Copidosoma koehleri (Blanchard)
Taxonomic placing: Insecta, Holometabola, Hymenoptera, Chalcidoidea, Encyrtidae.
Distribution: Of South American origin, this species has been mass-reared and released throughout the world.
Hosts: Phthorimaea operculella and a few other related moths.
Morphology: Adult female body shiny black, about 1.6 mm in length. Wings mostly vein-less, leg segments almost black with white patches.
Life history: Copidosoma koehleri is an egg polyembryonic parasitoid. When attacking P. operculella it places many eggs in each host-egg, the offspring often being of the same sex; about 20 male eggs or about 30 female eggs. They develop within the host-egg to their prepupal stage, at which time the host (by now a larva) has become a mummy, from which the adult parasitoids emerge. Mean fertility comes to about 100 eggs/female when feeding on honey and pollen, and it lives for 7-10 days. The development of C. koehleri is fastest at 30ºC, and it requires about 3-4 weeks to complete a generation. The parasitoid is susceptible to low relative humidifies, and is more efficient on leaves with relatively few trichomes.
Economic importance: An important enemy of P. operculella, whose introduction into several countries, such as India and Australia, significantly improved the pest’s control. It is very susceptible to low humidifies that detract from its efficacy, at times requiring augmentation.
References
Gooderham J., Bailey, P.C. E., Gurr, G.M. and Baggen, L. R. 1998. Sub-lethal effects of foliar pubescence on the egg parasitoid Copidosoma koehleri and influence on parasitism of potato moth, Phthorimaea operculella. Entomologia Experimentalis et Applicata 87: 115-118.
Horne, P. A., and Horne, J. A. 1991. The effects of temperature and host density on the development and survival of Copidosoma koehlerii. Entomologia Experimentalis et Applicata 59: 289–292.
Keasar, T. and Steinberg, S. 2008. Evaluation of the parasitoid Copidosoma koehleri for biological control of Phthorimaea operculella in Israeli potato fields. Biocontrol Science and Technology 18 325-336.
Kfir, R. 1981. Fertility of the polyembryonic parasite Copidosoma koehleri, effect of humidities on life length and relative abundance as compared with that of Apanteles subandinus in potato tuber moth. Annals of Applied Biology 99: 225–230.
Pucci, C., Spanedda, A.F. and Minutoli, E. 2003. Field study of parasitism caused by endemic parasitoids and by the exotic parasitoid Copidosoma koehleri on Phthorimaea operculella in Central Italy. Bulletin of Insectology 56: 221-224,
Segoli, M., Bouskila, A., Harari, A. & Keasar, T. 2009. Brood size in a polyembryonic parasitoid wasp is affected by the relatedness among competing larvae. Behavioral Ecology 20 761–767.
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