The bollworm, Helicoverpa zea (Boddie), and the tobacco budworm, Heliothis virescens (F.), are major pests of many row crops throughout the United States. These pests annually cause economic damage to non-transgenic cotton across the mid-South of the United States. From 1986 through 2005, adult pheromone traps located in Washington County, Mississippi, were used to estimate populations of both species in the Mississippi Delta. From 1986 through 1996, moth captures for both species fluctuated yearly, but typically more moths of H. virescens were captured than H. zea. Since 1997 more moths of H. zea than of H. virescens were captured each year, and adult populations of both heliothines have declined annually. This decline in adult populations of H. virescens has been dramatic, especially over the last 5 years. The decline in H. virescens may be due to wide-scale plantings of Bt cotton. Other factors that may have impacted populations of H. virescens and H. zea in the Mississippi Delta are discussed.