Yellow-poplar, Liriodendron tulipifera L., also known as the tulip-poplar, is an important source of pulpwood and saw timber, and it is widely used as a shade tree. Numerous insect species attack the foliage of yellow-poplar. In 1965, Odontopus calceatus (Say) was first observed seriously damaging yellow-poplar in Tennessee (Russell and Stanley 1967). Defoliation was so severe at the University of Tennessee Oak Ridge Forest Experiment Station that growth reduction was attributed to this pest (Buckner 1972). In 1967, observations by one of us (E.A.H.) indicated that several other insects attack yellow-poplar leaves during the spring. Infestations of the aphid Macrosiphum liriodendri (Monell) and gall midges, Cecidomyia sp. and Thecodiplosis liriodendri Osten Sachen, were common. Cecidomyia sp. was called tulip vein gall, and T. liriodendri tulip spot gall, by Felt (1940), who described their damage. Since no measures had been determined for their control, a series of tests was conducted to determine the efficacy of various insecticide treatments