Species Coccus pseudomagnoliarum (Kuwana, 1914)

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Species Coccus pseudomagnoliarum (Kuwana, 1914)

Citricola Scale, Grey Citrus Scale

Lecanium (Eulecanium) pseudomagnoliarum Kuwana, S.I. 1914. Coccidae of Japan, V. Journal of Entomology and Zoology 6: 1-8 [7].
Coccus citricola Campbell, R.E. 1914. A new coccid infesting citrus trees in California (Hemip.). Entomological News 25: 222-224 [222].
Coccus aegaeus De Lotto, G. 1973. A new soft scale from citrus (Homoptera: Coccoidea: Coccidae). Bollettino del Laboratorio di Entomologia Agraria 'Filippo Silvestri', Portici 30: 291-293 [291].

Taxonomic Decision for Synonymy

Clausen, C.P. 1923. The citricola scale in Japan, and its synonymy. Journal of Economic Entomology 16: 225-226 [225] (Coccus citricola Campbell, 1914)
Tranfaglia, A. 1976. Studi sugli Homoptera Coccoidea. IV. Su alcune Cocciniglie nuove o poco conosciute per l'Italia (Coccidae, Eriococcidae, Pseudococcidae). Bollettino del Laboratorio di Entomologia Agraria 'Filippo Silvestri', Portici 33: 128-143 [129] (Coccus aegaeus De Lotto, 1973)

Ecological Descriptors

Sap-feeder.

ID Keys

(Kosztarab, M., 1996) [337] (female; northeastern North America); (Gill, R.J., 1988) [26] (female; USA, California); (Kawai, S., 1980) [141-142] (female; Japan); (Borchsenius, N.S., 1957) [294] (female; Palaearctic Region).

GENERAL

Good description and illustration of the adult female given by De Lotto, G. 1973. A new soft scale from citrus (Homoptera: Coccoidea: Coccidae). Bollettino del Laboratorio di Entomologia Agraria 'Filippo Silvestri', Portici 30: 291–293 (as C. aegaeus), Tranfaglia, A. 1974. Study on the Homoptera Coccoidea II. Biological note on Asterolecanium arabidis (Signoret) on Hedera helix L. Bollettino del Laboratorio di Entomologia Agraria 'Filippo Silvestri', Portici 31: 54–60 (as C. aegaeus), Gill, R.J., Nakahara, S. & Williams, M.L. 1977. A review of the genus Coccus Linnaeus in America north of Panama (Homoptera: Coccoidea: Coccidae). Occasional Papers in Entomology, State of California, Department of Food and Agriculture 24: 44, Gill, R.J. 1988. The Scale Insects of California: Part 1. The Soft Scales (Homoptera : Coccoidea : Coccidae). Sacramento, California : California Dept of Food & Agriculture 132 pp. and by Kosztarab, M. 1996. Scale insects of Northeastern North America. Identification, biology, and distribution. Martinsburg, Virginia : Virginia Museum of Natural History 650 pp.. Good description of the adult female, first-instar nymph and female second-instar nymph given by Borchsenius, N.S. 1957. Subtribe mealybugs and scales (Coccoidea). Soft scale insects Coccidae. Vol. IX. Fauna SSSR. Zoologicheskii Institut Akademii Nauk SSSR ns 66: 1–493.

BIOLOGY

Develops one annual generation in California (see Quayle, H.J. 1915. The citricola scale. Bulletin University of California Publications, Agricultural Experiment Station, Berkeley 255: 405–421), Israel (see Ben-Dov, Y. 1980. Observations on scale insects (Homoptera: Coccoidea) of the Middle East. Bulletin of Entomological Research 70: 261–271), Greece (see Argyriou, L.C. & Ioanides, A.G. 1975. [Coccus aegaeus (Homoptera, Coccoidea, Coccidae): a new species of soft scale from citrus in Greece.] Coccus aegaeus (Homoptera, Coccoidea, Coccidae) De Lotto: nouvelle espèce de lecanine des Citrus en Grèce. (in French; summary in English). Fruits 30: 161–162, Australia (see Smith, D., Beattie, G.A.C. & Broadley, R.H. 1997. Citrus Pests and their Natural Enemies: Integrated Pest Management in Australia. Brisbane, Australia : State of Queensland, Department of Primary Industries, and Horticultural Research and Development Corp. 263 pp.). Females reproduce parthenogenetically.

