<i>In vivo </i>enhancement of nucleopolyhedrovirus of oriental Armyworm, <i>Mythimna separata </i>using spindles from <i>Helicoverpa armigera</i> entomopoxvirus

Abstract

When the third instar larvae of <i>M. separata </i>were exposed to eight varying concentrations of polyhedral occlusion bodies (POB's) of nucleopolyhedrovirus of <i>M. separata </i>(MsNPV)

ranging from 2.6×10¹ to 2.6×10⁸ POB's/ml, the percent mortality and incubation period ranged from 16-100% and 14 to 9 days respectively. On the other hand when the same third instar larvae of <i>M. separata </i>were exposed to only five varying concentration of POB's of MsNPV ranging from 2.6×10² to 2.6×10⁶, POB’s/ml along with a constant dose of entomopox viral spindles from <i>Helicoverpa armigera, </i>the per cent mortality ranged from 63 to 100% with reduction in incubation period from 7 to 4 days respectively. The enhancement index (log₁₀) of the virus was 2.76 or reduction of more than 500 times in LC₅₀. The ability and the mechanism of the spindles from <i>H. Armigera</i> entomopoxvirus to enhance the infectivity of MsNPV has been discussed.