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Species Urophora cardui - Canada Thistle Stem Gall Fly

Small fly with striking wings - Urophora cardui canada thistle stem galls  - Urophora cardui Unknown Fly - Urophora cardui - female Unknown Fly - Urophora cardui - female Comparative goldenrod and Canada thistle spherical galls - Urophora cardui Tephritidae, #2, lateral - Urophora cardui Gall on Cirsium, opened - Urophora cardui Urophora cardui? On a thistle species - Urophora cardui
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Diptera (Flies)
No Taxon ("Acalyptratae")
Superfamily Tephritoidea
Family Tephritidae (Fruit Flies)
Subfamily Tephritinae
Tribe Myopitini
Genus Urophora
Species cardui (Canada Thistle Stem Gall Fly)
Explanation of Names
Urophora cardui (Linnaeus 1758)
native to central and southern Europe; introduced to North America for weed control(1)
Canada Thistle (Cirsium arvense)(1)
Life Cycle
One to thirty eggs are laid in stems during plant's growing season. Overwinters in the third instar, mature larva, within a stem gall on Canada thistle. Pupates in early spring.

Release has been approved by the Animal and Plant Health Inspection service (Canada). It is no threat to non target species. Thistle is reduced by as much as 48% and grasses and forbs return to previously infested areas.
Internet References