The granulosis virus (GV) of sugarcane shoot borer,Chilo infuscatellusSnelt., was found to be transmitted vertically when the fourth instar larvae were microfed with the virus at a sublethal dose of 1.1 x 103inclusion bodies/larva. The virus infection was found to alter the sex ratio in pupae in favour of male (1 : 5.70—♀ : ♂) from the normal 1 : 1 ratio. The per cent pupation and adult emergence were also significantly reduced. No adults emerged from abnormal pupae that lacked pigmentation on the ventral surface of the first abdominal segment. The GV was also found to be transmitted from the infected adult to the offspring through eggs and 50% of the larvae that hatched were found to die due to virosis.