During our survey we also encountered a gall midge (Schizomyia macrofila) that feeds on fiddleneck and produces galls. Galls formed by the larvae are superficially similar to those formed by the nematode (Anguina amsinckia). However, the midge galls do not replace the flowers as do the nematode galls. Instead, almost any aboveground portion of the weed may form midge galls containing one or more orange-colored larvae.

Few researchers have studied this gall midge, and its host range is not certain. Before our survey, only Amsinckia lycopsoides was reported to be a host. We found the midge on A. intermedia near Bakersfield and on A. spectabilis near Bodega Bay.

Amsinckia
Spherical, soft swellings on inflorescence, stem, or leaf...Schizomyia macrofila (Felt)
Adults emerge in spring and lay eggs directly into plant tissue. Galls grow to 3-15 mm in diameter. One to six larvae develop swiftly in each gall and drop to the soil when full-grown...Hosts: A. intermedia, A. lycopsoides, A. spectabilis...