New Zealand Plant Protection 67 (2014): 325
Mastrus ridens (Horstmann) (Hymenoptera: Ichneumonidae) is a gregarious ectoparasitoid of cocooned larvae of codling moth Cydia pomonella (L.) (Lepidoptera: Tortricidae). This host stage is available for parasitism by M. ridens (which is not known to diapause) throughout winter and early spring. A study was conducted at ambient field temperatures during this period to investigate the minimum temperature required for flight initiation by M. ridens. Ten female and 10 male adults (3-7 days old) from the laboratory were transferred into two containers and placed in an apple orchard for 1 h for temperatures to equilibrate. The container was then opened inside a large net cage, and the numbers of parasitoids that flew into the cage at different temperatures were recorded. The experiment release periods while establishing the parasitoid throughout New Zealand and (2) determine when the females are first active in spring, before the codling moth larvae pupate.
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