In this communication we report the infection of armyworm Spodoptera frugiperda IPLB-Sf21 cells with Anticarsia gemmatalis multicapsid nucleopolyhedrovirus at low multiplicity of infection (MOI).The temporal variation of the extra-cellular virus and of the unstained cell was followed. The series of peaks in the virus concentration and the unstained cells count were used in order to infer the dynamic mechanism of the infection at low MOI. This mechanism can be used as the basis for the future formulation of a mathematical model of the process.