Galls may form by the activity of the creosote gall midge. A large number of gall midge species are natural enemies of other crop pests. It is known by the common names of daylily gall midge and hemerocallis gall midge. The Asian rice gall midge is a fly about the size of a mosquito. A gall midge, "Rhopalomyia astericaulis", produces a stem gall on this species. Rabdophaga iteobia is a gall midge which forms galls on the buds of willow species. Iteomyia capreae is a gall midge which forms galls on willows ("Salix" species). Iteomyia major is a gall midge which forms galls on willows ("Salix" species). A gall midge, "Contarinia negundinis" joins and enlarges the galls of "Aceria negundi".