ID of larva is tentative, based on larva's appearance coupled with this rearing from the same county, same microhabitat


Posting in order to share what this insect's sign looks like on one of its hosts in this area.

This series shows a section of figwort (Scrophularia sp.) stem with an E. hebesana larva overwintering inside. The larva has made a hole in the stem, shown in the first photo. In my experience a hole like this, round(ish) with that distinctive, light-colored "sanded area" around it, is a telltale sign of the presence of E. hebesana in the stem. The second photo shows the same hole and the section of stem adjacent to it, after I split the stem in half along its length. As you can see, the pith has been tunneled, and the tunnel leads from the hole to the overwintering larva.

Based on the prevalence of this sign and the corresponding larvae, figwort is a significant host for E. hebesana in my area. I would say that well over half of the figwort stems I've inspected during winter in Winneshiek County host overwintering larvae.