Male antennae of Phyllophaga tristis (Fabricius) (Coleoptera: Scarabaeidae: Melolonthinae) were tested using a coupled gas chromatograph-electroantennogram detector (GC-EAD) system for electrophysiological responses to five sex pheromones identified from other Phyllophaga species including L-valine methyl ester, L-isoleucine methyl ester, L-leucine methyl ester, methyl 2(methylthio)benzoate and methyl 2-amino benzoate. Male antennae responded only to methyl 2(methylthio)benzoate. In a 2003 field test near Greensburg, Kansas, cross-vane traps baited with rubber septa containing 1 mg of methyl 2-(methylthio)benzoate captured 466 male P. tristis. Control traps baited with rubber septa loaded with only hexane captured none. Similarly, in a field test in 2010 in Gainesville, Florida, 265 male P. apicata Reinhard were captured in traps baited with 1 mg of methyl 2-(methylthio)benzoate whereas control traps captured only a single male.