Depressaria heraclei (formerly
D. pastinacella)
The larva feeds on the flowers and seedheads of hogweed during June
to August and then burrows down into the main stem. It then chews a circular
hole (2-4mm) on the side of the stem before pupating inside the stem. The
adult emerges through the hole in August-September and hibernates as an adult, flying
again in Spring (March-May). Look for the holes in the side of old stems of
hogweed. To confirm the hole was not made by any other insect, split open
the stem and look for the pupal case as shown in photo two, sometimes there can
be more than one pupal case but there is only one exit hole made. (Contributor
K McCabe)
(Awaiting photos)