Schizomyia verbesinae

Distinguished from other Schizomyia species by association with Verbesina host plants; S. verbesinae specifically targets this genus rather than related asteraceous genera such as Solidago or Aster. Gall morphology on Verbesina—often involving stem or leaf axis distortion—differs from the more common leaf-fold or bud galls of congeners. Adult identification requires examination of genitalia and antennal segmentation, best confirmed by specialists.

Adults are small, delicate flies typical of Cecidomyiidae, with long, slender legs, reduced wing venation, and bead-like antennae with circumfilar loops. The larvae are maggot-like, pale, and develop within plant tissue. The galls induced on Verbesina stems or leaves appear as irregular swellings or rosette-like growths.

Found in open, sunny habitats where Verbesina species grow, including prairies, meadows, roadsides, and disturbed areas. Host plants prefer moist to mesic soils, often in floodplains or wetland edges.

Documented in North America, with records from the United States where Verbesina species are native or naturalized. Specific state-level records include areas in the central and eastern United States.

Adult emergence and gall formation occur during the growing season of host plants, primarily late spring through summer. Galls persist on dried plant stems into fall and winter.

Larvae feed on plant tissue within galls, inducing abnormal growth for nutrition and shelter. Adults do not feed; mouthparts are reduced or non-functional.

• Verbesina - gall inducerInduces galls on stems and leaves; specific species of Verbesina not fully documented

Females deposit eggs on Verbesina tissue. Larvae hatch and burrow into plant material, chemically inducing gall formation. Larvae develop through three instars within the gall, then exit to pupate in soil or leaf litter. Adults emerge to mate and oviposit. Likely univoltine or partially bivoltine depending on latitude.

Females exhibit host-specific oviposition behavior, locating Verbesina plants using chemical and visual cues. Larvae remain sedentary within galls, feeding on nutritive tissue they induce. Adults are weak fliers, typically remaining near host plant populations.

Acts as a primary gall inducer, creating habitat for inquilines and parasitoids. Galls may provide shelter for other arthropods. Modest impact on host plant fitness; not considered a significant pest.

No direct economic importance. Occasionally noted by botanists and naturalists as a curiosity. Provides research material for studying plant-insect interactions and gall induction mechanisms.

• Schizomyia racemicolaAlso induces rosette galls on Asteraceae, but targets different host genera (Solidago, Aster) with distinct gall positions and morphology
• Asphondylia speciesOther gall midges on Asteraceae, but Asphondylia typically forms seed or flower galls rather than stem/leaf axis galls

• gall midge
• Cecidomyiidae
• Verbesina
• Asteraceae
• plant gall
• North America

• BugGuide
• iNaturalist taxon