To provide a material for controlling a pest insect, exhibiting the pest insect-controlling effects against Mamestra brassicae and Helicoverpa armigera.

Wild nuclear polyhedrosis viruses of a tobacco cutworm living in Japan are classified to three types of A to C. The three types of the viruses are distinguished by each different electrophoretic pattern caused by the cleavage assay of a genome DNA by a restriction enzyme using EcoRI restriction enzyme. The material for controlling the pest insect contains a type C nuclear polyhedrosis virus of the tobacco cutworm. The type C virus provides a DNA fragment having the length of 16 kbp, and does not provide a DNA fragment having the length of 4.7-5.9 kbp, recognizable when the genome DNA is cleaved by the EcoRI restriction enzyme. The type C virus has the insecticidal activities against not only the tobacco cutworm and Spodoptera littoralis, but also the larvae of the Mamestra brassicoe and the Helicoverpa armigera.