Persistence of the Nuclear Polyhedrosis Virus of the Rice Swarming Caterpillar Spodoptera mauritia (Boisduval) in Soil

Persistence of the nuclear polybedrosis virus (NPV) of Spodoptera mauritia (Boisduval) in soil was studied. The virus when incorporated in soil and kept under field conditions had a half life of 6.46 months, while it was 16.03 months for the virus in soil kept under laboratory conditions. A comparison of the LT₅₀ values showed that the virus lost its virulence more rapidly when the virus treated soil was kept outdoors. The virus stored in a refrigerator showed only slight loss in original activity even after 18 months.