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This tachinid fly is established and
common throughout the North Island and on a number of
offshore islands. Parasitism of brownheaded leafrollers
is very common, including in kiwifruit orchards. This fly
has not been shown to be important in apple orchards,
even though present in the surrounding environment. The
fly normally lays a single egg just behind the head of
the caterpillar (see action picture) so that one
parasitoid is produced from each host. A leafroller
caterpillar parasitised by this fly continues to develop,
usually to the pupal stage before dying. By this stage
the parasite has formed a puparium (inside the leafroller
pupa) from which the adult fly later emerges. There is
circumstantial evidence of leafroller population declines
following the arrival of this parasitoid and the
introduced wasp, Xanthopimpla rhopaloceros. T.
brevifacies has been found to parasitise a number of
other caterpillars from a range of families. |
