Introduction. The Baculoviridae is a diverse family of pathogens that are infectious for arthropods and are characterized by a complex replication cycle that culminates in the occlusion of virions in a crystalline protein matrix (Blissard & Rohrmann, 1990). Over 400 lepidopteran species serve as hosts for these viruses, with a single virus isolate usually restricted to one or a few related species. In addition, they have been reported from species of the orders Hymenoptera, Diptera, Siphonoptera and Trichoptera, as well as in several crustaceans (Adams & McClintock, 1991; Martignoni & Iwai, 1986). Baculoviruses are divided into two genera based on occlusion body morphology; the nuclear polyhedrosis viruses (NPVs) (Rohrmann, 1994), which are characterized by many virions present in each polyhedron-shaped occlusion body, and the granulosis viruses (GVs) (Crook, 1994), which normally have smaller occlusion bodies each containing only a single virion, and have been reported to infect only the Lepidoptera.