Baculoviruses constitute one of the largest and most diverse groups of insect pathogenic viruses. Numerous experimental field trials between 1950 and 1960 demonstrated the usefulness of baculoviruses as viral insecticides; however, with the concurrent advent of numerous synthetic pesticides with broad-spectrum, low cost, and high insecticidal activity, viral insecticides failed to become a commercial success. During the late 1970s and throughout the 1980s, it became clear that the overdependence on chemical pesticides for pest control created numerous unacceptable agricultural, environmental, and human-health problems. The paper examines the current status of pesticidal baculoviruses, their genetic improvement, and the field-release testing of modified viruses.