Diptera: Cecidomyiidae - gall midge Cystiphora sonchi Gall on Sonchus arvensis, Perennial Sow-thistle Hosts: Sonchus arvensis, asper, oleraceus Often numerous raised circular pustules on upperside of leaves, initially green becomig purplish. Slightly concave blotch on underside, the whitish larva clearly visible. At least two generations a year, pupating in a white cocoon either in the gall or in the soil Similar: Cystiphora leontodontis occurs on Hawkbits, Leontodon crispus, hispidus and Scorzoneroides autumnalis (L. autumnalis) C.taraxaci on Taraxacum not yet recorded in Britain and Ireland

Cystiphora sonchi
Liliput, Dorset. July 2018