Farmers reported that 33.3 million pounds (a.i.) of pesticides were applied to field corn in the Northern Plains during 1980. This consisted of 23.7 million pounds (a.i.) of herbicides and 9.6 million pounds (a.i.) of insecticides. Pesticide acre-treatments totaled 23.1 million and consisted of 9 million with single material herbicides, 3.6 million with herbicide mixes, and 10.5 million with insecticides. The primary herbicides were alachlor, atrazine, and 2,4-D. The major insecticides were carbofuran, dimethoate, fonofos, parathion, and terbufos. Herbicides were applied primarily to control cocklebur, foxtail, and pigweed infestations, while insecticides were mainly used for Banks grass mite, corn borer, and corn rootworm larvae control. Coefficients of variation were computed for acres of field corn treated with specific pesticides.