Canadian Forest Service Publications

European field collections and Canadian releases of Ceranthia samarensis (Dipt.: Tachinidae), A parasitoid of the Gypsy Moth. 1992. Mills, N.J.; Nealis, V.G. Entomophaga 37(2): 181-191.

Year: 1992

Issued by: Great Lakes Forestry Centre

Catalog ID: 21554

Language: English

Availability: PDF (request by e-mail)

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A programme to collect, import and release into Canada the gypsy moth parasitoid, Ceranthia samarensis (Diptera: Tachinidae) is described. The parasitoid’s potential for biological control in Canada is also discussed. The parasitoid was collected in Europe by exposing experimental gypsy moth larvae in areas where local gypsy moth populations were in low densities. Following field exposure, the host larvae were returned to the laboratory and parasitoids reared from them. This technique has shown that C. samarensis is the predominant parasitoid in these low density gypsy moth populations and that it suffers 7-16% hyperparasitism. From 83-90% of the C. samarensis typically enter diapause as pharate adults within the puparia. Laboratory tests of post-exposure host rearing conditions indicate that constant temperatures disrupt the normal parasitoid diapause and that this effect can not be offset by use of either static long or short photoperiods or natural daylengths. Shipping and cold-storage procedures for puparia are described. Post-storage time to emergence of adult C. samarensis decreased with long cold storage periods and with higher post-storage incubation temperatures. Emergence requires 112 degree-days above a threshold of 8ºC after a period of at least 8 months cold storage. Releases of adult C. samarensis into field cages at four locations in southern Ontario are documented. While dissection of host larvae from the field cages has failed so far to demonstrate evidence of parasitism, we remain hopeful that some establishment of the parasitoid has occurred.