PCNA and infection: AcMNPV nucleocapsids can be transported into the nucleus through a nuclear pore [27] via interaction with actin/P78–83 [4,6], while this mechanism may not involve the entry of BmNPV into host and non-host cells, this may result from the absence of some AcMNPV genes in BmNPV genome [3], such as pcna, host cell-specific factor 1, ac134, it explains why low-pH triggering is not sufficient for BmNPV infection.