Comparison of the Activities of Three LdMNPV Isolates in the Laboratory Against the Chinese Strain of Asian Gypsy Moth

ABSTRACT

Three isolates of gypsy moth [Lymantria dispar (L.)] nucleopolyhedrovirus (LdMNPV), from China (LdMNPV-H), Japan (LdMNPV-J) and the registered strain from North America (LdMNPV-D), were bioassayed in the Inner Mongolia Autonomous Region, People’s Republic of China, in 2004, using a modified version of the diet plug method, to determine their pathogenicity and virulence based on the dose- and time-response of second-instar larvae of the Chinese strain of the Asian gypsy moth. Results showed that LdMNPV-H and LdMNPV-D did not differ significantly in dose-response. The LD50 and LD95 for LdMNPV-H were 211 and 1414 OBs larva-1, respectively, while LdMNPV-D had a somewhat lower LD50 (194 OBs larva-1) and a higher LD95 (1705 OBs larva-1). LdMNPV-J was the least pathogenic, with a LD50 of 940 OBs larva-1 and LD95 of 11 457 OBs larva-1. Overall, LdMNPV-H and LdMNPV-D had similar pathogenicity against second-instar larvae of the Chinese strain of the Asian gypsy moth, and were considerably more pathogenic than LdMNPV-J. Time-responses were not significantly different among the three virus strains.