Direct observation and radiolabeling techniques were used to investigate movement and burrowing activity of prepupalHeliothis zea(Boddie) released in the field. Microenvironmental conditions as a function of tillage method influenced prepupa behavior differently in successive years. In a moist year, prepupae tended to burrow closer to the release site in no-tillage plots than in conventionally tilled plots; in a dry year, this trend was reversed. Distance that prepupae moved on the soil surface and time they required for burrowing were influenced by both soil type and moisture conditions. Overall, prepupae traveled greater distances and spent more time on the soil surface when the soil was smooth or crusted. Ant attacks were more frequent on prepupae in no-tillage treatments than in conventional tillage. A field cage study revealed no differences in survivorship between insects released in the two tillage treatments.