Black citrus aphid

Scientific name

Toxoptera aurantii (Hemiptera: Aphididae)

Other common names

black orange aphid

Similar species

brown citrus aphid, Toxoptera citricida

• 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. 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>
  can also distinguish the brown citrus aphid from the black citrus aphid. Both winged and wingless forms of the brown citrus aphid have more than 30 setae. The winged form of the black citrus aphid has 8 - 19 setae while the wingless form has 9 - 19 setae.
• Black 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: Alabama, Arizona, California, District of Columbia, Florida, Georgia, Hawaii, Louisiana, Maryland, New York, North Carolina, Oregon, Texas, and Washington.

Worldwide: Cosmopolitan; everywhere host plants are grown in the tropics and subtropics, including Africa, Australia, eastern Asia, India, Central and South America, the Mediterranean region, and the Pacific Islands.

Diagnostic characteristics

Adults

• Females are 1.1 - 2.0 mm (less than 0.1 in.) in length for both winged and wingless forms. Females are used for diagnostic purposes.
• Wingless forms (apterous) range from shiny, reddish-brown, brownish-black, to black in color. Top of abdomenabdomen:
  one of the three body segments in insects; the most posterior segment containing the heart, reproductive organs, and digestive organs
  (dorsum) is not shiny.
• Winged forms (alates) have a dark brown to black abdomenabdomen:
  one of the three body segments in insects; the most posterior segment containing the heart, reproductive organs, and digestive organs
  . The top of the abdomenabdomen:
  one of the three body segments in insects; the most posterior segment containing the heart, reproductive organs, and digestive organs
  (dorsum) is not shiny.
• Cauda cauda:
  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>
  (a triangular protrusion on 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
  ) is dark in color. In the wingless form (aptera), 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 9 - 19 setae. In the winged form, 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 8 - 19 setae.
• A pair of black 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>
  are almost twice as long as 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>
  .
• Pear-shaped.
• No markings on the wings, but the front edge of the forewings (pterostigma) between the mid-point and the wing tip is black.
• The media vein of the wing (originating to the left of the pterostigmapterostigma:
  a thickened cell on the outer margin of the wing in some insects
  ) is distinctive since it has only one branch.
• Six-segmented antennae with black and white bands.
• Tubercles (head area between antennae) are not prominent, relatively flat instead of having a notched appearance.

Immatures

• Four nymphal instars.
• Approximately 0.028 - 0.059 mm (less than 0.1 in.) in length.
• Brownish in color.

Eggs

• Females produce live offspring.

Hosts

Citrus hosts

All Citrus species and their hybrids.

Non-citrus hosts

Broad host rangehost range:
the range of species that a particular organism can feed on to achieve successful growth and reproduction
, including weeds as well as vegetable, field, and flower crops. Black citrus aphids feed on 190 genera of plants from 80 different families including:

• Annona spp.
• avocado, Persea americana
• black pepper, Piper nigra
• Camellia spp.
• Cinchona spp.
• coffee, Coffea arabica
• fig, Ficus carica
• jackfruit, Artocarpus heterophylla and A. incisa
• lychee, Litchi chinensis
• loquat, Eriobotrya japonica
• Macadamia integrifolia and M. tetraphylla
• mango, Mangifera indica
• tea, Camellia sinensis
• Theobroma bicolor

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

• Infests and can cause deformation of new growth.
• Black citrus aphids are capable of transmitting Citrus tristeza virus (CTV) (see Comments section).

Twigs

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

Biology

The black citrus aphid reproduces asexually (parthenogenesis), allowing rapid population growth. The aphid's life cycle is temperature-dependent, and individuals can mature in as little as six days at 25 °C (77 °F) and approximately 20 days at temperatures lower than 15 °C (59 °F). They are usually tended by ants that offer them protection from natural enemies. The aphid is somewhat unusual since it can produce an audible noise when it moves small spines on its legs (tibiae) along the serrated cuticle on the each side of its abdomenabdomen:
one of the three body segments in insects; the most posterior segment containing the heart, reproductive organs, and digestive organs
. Large colonies can be heard when they are disturbed.

Comments

Black citrus aphids are capable of transmitting Citrus tristeza virus (CTV). Citrus propagated on sour orange rootstock are particularly susceptible to the virus. The melon or cotton aphid, Aphis gossypii, and the brown citrus aphid, Toxoptera citricida, are more effective vectors of CTV. Current isolates of CTV only affect trees on susceptible root stocks such as sour orange; no resistant root stock is known for CTV. However, there are tolerant resistant rootstocks that include Troyer, Trifoliate, and c22. Overall, 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 black citrus aphid include Aphis aunantii.

References

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

Carver, M. 1978. The black citrus aphids, Toxoptera citricidus (Kirkaldy) and T. aurantii (Boyer de Fonscolombe) (Homoptera: Aphididae). J. Aust. Entomol. Soc. 17: 263-270.

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).

Fasulo, T.R., and S.E. Halbert. Aphid pests of Florida citrus. (http://edis.ifas.ufl.edu/pdffiles/CH/CH05500.pdf).

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.: Div. Plant Industry. (www.doacs.state.fl.us/pi/enpp/ento/entcirc/ent374.pdf).

Joshi, S., and J. Poorani. 2007. Aphids of Karnataka: Toxoptera aurantii (Boyer de Fonscolombe) fact sheet. (http://www.aphidweb.com/Aphids%20of%20Karnataka/Toxopteraaurantii.htm).

(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.

Szentkirályi, F. 2001. Lacewings in fruit and nut crops, pp. 172-238. In P.K. McEwen, T.R. New, and A.E. Whittington (eds.). Lacewings in the crop environment. Cambridge University Press, Cambridge, U.K.

Authors

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