From 1977 to 1979, mating disruption was tested as a method of controlling the lesser peachtree borer, Synanthedon pictipes (Grote and Robinson, and the peachtree borer, S. exitiosa (Say). Hollow fiber dispensers placed in each tree of a 24-ha peach orchard twice during each of the 3 seasons were at least as effective as the conventional insecticide treatment (applied to a second orchard of equal size) in suppressing population build up of the 2 species. Also, borer populations were lower in the pheromone treated orchard in all 3 years. Pretest trapping of males in 1976 showed that the 2 orchards had borer populations of about the same size. Three methods of evaluating the suppression produced results that paralleled each other. Mating disruption appears to be a feasible approach to control of peach borers.