|Crop Knowledge Master|
Toxoptera auranti (Boyer de Fonscolombe)
|Black Citrus Aphid|
Ronald F.L. Mau, Extension Entomologist
Jayma L. Martin Kessing, Educational Specialist
Department of Entomology
This aphid has over 120 hosts that include camellia, cocoa, coffee, Ficus, Hibiscus, Ixora, kamani, lime, macadamia, mango, mock orange, Pittosporum, pomelo and Vanda orchid. Refer to Carver (1978) for an extensive list of host plants in Australia and Leonard & Walker (1971) for California.
The black citrus aphid is found wherever coffee is grown throughout the tropics and subtropics. It is present in South America, Africa, India, eastern Asia and Australia, as well as the Mediterranean region, central America and southern U.S.A. (Carver, 1978). In Hawaii, it is present on all major islands except Lanai.
Aphids feed by sucking sap from their hosts. This often causes the plants to become deformed, the leaves curled and shriveled and, in some cases, galls are formed on the leaves (Metcalf, 1962). In most cases the black citrus aphid is a minor pest of coffee wherever it is found. This pest congregates on the tender young shoots, flower buds and the undersides of young leaves. They are not known to feed on the older and tougher plant tissues (Carver, 1978). On coffee it causes some leaf distortion and malformation of growth of leaves and tips of shoots. It is often more a serious pest in nurseries.
Like other soft bodied insects such as leafhoppers, mealybugs and scales, aphids produce honeydew. This sweet and watery excrement is fed on by bees, wasps, ants and other insects. The honeydew serves as a medium on which a sooty fungus, called sooty mold, grows. Sooty mold blackens the leaf, decreases photosynthesis activity, decreases vigor and causes disfigurement of the host. When the sooty mold occurs on fruit, it often becomes unmarketable or of a lower grade as the fungus is difficult to wash off (Elmer and Brawner, 1975).
Aphids vector many plant diseases which cause substantially greater losses than caused by direct feeding injury. This is often the most damaging feature of an aphid infestation. The black citrus aphid is a vector of virus diseases of Coffea liberica, Coffea arabica var. bullata (blister spot) and Coffea excelsa (ringspot). Fortunately, aphid vectored viruses of coffee have not been reported in Hawaii. On Citrus it is a vector of Citrus tristeza virus, citrus infectious mottling virus and little leaf and lemon-ribbing virus of lemon. Presently, Citrus tritesa virus is the only known citrus virus that occurs in Hawaii.
The development of this aphid is temperature dependent. At 77û F a generation (nymph to adult) may take as little as 6 days. In cooler temperatures (below 59û F), a generation may take as long as 20 days. Higher temperatures also reduce development rate, at 86û F populations of this aphid will sharply decline. Generations are continuous throughout the year in Hawaii.
Eggs are not produced by this species. Females give birth to living young.
There are four nymphal stages of this aphid. The first stage is approximately 1/36 inch in length and the last about 1/17 inch. They are without wings and brownish in color.
Only females are found. They are oval, shiny black, brownish-black or reddish brown in color, either with or without wings, measuring 1/25 to 1/12 inch in body length and having short black-and-white banded antennae. Winged individuals tend to have darker abdomens and be slightly thinner. The incidence of winged individuals is dependent on the population density and leaf age.
Reproduction is partheneogenic or non sexual. Females start reproducing soon after becoming adults. They produce 5 to 7 live young per day, up to a total of about 50 young per female.
Newly born nymphs are found grouped together since mothers do not move about while birthing.
This is the only aphid with an audible stridulation or high piercing sound caused by the aphid rubbing two parts of it body together much like crickets. Large colonies will produce this scrapping sound when they are disturbed.
Several natural enemies of the black citrus aphid keep this pest under control. Sometimes to the extent that insecticides are usually unnecessary. Predators in Hawaii include Allograpta obliqua Say, Chrysopa basalis, Chrysopa microphya McLachlan, Coccinella inaequalis Fabricius, Coelophora inaequalis, Platyomus lividigaster Mulsant and Scymnodes lividgaster. The parasites in Hawaii include Aphelinus semiflavus Howard and Lysiphlebus testaceipes (Cresson). There are many other predators and parasites to this pest throughout the world. This pest is also controlled by the entomogenous fungus Acrostalagmus albus.
If chemical control becomes necessary either insecticidal oil, or a synthetic aphidicide(insecticide) may be used. Chemical control should only be applied at the first signs of damage during periods of flush growth. Flush growth (young red leaves) on coffee should be completely moistened after application of chemicals.
Blackman, R.L. and V.F. Eastop. 1984. Toxoptera aurantii (Boyer de Fonscolombe) Black Citrus Aphid. pp. 364-365. Aphids on the World's Crops: An Identification and Information Guide. John Wiley & Sons, Chichester, New York, Brisbane, Toronto, Singapore, 466 pages.
Carver, M. 1978. The Black Citrus Aphids, Toxoptera citricidus (Kirkaldy) and T. auranti (Boyer de Fonscolombe) (Homptera: Aphidiae). J. Aust. Entomol. Soc. 17: 263-270.
Elmer, H.S. and O.L. Brawner. 1975. Control of Brown Soft Scale in Central Valley. Citrograph. 60(11): 402-403.
Firempong, S. 1977. Biology of Toxoptera aurantii (Homoptera: Aphididae) on cocoa in Ghana. J. Nat. Hist. 11: 409-416.
Harris, K.M. 1970. Black Citrus Aphid (Toxoptera auranti (Boy.) on Camellias. Plant Pathology. 19:48.
Hill, D.S. 1983. Toxoptera aurantii (B. de F.). pp. 205-206. In Agricultural Insect Pests of the Tropics and Their Control, 2nd Edition. Cambridge University Press. 746 pages.
Leonard, M.D. and H.G. Walker. 1971. Host Plants of Toxoptera aurantii at the Los Angeles State and County Arboretum, Arcadia, California. Proc. Entomol. Soc. Washington. 73: 324-326.
LePelley, R.H. 1968. Toxoptera aurantii Boyer de Fonscolombe 1841. pp. 311-312. In Pests of Coffee. Longmans, Green & Co., Ltd., London and Harlow. 590 pages.
Metcalf, R.L. 1962. Destructive and Useful Insects Their Habits and Control. McGraw-Hill Book Company; New York, San Francisco, Toronto, London. 1087 pages.
Toba, H.H. 1962. Studies on the Host Range of Watermelon Mosaic Virus in Hawaii. Plant Dis. 46: 409-410.
Rivnay, E. 1938. Factors Affecting the Fluctuations in the Population of Toxoptera aurantii Boy. in Palestine. Annals of Applied Biology. 25: 143-154.
Zimmerman, E.C. 1948. Toxoptera aurantii (Boyer de Fonscolombe). pp. 100. In Insects of Hawaii. A Manual of the Insects of the Hawaiian Islands, including Enumeration of the Species and Notes on Their Origin, Distribution, Hosts, Parasites, etc. Volume 5. Homoptera: Sternorhyncha. 464 pages.