The present paper reports proceeding on host range determinant of insect baculovirus over the past ten years. It has been found that viral entry into host cell is not the major limiting factor for baculovirus host range because baculovirus is able to enter a wide variety of animal hosts such as nonpermissive insect cell lines

insects and mammalian cell lines. Although early promoters of baculovirus are active in a wide variety of insect hosts

late and very late promoter are active only in permissive insect cells. Gene expression from late or very late promoters may be critical to baculovirus host range. In the 18 viral genes which are necessary and sufficient to support late and very late gene expression

helicase gene (p143) and apoptosis suppressing gene (p35) have been implicated as host range determining genes.