Strobilomyia neanthracina (Anthomyiidae)
spiral spruce cone borer
Formerly Hylemya anthracina, and Lasiomma anthracina
||This small black fly (approx. 6 mm long) looks a little
like a housefly. It emerges from the cocoon in spring and searches for the
female cones (megastrobili) on which it lays her eggs.
||The mature maggot is approx. 6 mm long with a pair of distinct
black mouth hooks. Maggot drops to the ground and pupates in the litter in
||Eggs are laid on cone scales in early May or June. Larvae
feed for about one month, consuming seeds and scales around the rachis. From
midsummer onwards, larvae tunnel to the surface of the cone and drop to the
ground where they pupate. A single larva can destroy more than half of the
seeds in one cone.
This species is a major pest of spruce cones.
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