Ribesia sarae

A recently discovered new species of gall midge (Diptera: Cecidomyiidae) that forms simple blister galls on golden currant, Ribes aureum Pursh (Grossulariaceae), in Montana, USA, is described here.

This record of a blister gall on leaves of Ribes is not the first for North America or for R. aureum. Felt (1911) listed an “irregular, dark brown blister gall, diameter, 3 mm.; on R. longifolium” [error for R. longiflorum Nutt., now a junior synonym of R. aureum]. Felt later (1918) listed the gall as an “irregular, greenish or dark brown blister gall, diameter, 3 mm.; on R. longiflorum, also on Grossularia inermis” [now Ribes inerme Rydb.]. The galls were found in Colorado. Such galls are presumably widespread in western North America and may also occur on many of the 50 or so species of American currants.

Full-grown larvae were found VII-17-2014 in individual blister leaf galls on Ribes aureum growing along the Missouri River in Great Falls, Montana. The galls were yellowish, elliptical, about 3 mm in diameter, and barely thicker than normal leaf tissue. When the galls were found, many larvae were actively exiting from them through a slit in the thin tissue covering the gall on the upper side of the leaf. Leaves were collected and placed in a quart-size plastic bag and the end knotted closed. Several days later, larvae that had by then all exited the galls, were transferred to a pot filled with damp peat moss and kept until the following spring. Adults emerged in March 2014. From this it would appear that R. sarae is univoltine. 

A New Genus and Species of Cecidomyiidae (Diptera) from Leaf Blister Galls on Ribes (Grossulariaceae) in North America