Heliothis spp. are clearly the major pests of Australian cotton and consequently there has been considerable research on their biology, ecology and control (Zalucki et al 1986). Most of this research has focused on Heliothis populations on particular crops within cropping areas. However, these species are not restricted to crops and exploit a wide range of non-cultivated host plants within and outside the cropping areas, in addition to their many cultivated hosts.