The gypsy moth (Lepidoptera: Lymantriidae) nucleopolyhedrovirus as a synergist for baculoviruses against beet armyworm, fall armyworm and corn earworm (Lepidoptera: Noctuidae)

The gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae) nucleopolyhedrovirus LdMNPV was tested as a synergist for nucleopolyhedroviruses against Helicoverpa zea (Boddie), Spodoptera exigua (HObner), and Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) larvae. The addition of the gypsy moth NPV significantly decreased the LC(50)s of AcMNPV, AfMNPV, GmMNPV, HaMNPV, HzSNPV, PxMNPV, RoMNPV, SeMNPV, and SfMNPV. In the case of the corn earworm, H. zea, the most active virus was the homologous virus HzSNPV. The addition of LdMNPV increased the activity of HzSNPV by 8.7-fold. Whereas LdMNPV increased the activities of each NPV against H. zea, none of the combinations were as active as HzSNPV alone. The most active NPV against the beet arinyworm, S. exigua, was HaMNPV. AcMNPV and RoMNPV were comparable in activity with that of the homologous virus SeMNPV. The most active combinations against the beet armyworm were AfMNPV/LdMNPV and HaMNPV/LdMNPV, which were 7.5- and 4.4-fold more active that the SeMNPV/LdMNPV combination. The homologous NPV SfMNPV was the most active against fall armyworm, S. frugiperda, larvae, and the most active combination was SfMNPV/LdMNPV. These data indicate that the gypsy moth NPV could be used in combination with the homologous NPVs to increase the potencies of HzSNPV, SeMNPV, and SfMNPV against the corn earworm, beet arinyworm, and fall armyworm, respectively.