Abstract Six commercially-available surfactants/ wetting agents were compared to determine their toxic effects on beet armyworm and fall armyworm larvae. Larvae used in this study were obtained from the USDA-ARS Insect Biology and Population Management Research Lab in Tifton, GA, and were 4-days-old on the day of treatment. Surfactants were mixed in water at the rates of 0, 1, 3, 5, 10 and 15% of the total volume. Larvae (10 of each species/surfactant rate) were placed individually into 30 ml plastic cups containing 10 ml of bean diet. Surfactant/water mixes were then applied to the dorsal surface of each larva at the rate of 10 u,l/larva. Diet cups were capped and placed in an environmental chamber at 24° ± 2°C, 50 ± 5% RH, and 12:12 (light-dark) photoperiod. After 24 h the number of live and dead larvae were counted for each surfactant rate. These experiments were repeated three times. Data were analyzed using the POLO-PC Probit procedure (LeOra Software, 1987).