In the American Midwest, summer fires are infrequent, and there is little information on their impact on ecosystems. After an accidental wildfire in a 20 ha grassland restoration, new growth provided effective substrate for the noctuid species corn earworm, Helicoverpa zea (Boddie), and tobacco budworm, Heliothis virescens (Fabricius). These agricultural pests feed on a number of important crop species and have been implicated in crop losses of up to 50 %. Invertebrate collections were made at 16 days, 45 days, 70 days, and 101 days post fire. A comparison of burned and unburned areas at 70 days post fire show 18 times the number of Lepidoptera larvae collected in pitfall traps in the burned area compared to the adjacent unburned area of the grasslands. These findings demonstrate that a mid-summer fire can affect the abundance of economically important insects.