The aims of the CRDC project CSE 29C were: - to optimise the design of recombinant Helicoverpa viruses with increased insecticidal activity (Activities 1 and 2 of the overall program above), - to develop suitable large-scale production systems (Activity 4) and - to assess the potential impact recombinant viruses may have upon the environment (Activity 5). Timescales for the overall program are shown in Figure 1. Objectives for each year of the CRDC project