Stem borer (Coleoptera: Mordellidae) in Agastache

Record Details

Record no.:	0016
Feeding guild:	Stem borer
Taxonomy:	Coleoptera: Mordellidae: cf. Mordellina pustulata
Stages observed:	trace, larva, adult
Hosts in Agastache:	undetermined A. sp. (giant hyssop)

I found larvae in partially frass-filled hollows in overwintered stems of the host in April (one larva per stem), and an adult emerged in May. The patchy golden mottling on the elytra is consistent with M. pustulata, but this identification has not yet been confirmed.

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long, narrow stretch of hollow stem is packed full of roundish grains of dry frass — Image #: 16-01 Frass in stem.

gray beetle with an arched back and gold spots on the elytra — Image #: 16-02 Adult, lateral.

the beetle's wing covers are partly opened, exposing the wings underneath, and the wing covers are decorated with fine golden hairs arranged in spots — Image #: 16-03 Adult, dorsal.

Page created: October 5, 2025. Last update: none