and leaves and promotes the growth of sooty mold fungus that inhibits photosynthesis, weakens the plant, and makes fruit unattractive.

Leaves

• Curled and distorted leaves, stunted plant growth.
• Infests and can cause deformation of new growth.
• Brown citrus aphids are effective vectors of Citrus tristeza virus (CTV)(see Comments section).

Twigs

• Infests new soft twigs, weakening trees and stunting growth.

Biology

Brown citrus aphids are considered one of the most serious pests of citrus. They reproduce both sexually and asexually (parthenogenesis) to produce live young. They are typically found in large numbers covering stems, leaf veins, and the underside of leaves. They prefer new growth. They are reported to feed exclusively on species of Citrus or other plants in the family Rutaceae. Winged forms of the brown citrus aphid typically develop when new growth is no longer available on the tree so they can disperse. Aphids are capable of wide dispersal and can travel up to 30 kilometers.

Comments

Brown citrus aphids are known to efficiently transmit Citrus tristeza virus (CTV). Citrus propagated on sour orange rootstock are particularly susceptible to the virus. The melon or cotton aphid, Aphis gossypii, and several other species can also transmit CTV. Current isolates of CTV only affect trees on susceptible root stocks such as sour orange; no resistant root stock is known for CTV. CTV can cause major economic losses. A tree infected with CTV typically dies within 1-5 years.

All phloem-feeding, honeydew-producing insect 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.

Synonyms of the brown citrus aphid include Aphis citricidus.

References

Blackman, R.L., and V.F. Eastop. 2000. Aphids on the world's crops: an identification and information guide, 2nd ed. Wiley publishing, Chichester, Great Britain.

Chung, K.R., and R.H. Brlansky. 2008. Citrus diseases exotic to Florida: Citrus tristeza virus-stem pitting (CTV-SP), Pub. PP-227. Plant Pathology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. (http://edis.ifas.ufl.edu/pp149).

Grafton-Cardwell, E. 2008. U.C., IPM pest management guidelines: citrus, Pub. 3441. University of California, Agriculture and Natural Resources. (http://www.ipm.ucdavis.edu/PMG/r107305011.html).

Halbert S.E., and L. Brown. 2001. Featured creatures fact sheet: Brown citrus aphid, Toxoptera citricida (Kirkaldy) (Insecta: Hemiptera: Aphididae). Publication EENY-7. University of Florida. (http://www.entnemdept.ufl.edu/creatures/CITRUS/BC_Aphid.htm).

Halbert, S.E., and L.G. Brown. 1998. Toxoptera citricida (Kirkaldy), Brown citrus aphid-identification, biology, and management strategies. Entomol. Circ. 374, Flor. Depart. Agric. and Consumer Serv.: Division of Plant Industry (http://www.doacs.state.fl.us/pi/enpp/ento/entcirc/ent374.pdf).

Komazaki, S. 1987. Growth and reproduction in the first two summer generations of two citrus aphids, Aphis citricola van der Goot and Toxoptera citricidus (Kirkaldy) (Homoptera: Aphididae), under different thermal conditions. Appl. Entomol. Zool. 23: 220-227.

Michaud, J.P. 1998. A review of the literature on Toxoptera citricida (Kirkaldy) (Homoptera: Aphididae). Flor. Entomol. 81: 37-61.

(NAPIS) National Agricultural Pest Information System. Purdue University. 2012. Survey Status of Brown Citrus Aphid - Toxoptera citricidus (2008 to present). (http://pest.ceris.purdue.edu/pest.php?code=IRACDWA).

(OEPP/EPPO) European and Mediterranean Plant Protection Organization. 1980. EPPO/OEPP data sheet on quarantine organisms, no. 45: Toxoptera citricidus. (http://www.eppo.org/QUARANTINE/insects/Toxoptera_citricida/TOXOCI_ds.pdf).

(OEPP/EPPO) European and Mediterranean Plant Protection Organization. 2006. Diagnostic protocol - Toxoptera citricidus. OEPP/EPPO Bulletin 36: 451-456. (http://www.furs.si/law/EPPO/zvr/ENG/EPPO2004/diag_protokoli_PM7/pm7-75.pdf).

Stoetzel, M.B. 1990. Some aphids of importance to the Southeastern United States (Homoptera: Aphididae). Flor. Entomol.73: 580-586.

Stoetzel, M.B. 1994. Aphids (Homoptera: Aphididae) of potential importance on Citrus in the United States with illustrated keys to species. Proc. Entomol. Soc. Wash. 96: 74-90.

Tsai, J.H., R.F. Lee, Y.H. Liu, and C.L. Niblett. 2009. Biology and Control of Brown Citrus Aphid (Toxoptera citricida Kirkaldy) and Citrus Tristeza. In Radcliffe's IPM World Textbook. (http://ipmworld.umn.edu/chapters/tsaietal.htm).

Authors

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