A positive role in the spread of viruses on the leaves can be played by parasitic and predatory insects, which come in contact with dead larvae, take over the polyhedra on their bodies and spread them in the host's biotope. Phytophagous insects were used for research: Mamestra brassicae and Heliothis armigera. As an experimental material served biological baculoviral preparations based on the genus Baculoviridae family that differ from other biological preparations, have an epizootic character and transmit the pathogen vertically and horizontally in decreasing populations of harmful insects from one generation to another through their selectivity.