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Species Urophora cardui - Canada Thistle Stem Gall Fly

Fly - Urophora cardui - female Fruit Fly? - Urophora cardui - male Unknown Fly - Urophora cardui  Canada Thistle Stem Gall Fly - Urophora cardui Tephritidae: Urophora cardui - Urophora cardui - male Fruit fly - Urophora cardui - male Urophora cardui? on Cirsium arvense - Urophora cardui Fly - 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