Scutellista caerulea (Fonscolombe)
(Formerly known as Scutellista cyanea Motschulsky)
Taxonomic position: Insecta, Holometabola, Hymenoptera, Apocryta, Chalcidoidea, Preromalidae.
Geographical distribution: In most warmer regions of the world.
Morphology: The female is shiny-bluish to metallic-black, with a compact body, a strong scutellum and is about 1.5-2.0 mm in length. The legs and antennae are mostly pale brown with dark tips, forewings hyaline except for a strong anterior vein. Male similar but smaller. The larva is whitish-pink, about 3-5 mm long.
Life history: This parasitoid attacks several species of soft scales (Coccidae). Its eggs are placed beneath the the host, in the midst of its eggs, on which the emerging larvae feed. Later they attack the host female, leading to its death. Scutellista caerulea feeds on the honeydew excreted by the coccids, and is not disturbed by ants that are attracted to this nutrient. The rates of oviposition and the sex ratio of S. cyanea are unaffected by high temperature (30°C).
Economic importance: Scutellista caerulea is an important, common biological control agent of Middle Eastern pestiferous Coccidae, like Ceroplastes floridensis, Ceroplastes rusci, Saissetia coffeae and Saissetia oleae. It also attacks Lecanodiaspis africana (Lecanodiaspididae). Rates of parasitism sometimes reach 70%, especially in the autumn. However, at times the occurrence of the parasitoid and suitable host stages may not be synchronized, detracting from the pests’ control.
Although S. caerulea may be quite common, its controlling effect can be offset by the survival of many of the host eggs. After hatching the developing scales may incur some damage.
References
El-Minshawy, A.M., Saad, A. H. and Hammad, S. M. 1978. Efficacy of the natural enemy Scutellista cyanea Motsch. (Hym., Pteromalidae) on Saissetia coffeae Wlk., S. oleae (Bern.) and Ceroplastes floridensis Comst. (Hom., Coccidae). Journal of Applied Entomology 85: 31-37.
Ibrahim, A.G. and Copland, M.J.W. 1987. Effects of temperature on the reproduction of Saissetia coffeae and its parasitoids. International Journal of Tropical Insect Science 8: 351-353.
Morsi, G. A. 2010. Population abundance of the African scale insect, Lecanodiaspis africana Newst. and its parasitoid, Scutellista cyanea Motch. in Upper Egypt. Egyptian Journal of Biological Pest Control 20: 131-134. .
Ragab, M.E. 1995. Efficiency of Scutellista cyanea Motsch. (Hym. Pteromalidae) and Tetrastichus cetoplastae (Gir.) (Hym, Eulophidae) in population suppression of Ceroplastes rusci L. (Hom., Coccidae). Journal of Applied Entomology 119: 627–630.
Rosen D. 1967. On the relationships between ants and parasites of coccids and aphids on citrus. Beitrage zur Entomologie 17:281-286.
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