Stem miner (Diptera: Agromyzidae) in Eutrochium

Record Details

Record no.:	0230, 0234
Feeding guild:	Stem miner
Taxonomy:	Diptera: Agromyzidae: Ophiomyia sp. (2 spp.?)
Stages observed:	trace, puparium, adult
Hosts in Eutrochium:	E. purpureum (sweet scented joe pye weed); E. maculatum (spotted joe pye weed)

Ophiomyia mines on E. purpureum that I observed tended to spiral around the stem, creating a distinctive pattern. It appeared that frass was typically deposited along the edges of the mine. On E. purpureum, the larva pupates just under the epidermis of the stem at the very base of the plant, with the anterior spiracles projecting through the epidermis. I reared adults in 2022 from overwintered puparia on stems of E. purpureum. I also observed apparent Ophiomyia stem mines on E. maculatum, and a stem mine with a puparium on a cultivated Eutrochium in a garden setting. I do not know whether the mines on E. maculatum, E. purpureum, and the cultivated Eutrochium are all created by the same species.

Featured Images

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Image #: 230-11 Mine of Ophiomyia sp. on stem of Eutrochium purpureum. (Photo date: July 7, 2023)

Image #: 230-14 Stem mine on E. purpureum.

Image #: 230-13 Stem mine on E. purpureum.

Image #: 230-01 Stem mine on E. purpureum. (Photo date: August 22, 2018)

Image #: 230-02 Base of stem, E. purpureum, with puparium (arrow) under epidermis. (Photo date: August 22, 2018)

Image #: 230-03 Anterior spiracles of puparium projecting through stem epidermis.

Image #: 230-04 Stem epidermis peeled back at end of mine, revealing puparium.

Image #: 230-06 Posterior spiracles of puparium.

Image #: 230-20 Stem mine on E. maculatum. (Photo date: August 14, 2022)

Image #: 230-15 Lower stem of a cultivated Eutrochium with Ophiomyia mine. (Photo date: August 25, 2023)

Image #: 230-16 Lower stem of a cultivated Eutrochium with Ophiomyia mine.

Image #: 230-17 Lower stem of a cultivated Eutrochium with Ophiomyia mine, and puparium under the epidermis forming a slight bump (arrow).

Image #: 230-18 Stem of a cultivated Eutrochium from the previous photos (0234-15 through 0234-17), split in half lengthwise at the location of the puparium under the epidermis, revealing the puparium in lateral view, with the rest of the stem beneath it. The tunneling in the stem interior is unrelated to the puparium; it is the work of a mordellid beetle larva.

Image #: 230-19 Puparium in lateral view, just under epidermis of dissected stem.

Image #: 230-07 Base of dead stem, E. purpureum, with overwintering puparium. (Photo date: December 2, 2017)

Image #: 230-08 Puparium overwintering at base of dead stem.

Image #: 230-09 Adult, reared from overwintered puparium on stem of E. purpureum. (Photo date: April 23, 2022)

Specimen Data for Images

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Coll. 08/22/18, photos same day (01-06, on E. purpureum); coll, 09/30/17, photos on 12/02/17 (07-08, on E. purpureum); coll. 04/01/22, adult em. 04/22/22, photos of adult on 04/23/23 (09-10, from E. purpureum); field photos on 07/07/23 (11-14, on E. purpureum); coll. 08/25/23, photos same day (15-19, on a cultivated Eutrochium); field photo on 08/14/22 (20, on E. maculatum).

Page created: November 21, 2023. Last update: February 27, 2026