Upper Midwest Stem Insect Survey

Stem borer (Coleoptera: Curculionoidea) in Chenopodium

Record Details

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Record no.:0145
Feeding guild:Stem borer
Taxonomy:Coleoptera: Curculionoidea: cf. Curculionidae: Cosmobaris sp.
Stages observed:trace, larva, adult
Distribution observed:IA, MN
Hosts in Chenopodium:undetermined C. sp. (lamb's-quarters)

I reared adults from overwintered dead stems in spring 2017, and photographed larvae in stem pith of dead stems in winter 2025-2026 and living stems in late August 2022. Larvae were pale yellowish grubs with a well-defined, darker head capsule, and are only tentatively placed here with the reared adults from 2017. The adults appeared similar to weevils reared by M. Palmer and identified as Cosmobaris sp. on BugGuide.net (Palmer 2018).

References

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Page created: March 22, 2026. Last update: March 22, 2026