Farmers reported that 18.6 million pounds (a.i.) of herbicides and 23.2 million pounds of defoliants and desiccants were applied to cotton during 1979. Herbicide acre-treatments totaled 22.9 million and consisted of 20.5 million with single material herbicides, and 2.4 million with herbicide mixes. Defoliant and desiccant acre-treatments totaled 9.2 million and consisted of 8.1 million single material defoliants and desiccants and 1.1 million tank-mixes. The major herbicides were fluometuron, glyphosate, MSMA, and trifluralin. The primary defoliants and desiccants were arsenic acid, DEF, paraquat, and sodium chlorate. Coefficients of variation were computed for acres treated with specific pesticides.