"The characteristic color of the galls is only in the epidermis, which is 1 cell layer thick. When the epidermis is peeled away, a mat of white fungal tissue can be seen below...hard, black carbonaceous material...encases the larva or larvae."

[He lists the following host records for this species, verified by both host and insect identification: Aster choralis [probably a Symphyotrichum cordifolium complex member], Aster ciliolatus [S. ciliolatus], A. coerulescens [probably a S. lanceolatum complex member], A. cordifolius [S. cordifolium], A. divaricatus [Eurybia divaricata], A. dumosus [S. dumosum], A. ericoides [S. ericoides], A. falcatus [S. falcatum], A. laevis [S. laeve], A. lateriflorus [S. lateriflorum], A. novae-angliae [S. novae-angliae], A. oblongifolus [S. oblongifolium], A. ontarionis [S. ontarionis], A. paternus [Sericocarpus asteroides], A. pilosus [Symphyotrichum pilosum], A. puniceus [Symphyotrichum puniceum], A. sagittifolius Wedemeyer [S. cordifolium], A. schreberi [E. schreberi], A. simplex [probably a S. lanceolatum complex member], A. undulatus [S. undulatum]]

[He also lists the following additional Symphyotrichum species as possible Asteromyia hosts based on observations of galls only (no insect material available). These gall records are included on this page because this midge species seems to specialize on this host genus, but see the "gallformers notes" for possible exceptions to this trend:
Aster anomalus [Symphyotrichum anomalum], A. azureus [S. oolentangiense], A. elliottii [S. elliottii], A. lowrieanus [S. lowrieanum], A. lucidulus [S. firmum], A. novibelgii [S. novi-belgii], A. occidentalis [S. spathulatum], A. praealtus [S. praealtum], A. sericeus [S. sericeum], A. shortii [S. shortii]]

[as Choristoneura laeviana]: "bred September 1, 1906, from a whitish blister gall on Aster laevis [Symphyotrichum laeve]…"

[as Choristoneura paniculata]: "bred August 10, 1906, from a yellowish or brownish oval blister gall on Aster paniculata [S. lanceolatum]..."

[as Choristoneura helena]: "bred July 1907 from round blister galls on Aster lateriflorus [Symphyotrichum lateriflorum] taken at Highland, NY…"

[as Baldratia paniculata]: "blister galls [on] [Aster] paniculata [Symphyotrichum lanceolatum] [that are] oval, yellowish, or brownish"

[as Baldratia laeviana]: "blister galls [on] [Aster] laevis [S. laeve] [that are] oval, whitish"

[as Baldratia flavomaculata]: "blister galls [on] [Aster] laevis [S. laeve] [that are] small, yellowish"

[as Baldratia fuscoanulata]: "blister galls [on] [Aster] laevis [S. laeve] [that are] yellowish white, dark margined"

[as Baldratia asterifoliae]: "blister galls [on] [Aster] laevis [S. laeve] [that are] purplish white"

[as Baldratia pustulata]: "pustulate gall on stem"

Asteromyia species were identified using characters of mature larval and pupa (particularly the shape of the sternal spatula) using Gagné (1968) and with reference to gall morphology and host-plant affiliation (Gagné, 1968, 1994). All galls were categorized as to whether a thick mat of fungal hyphae or hyphal stroma was present or absent.
...
[from Appendix A – "Samples used mtDNA analyses with host-plants, collection site, and Genbank accession number", hosts sampled included: Eurybia radula, Symphyotrichum puniceum, S. cordifolium, S. laeve, S. lanceolatum, S. lateriflorum, S. pilosum, S. prenanthoides, S. urophyllum]
...
GF note: The record from Eurybia radula is from Greene Co., OH, which is not near the native range for this host plant. Because this plant is relatively rare, and not frequently cultivated, I suspect that this may be a misidentification.

"gall greenish yellow or papery white, diameter 1.75 cm.; on Aster laevis [Symphyotrichum laeve]]…."

[as Asteromyia pustulata, on "aster"]: "gall a small, pustulate swelling on aster stems, diameter 3mm…"

[as Asteromyia dumosae, on "aster"]: "gall yellowish brown, narrowly oval, length 4 mm., diameter 2 mm…."

[as A. waldorfi, on "aster"]: "gall yellowish, shining, oval, diameter 6 to 7 mm…"
"

[as A. nitida, on "aster"]: "gall yellowish, shining, oval, diameter 6 to 7 mm…"

[as A. divaricata on Aster divaricatus [Eurybia divaricata]]: "gall pinkish, large, oval blotches on Aster divaricata, diameter 10 to 12 mm…" [Gagné (1968) assigned this to Asteromyia laeviana, not A. clarkei, presumably based on adult insect morphology, but is the host correctly identified?]

[as A. marginata, on "aster"]: "gall yellowish or brownish, irregularly oval, diameter 3 mm…." [Gagné (1968) noted that the host in the type material is "probably A. simplex [S. lanceolatum]]

[as A. flavomaculata, on "aster"]: "gall sooty yellow beneath, dirty white above, length 2 cm., diameter 1.2 cm…"

[as A. asterifolia, on "aster"]: "gall yellowish white, dark margined, diameter 3 mm…."

Lasioptera asterifoliae sp. nov.

Gall.--Circular, flattened, eye-like blotches on the leaf of a species of aster, measuring about 5 mm in diameter. Purplish with a sordid whitish centre and margin. Underside dull whitish. Found singly or in numbers, all depending upon the size of the leaf.

Habitat: NC

The larva pupates within the gall and the fly emerges during the same year in August and early in September.

This gall midge is responsible for a leaf blister gall on Symphyotrichum laeve. The galls are light yellow to gray in color.