This tool is part of the Citrus Resource

Citrus Pests

 

Seychelles scale

 

Scientific name

 

Icerya seychellarum (Hemiptera: Margarodidae)

Other common names

 

iceplant scale

Similar species

 

Because of the waxy coating, the Seychelles scale may be confused with some species of mealybugs in the family Pseudococcidae.

Distribution

 

United States: not known to occur.

Worldwide: Africa, Australia, Columbia, French Guiana, India, Madagascar, New Zealand, the Pacific Islands, and Southeast Asia.

Native to the Indo-Pacific region.

Diagnostic characteristics

 
Adults
  • Females are covered in white to yellow powdery wax.
  • Body is orange to dark red with areas of bright yellow.
  • Long, fine silky hairs projecting from body.
  • Eyes apparent.
  • Legs and antennae are apparent and black.
  • Double row of rounded plates on either side of an anterior to posterior central ridge occuring on the dorsum.
  • Ovisac present.
  • Mobile.
  • Males are rarely seen when present, but are red-bodied and winged.
Immatures
Eggs

Hosts

 
Citrus hosts
  • All Citrus species and their hybrids.
Non-citrus hosts

Very wide host range. In addition to forest and ornamental species, agricultural crops and weeds are widely used as host plants. A partial list includes:

  • African oil palm, Elaeis guineensis
  • avocado, Persea americana
  • banana, Musa spp.
  • bean, Phaseolus vulgaris
  • carambola, Averrhoa carambola
  • coconut, Cocos nucifera
  • coffee, Coffea spp.
  • Crotalaria spp.
  • fig, Ficus spp.
  • guava, Psidium guajava
  • Hibiscus spp.
  • jackfruit, Artocarpus heterophylla and A. incisa
  • jasmine, Jasminum spp.
  • lettuce, Lactuca sativa
  • loquat, Eriobotrya japonica
  • lychee, Litchi chinensis
  • mango, Mangifera indica
  • morning glory, Convolvulus spp.
  • peach, Prunus spp.
  • pear, Pyrus spp.
  • pepper, Capsicum spp.
  • Plumeria spp.
  • pomegranate, Punica granatum
  • tea, Camellia sinensis
  • strawberry, Fragaria spp.
  • sweet potato, Ipomoea batatas
  • tomato, Solanum lycopersicum
  • trifoliate orange, Poncirus trifoliata

Host damage

 
Fruits
  • Occasionally infested.
  • Honeydew excreted by scales coats the outside of fruit and promotes the growth of sooty mold fungus that inhibits photosynthesis, weakens the plant, and makes fruit unattractive.
Leaves
  • Can be found on stems and near the midribs and on the undersides of older leaves.
  • Can cause yellowing and premature loss.
Stems
  • Primarily infests stems.
Twigs
  • Young shoots can be killed when heavily infested by scales.

Biology

 

Adults can be found on the branches or trunks of trees. Females have both male and female sexual organs (hermaphrodites) and can produce female offspring asexually through parthenogenesis. Eggs 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. Seychelles scales retain their legs, eyes, and antennae for their entire life and remain mobile. Older instars move to the twigs, branches, or the trunk to feed. Males are rare and exist in the species to allow the scale to reproduce sexually producing both females and males. Seychelles scales can have multiple generations per year.

Comments

 

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.

References

 

Butcher, C.F. 1983. Cottony cushion scale, Seychelles scale, and Egyptian fluted scale. Department of Scientific and Industrial Research, Auckland, New Zealand. (http://www.spc.int/pps/PDF%20PALs/PAL%2016%20Scales%201983.pdf).

(CABI) Centre for Agricultural Bioscience International. 2012. Plantwise: pest map for Icerya seychellarum. (http://www.plantwise.org/default.aspxsite=234&page=4393&speciesID=21918&dsID=28434).

Hill, D.S. 2009. Pests of crops in warmer climates and their control. Springer-Verlag, New York.

Authors

 

Weeks, J.A., A.C. Hodges, and N.C. Leppla

 

Citrus Pests
June, 2012
idtools.org