Icerya aegyptiaca (Douglas)
Taxonomic placing: Insecta, Hemimetabola, Hemiptera, Sternorrhyncha, Coccomorpha, Coccoidea, Monophlebidae.
Common name: Breadfruit mealybug, Egyptian mealy bug, Egyptian fluted scale.
Morphology: Body about 3 mm in length, its orange-red color evident through a covering of white wax. The body is surrounded by a fringe of about 20 wax processes, shorter on head and thorax; those on the abdomen cover the ovisac. Legs and antennae black.
Distribution: In most tropical and subtropical regions.
Host plants: About 160 species in about 60 families.
Life history: Icerya aegyptiaca is parthenogenic, and occurs the year round. A generation requires 3-4 months, the pest annually completing two full generations and sometimes a partial third, and its populations peak in late summer. A female lays an average of 70 eggs at 24ºC, twice as much at 27°C. On breadfruit (Artocarpus altilis Fosb.) the crawlers settle along the midribs and larger veins on the underside of leaves and on the fruit. Dispersal is by moving to other leaves or by being wind-borne.
Economic damage: Heavy infestations may kill mature breadfruit trees, but more often the trees are partially defoliated and the crop may be reduced, by 50% or more. In addition, the excreted honeydew is colonized by sootymold that covers the leaves of heavily infested trees and interferes with photosynthesis. The honeydew may be gathered by ants that hamper pest control by its many natural enemies. Other economic plants, such as avocado, banana and citrus, as well as many cultivated ornamentals, can also be attacked. This pest often causes outbreaks in areas with little wind flow, such as the inner areas of bushes. Prolonged dry weather favors its numerical build-up; the size of pest populations may thus vary from year to year.
Management
Cultural control: Removal or low pruning of infested tree parts and destruction of nearby ant nests.
Chemical control: The organophosphate monocrotophos can provide effective control, as may white oils (made from vegetable oil), or soap solutions.
Biological control: The most important enemies of I. aegyptiaca are predatory coccinellids, especially Rodolia cardinalis and Rodolia pumila Weise. Other important enemies include Cryptochetum grandicorne Rondani (Cryptochaetidae) and various parasites of the families Aphelinidae, Eulophidae and Pteromalidae.
References
Azab, A.K., Tawfik, M.F.S. and Ezzat, A.I. 1969. Studies on Icerya aegyptiaca (Douglas) Homoptera: Margarodidae). Bulletin de la Société Entomologique d’Egypte 52: 155-178.
Ragab, M.E. 1995. Adaptation of Rodolia cardinalis (Mulsant) (Col., Coccinellidae) to lcerya aegyptiaca (Douglas) (Homoptera., Margrodidae) as compared with lcerya purchase Mask. Journal of Applied Entomology 119: 621-623.
Uesato, T., Kondo, T., Unruh, C. and Williams, D.J. 2011. Establishment and host records of Icerya aegyptiaca (Douglas) (Hemiptera: Coccoidea: Monophlebidae) in the Sakishima Islands of the Ryukyu Archipelago, Japan, with notes on its worldwide distribution. Entomological Science 14: 49–55.
Waterhouse, D.F. 1993. Biological Control: Pacif’ic Prospects - Supplement 2. AClAR Monograph #20, 138pp.,