The bioinsecticidal activity of several doses of a Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV-CH-32; LD10, LD50, and LD90) and a Type I Spodoptera frugiperda granulovirus (SfGV-CH13; LD50 and LD90), alone and in co-infection, was evaluated on S. frugiperda larvae. The gene discussed is C4B; the disease is coinfection.