Icerya purchasi (Hemiptera: Margarodidae)
cottony camellia scale, Pulvinaria floccifera
Icerya genistae
Icerya koebelei
United States: widespread throughout the U.S.
Worldwide: Australia, Fiji, French Polynesia, Guam, Kiribati, Marshall Islands, New Caldonia, New Zealand, Forfolk Island, and Northern Marianas Islands.
Native to Australia.
All Citrus species and their hybrids.
A partial list includes:
Adults can be found on the branches or trunks of trees. Cottony cushion scale females have both male and female sexual organs (hermaphrodites) and can produce female offspring asexually through parthenogenesis. Eggs (600 - 800) are contained within an ovisac attached to the body of the female. Mobile crawlers hatch from the eggs, disperse to a suitable leaf vein, and begin to feed. Cottony cushion scales retain their legs, eyes, and antennae for their entire life and remain mobile. Older instars move to the twigs, branches, or trunk to feed. Males are rare and exist in the species to allow the scale to reproduce sexually producing both females and males. Cottony cushion scales can have 2 - 3 generations per year.
The cottony cushion scale is a serious pest of citrus but is well controlled by the predatory vedalia beetle, Rodolia cardinalis.
All phloem-feeding, honeydew-producing pests have the potential to be tended by ants. The ants feed on the honeydew excreted by the pest and protect the pest from natural enemies. This protection can disrupt biological control programs.
Baker, J.R. 1994. Cottony cushion scale. N.C. State Univ. (http://www.ces.ncsu.edu/depts/ent/notes/Ornamentals_and_Turf/shrubs/note51/note51.html).
Ben-Dov, Y., D.R. Miller, and G.A.P. Gibson. 2009. ScaleNet database, life histories. (http://www.sel.barc.usda.gov/scalenet/lifehist.htm).
Butcher, C.F. 1983. Cottony cushion scale, Seychelles scale, and Egyptian fluted scale. Advisory leaflet 16. South Pacific Commission. (http://www.spc.int/pps/PDF%20PALs/PAL%2016%20Scales%201983.pdf).
Drees, B.M., and J. Jackman. 1999. Field guide to Texas insects. Gulf Publishing Company, Houston, Texas. (http://insects.tamu.edu/fieldguide/bimg116.html).
Ebeling, W. 1959. Subtropical fruit pests. Univ. Calif., Division of Agricultural Sciences.
Essig, E.O. 1938. Injurious and beneficial insects of California. State Commission of Horticulture, California.
Grafton-Cardwell, E.E. 2002. Stages of the cottony cushion scale (Icerya purchasi) and its natural enemy the vedalia beetle (Rodolia cardinalis). Pub. 8051. Univ. Calif., Division of Agriculture and Natural Resources. (http://anrcatalog.ucdavis.edu/IntegratedPestManagement/8051.aspx ).
Grafton-Cardwell, E.E., and M.L. Flint (eds.). 2003. Pest notes: Cottony cushion scale - Integrated Pest Management for Home Gardeners and Landscape Professionals. Pub. 7410. Univ. Calif., Agriculture and Natural Resources. (http://www.ipm.ucdavis.edu/PDF/PESTNOTES/pncottonycushionscale.pdf).
Grafton-Cardwell, E.E. 2008. How to manage pests citrus cottony cushion scale, scientific name: Icerya purchasi. Univ. Calif. IPM Pest Management Guidelines: Citrus, UC ANR Publication 3441(http://www.ipm.ucdavis.edu/PMG/r107301611.html?printpage).
Hamon, A.B. and T.R. Fasulo. 2005. Featured creatures fact sheet: Icerya purchasi Maskell (Insecta: Hemiptera: Margarodidae). EENY-034. University of Florida. (http://entnemdept.ufl.edu/creatures/fruit/cottony_cushion_scale.htm).
Miller, D.R., A. Rung, G.L. Venable, and R.J. Gill. 2007. Scale Insects: Identification tools for species of quarantine significance. CBIT Publishing, Queensland, Australia (http://www.sel.barc.usda.gov/ScaleKeys/ScaleInsectsHome/ScaleInsectsHome.html).
Weeks, J.A., K.W. Martin, A.C. Hodges, and N.C. Leppla