Toxoptera aurantii (Boyer de Fonscolombe)
Taxonomic placing: Insecta, Hemimetabola, Hemiptera, Sternorrhyncha, Aphidoidea, Aphididae.
Common name: Black citrus aphid.
Geographical distribution: This pest occurs throughout the tropical and subtropical parts of the world and has invaded glasshouses in cooler regions. Commonwealth Institute of Entomology Map #131, 1961.
Host plants: Polyphagous.
Economic importance: The black citrus aphid is a pest of citrus, especially of the young growth. Feeding causes leaf curling and twisting, albeit not to the same extent as the attacks of Aphis spiraecola. Infested buds and flowers may drop. Abroad T. aurantii transmits the citrus tristeza virus, but this has not been confirmed in the Middle East.
Morphology: The body of apterous and alate females, including the siphunculi and cauda, is dark-brown to black. The body of the apterae is 1.4-2.1 mm long, that of the alatae is 1.5 -1.7 mm long.
Life cycle: Apterous females complete a generation in about one week at 25ºC, in less than three weeks at 15ºC, and development ceases above 32ºC. The pest is very susceptible to khamsin events, which along with the maturing of citrus leaves, greatly reduce its populations. A second, autumnal outbreak often takes place. The calculated threshold of development was 3.8ºC and each female produced about 60 progeny at 20ºC. In the Middle East the aphid reproduces by viviparous parthenogenesis throughout the year, completing about 30 annual generations.
Management
Chemical control: This aphid is a minor pest, whose autumnal outbreaks may be controlled with organophosphates.
Biological control: The black citrus aphid is attacked by several endoparasitoids of the families aphidiids (like Lysiphlebus fabarum) and aphelinids, especially during autumn. The populations of the pest also suffer from infections of entomopathogenic fungi.
References
Mescheloff, E. and Rosen, D. 1990. Biosystematic studies on the Aphidiidae of Israel (Hymenoptera: Ichneumonoidae). 3. The genera Adialytus and Lysiphlebus. Israel Journal of Entomology 24: 35-50.
Swirski, E. and Amitai, S. 1999. Annotated list of aphids (Aphidoidea) in Israel. Israel Journal of Entomology 33: 1-120.
Swirski, E., Wysoki, M and Izhar, Y. 2002. Subtropical Fruits Pests in Israel. Fruit Board of Israel (in Hebrew with an English Preface).
Wang, J.J. and Tsai, J.H. 2001. Development, survival and reproduction of black citrus aphid, Toxoptera aurantii (Hemiptera : Aphididae), as a function of temperature. Bulletin of Entomological Research 91: 477-487.