A number of inhibitors of DNA, RNA, protein and polyamine synthesis have been used to elucidate the mode of replication of baculoviruses. An overview of the viruses, the antimicrobial inhibitors used, and the effects of the drugs are presented. Although certain inhibitors of protein synthesis and DNA synthesis are useful in determining the program of expression of the viral genome into immediate early, delayed early, late and very late phases of synthesis, few drugs have proved useful as antimicrobial agents. Bromovinyldeoxyuridine (BVDU) is a potent inhibitor of baculovirus replication inhibiting viral DNA synthesis by blocking the virus induced DNA polymerase. Preliminary experiments suggest that BVDU suppresses baculovirus disease in insect larvae.