Stem borer (Hymenoptera: Cephidae) in Viburnum

Record Details

Record no.:	0604
Feeding guild:	Stem borer
Taxonomy:	Hymenoptera: Cephidae: cf. Janus bimaculatus
Stages observed:	trace, larva
Hosts in Viburnum:	V. lentago (nannyberry)

An affected shoot of the hostplant may die back at the top as a result of the larva tunneling within. The tunneled area fills with frass. The larva possesses a distinctive prong (the "suranal process" in Yuasa (1922)) on the posterior end. I located larvae in 2017 and 2022. I tentatively identify this cephid as Janus bimaculatus based on the host association (see Smith and Solomon (1989)).

Featured Images

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Image #: 604-01 Shoot with necrotic tip, the result of a cephid larva tunneling inside. (Photo date: August 7, 2017)

Image #: 604-02 Necrotic shoot tip. Ruler units are inches.

Image #: 604-03 Affected shoots. (Photo date: August 19, 2017)

Image #: 604-04 Upper portion of stem of affected shoot, densely packed with fine-grained frass produced by larva.

Image #: 604-05 Larva in stem. (Photo date: August 19, 2017)

Image #: 604-07 Larva. Note the prong ("suranal process" in Yuasa (1922)) on the posterior end.

Image #: 604-09 Larva. Note the prong (suranal process) on the posterior end.

Specimen Data for Images

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Coll. 08/07/17, photos same day (01-02); coll. 08/19/17, photos same day (03-09). All specimens above from Iowa, USA.

References

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Smith, D.R. and J.D. Solomon. 1989. A new Janus (Hymenoptera: Cephidae) from Quercus, and key to North American species. Ent. News 100(1):1-5, January & February, 1989.[return to in-text citation]
Yuasa, H. 1922. A classification of the larvae of the Tenthredinoidea. Illinois Biol. Monogr. 7(4):1-172.[return to in-text citation]

Page created: March 10, 2026. Last update: none