Heliothis zea (Boddie), the corn earworm (CEW) and Heliothis virescens (Fabricius), the tobacco budworm (TBW), are primary pests of corn and tobacco, respectively, but attack numerous other agricultural crops. The two species are known as the Heliothis or bollworm complex when they concurrently attack cotton. Under such circumstances, losses to the cotton crop plus expenses incurred in efforts to obtain acceptable insecticidal control are estimated generally to cost 2-3% of the total value of the cotton crop annually.

Both species have evolved a diapause mechanism that allows them to overwinter as pupae in the soil. Both species have more preferred hosts than cotton and are capable of developing quite expanded late spring-early summer populations on those hosts prior to moving into cotton.in the last few years, studies have been conducted to better understand these host-pest relationships and the subsequent movement of the pest into cotton. The host-pest relationship of corn and the CEW and movement of the CEW following development on corn has been studied more intensively; thus, the CEW is used as the example insect in this paper to examine the importance of late spring and early summer bollworm moth migration into Texas and delta cotton growers' cotton.