Field tests were used to evaluate the efficacy of liquid acephate in aerial applications to control grasshoppers on rangeland. An antidrift additive applied with the treatment was also evaluated. A rate of 105 g AI/ha of acephate at volumes of 2337, 1899, and 1461 mL of mix/ha with the addition of Nalco-trol® resulted in control statistically as good as the standard malathion treatment of 653 g AI/ha. Two formulations of acephate applied at the rate of 105 g AI/ha in a volume of 2337 mL/ha were compared and resulted in statistically comparable mortalities; both formulations of acephate resulted in excellent control 10 days after treatment.