Icerya seychellarum (Westwood)
Common name: Seychelles scale.
Taxonomic placing: Insecta, Hemimetabola, Hemiptera, Sternorrhyncha, Coccomorpha, Coccoidea, Monophlebidae.
Distribution: South-East Asia, Africa, Southern Europe, Australia and South America. CABI/Eppo, 2008. Distribution Maps of Plant Pests, No. 52.
Morphology: The body of adult females is about 7-10 mm in length, initially yellow, later becoming orange to red, and is partially obscured by yellow-white wax. Mature scales have a fringe of slender glassy filaments and a lobed margin around their bodies; they also bear hair-like setae on all body segments. Legs and antennae black.
Life history: Icerya seychellarum is hermaphroditic, males being very rare. It is dispersed by its wind-blown crawlers.
Host plants: Polyphagous.
Economic importance: The damage caused by this pest is due to its sucking the host’s sap and to the excretion of much honeydew that is colonized by sootymold. Together they reduce photosynthesis, lead to leaf drop and to stunted growth. This scale is a pest of many commercial crops, such as avocado, guava and citrus, and is of importance on grapevines and mango in Egypt.
Management
Chemical control: A pyrethroid, an insect growth regulator and entomopathogenic fungi provided satisfactory control of the pest on mango in Egypt.
Biological control: Several Coccinellidae, like Rodolia cardinalis prey on the pest and control it, provided their effect is not curtailed by ants. Effective control has been achieved in Mauritius by introducing the parasitic fly Chryptochetum monophlebi (Skuse) (Cryptochaetidae).
References
Bakry, M.M.S, Fouad, M.S., Moussa, S.F.M. and Ahmed, F.F. 2015. Field evaluation of some insecticides against Insulaspis pallidula and Icerya seychellarum on mango trees at Qena Governorate, Egypt. AshEse Journal of Agricultural Science 1: 28-32.
Bedford, E. C. G. 1965. An attempt to control the Seychelles scale, Icerya seychellarum (Westwood) (Homoptera: Coccidae) in South Africa by introducing Cryptochaetum monophlebi Skuse (Diptera: Cryptochaetidae). Journal of the Entomological Society of Southern Africa 28: 155-65.
Hill, M.G. 1980.Wind Dispersal of the coccid Icerya seychellarum (Margarodidae: Homoptera) on Aldabra Atoll. Journal of Animal Ecology 49: 939-957.
Hill, M.G. and Blackmore P.J.M. 1980. Interactions between ants and the coccid Icerva seychellarum on Aldabra Atoll. Oecologia 45: 360-365.
Mangoud, A.A.H. 2010. The efficiency of the vedalia beetle, Rodolia cardinalis (Mulsant) (Coleoptera: Coccinellidae) in suppressing populations of Icerya seychellarum (Westwood) (Homoptera: Monophlebidae) on grape vines in Egypt. Proceedings of the XII Interanational Symposium on Scale Insect Studies, Chania, P. 63.
Mesbah, H.A. (and 6 co-authors) 2009. Efficacy of five volatile oils and their mixtures against the mealybug, Icerya seychellarum (Westw.) infesting Sago palm, Cycas revolute in Alexandria, Egypt. Communications in Agriculture and Applied Biological Science 74: 445-55.