Farmers reported that 144.8 million pounds (a.i.) of pesticides were applied to field corn in the Corn Belt during 1980. This consisted of 127 million pounds (a.i.) of herbicides and 17.8 million pounds (a.i.) of insecticides. Pesticide acre-treatments totaled 75.5 million and consisted of 43.6 million with single material herbicides, 15.7 million with herbicide mixes, and 16.2 million with insecticides. The primary herbicides were alachlor, atrazine, butylate, and 2,4-D. The major insecticides were carbofuran, fonofos, and terbufos. Herbicides were primarily applied to control cocklebur, foxtail, and velvetleaf infestations. Most insecticides were used for corn rootworm larvae control. Coefficients of variation were computed for acres treated with specific pesticides.