Thermal inactivation of the granulosis virus (GV) of Chilo infuscatellus Snellen occurred in the temperatures between 80 and 90°C. The pH 4 to 6 and 10 showed adverse effect on the virus infectivity and the ultraviolet light inactivated the virus completely within 20 minutes of exposure. The dry deposit of the virus was not inactivated as reddily as virus in aqueous suspension. The persistence of shoot borer GV was inversely related to the exposure time and the half life was found to be 6.8 days.