Contarinia cucumata Gagne, new species

Hosts: Carya ovata, tomentosa, pallida, cordiformis, glabra

Gall (Figs. 29, 172-174): Infrequent, on Eucarya and Apocarya sections; on lower leaf surface, adjacent to vein; 3.6-5.0 mm in length, constricted at point of attachment to leaf, cylindrical and decumbent beyond, convex apically, not dehiscent; surface rough, green becoming yellow, then brown, with many scattered, long, fine, white hairs not obscuring surface; base initially crimped, opening to upper surface of leaf when mature; wall thin, at first soft, later brittle, larval chamber rough.

Affinities. — Larvae of Caryadiplosis venicola, also on hickory, are generally similar to this species, but young third instars of C. venicola have rounded spatula teeth while those of C. cucumata have pointed teeth. Contarinia cucumata is further distinguished by the complex gall it causes; most Contarinia spp. make no gall or simple ones, such as leaf rolls.

Biological notes. — This species shows wear of its spatula while still in the gall. Figs. 339-340 show the spatula of a newly molted third instar and an older one. The spatula of the newly molted larva is not yet entirely hardened or pigmented. In central Md, galls were first noticed on May 23 when still only bubble-like and containing first instars. Galls were greenish white to light green, somewhat sticky, and covered with close, long white hairs. In subsequent days these hairs became farther apart as the gall quickly elongated along the leaf axis and became darker green. Larvae developed quickly and began to leave the galls by June 9 through the newly opened exit aperture on the upper side of the leaf. Mature larvae are white and active.

Range: AL, GA, KY, MD, MS, MO, NY, OH, TN, VA, WV

- Raymond J. Gagne: (2008) The Gall Midges (Diptera: Cecidomyiidae) of Hickories (Juglandaceae: Carya)^©

Reference: https://www.biodiversitylibrary.org/page/38636615#page/98/mode/1up