Georgiaphis ulmi (Wilson)

Gall is formed by curling one edge of the elm leaf into a spindle shape, 2-5 cm long. Galled leaves turn yellow, then red, then drop off (Wilson 1911). Fundatrix reddish-brown. Monoecious holocyclic, and apparently specific to Ulmus alata. Alate sexuparae, reddish brown with black head and thorax, are produced in second generation (Wilson 1911), leaving galls in May-June. In eastern North America.

- Roger Blackman, Victor Eastop: (2013) Aphids on the world's plants^©

Reference: http://www.aphidsonworldsplants.info/d_APHIDS_G.htm#Georgiaphis