STRUCTURE

Adult female elongate oval, slightly convex, up to 7 mm long; dorsum of young female grey with dark brown mottling, while dark grey in older ones. See colour photographs in Kawai, S. 1980. Scale insects of Japan in colors. Tokyo : National Agricultural Education Association 455 pp. [figs. 6.13a, b, c], Gill, R.J. 1988. The Scale Insects of California: Part 1. The Soft Scales (Homoptera : Coccoidea : Coccidae). Sacramento, California : California Dept of Food & Agriculture 132 pp., Tranfaglia, A. & Viggiani, G. 1988. Cocciniglie d'importanza economica in Italia e loro controllo. Portici : Istituto di Entomologia Agraria dell'Universita 30 pp., and Katsoyannos, P. 1996. Integrated insect pest management for citrus in Northern Mediterranean countries. Athens, Greece : Benaki Phytopathologique Institute. 110 pp..

ECONOMIC AND CONTROL

Natural enemies listed by Borchsenius, N.S. 1957. Subtribe mealybugs and scales (Coccoidea). Soft scale insects Coccidae. Vol. IX. Fauna SSSR. Zoologicheskii Institut Akademii Nauk SSSR ns 66: 1–493. This species was a serious pest, in the early 1900's, of citrus in USA, Arizona and California (see Quayle, H.J. 1938. The development of resistance to hydrocyanic acid in certain scale insects. Hilgardia 11: 183–210; Ebeling, W. 1959. Subtropical fruit pests. Los Angeles : Division of Agricultural Sciences, Univ. of Calif. 436 pp.; and Kennett, C.E. 1988. Results of exploration for parasitoids of Citricola Scale, Coccus pseudomagnoliarum (Homoptera, Coccidae), in Japan and their introduction in California. Kontyû 56(2): 455–457). It became less injurious in the 1940's following the application of DDT and other synthetic insecticides. Its economic importance increased during the 1980's – 1990's, because these insecticides lost effectiveness (see Trumble, J.T., Grafton-Cardwell, E.E. & Brewer, M.J. 1995. Spatial dispersion and binomial sequential sampling for citricola scale (Homoptera: Coccidae) on citrus. Journal of Economic Entomology 88: 897–902). Kennett (1988) reported on exploration for parasitoids in Japan. Dreistadt, S.H. 1996. Citricola scale (Homoptera: Coccidae) abundance on Chinese hackberry and scale control with spray oil or acephate trunk implants. Journal of Economic Entomology 89: 481–487 studied the scale during 1991–1994 in USA, California and found that its populations increased in comparison to previous years; the citricola scale was 5–25 times more abundant than Parthenolecanium corni, P. pruinosum and P. cerasorum; three control measures of the citricola scale were evaluated. Trumble et al. (1995) developed in California, USA, a binomial (presence-absence) sampling plan, which was validated for infestations of the citricola scale on orange trees. A minor pest of citrus in Israel (see Ben-Dov, Y. 1980. Observations on scale insects (Homoptera: Coccoidea) of the Middle East. Bulletin of Entomological Research 70: 261–271), Italy (see Longo, S. & Russo, A. 1986. Distribution and density of scale insects (Homoptera, Coccoidea) on citrus-groves in Eastern Sicily and Calabria. Rotterdam : A.A. Balkema) and Australia (see Smith, D., Beattie, G.A.C. & Broadley, R.H. 1997. Citrus Pests and their Natural Enemies: Integrated Pest Management in Australia. Brisbane, Australia : State of Queensland, Department of Primary Industries, and Horticultural Research and Development Corp. 263 pp.).