Biochemical identification and comparative insecticidal activity of nucleopolyhedrovirus isolates pathogenic for Heliothis armigera (Lep., Noctuidae) larvae

Publisher Website
Google Scholar
Abstract
Three Nucleopolyhedrovirus (NPVs) originally isolated from Heliothis armigera larvae, collected from Portugal (HearNPV‐PO) and two places in Spain (HearNPV‐SP1 and HearNPV‐SP2), and three previously described NPVs were compared biochemically and biologically. Restriction endonuclease analysis of the virus genome with several enzymes revealed that isolates HearNPV‐SP1 and HearNVP‐SP2 are unique but closely related genotypes which represent two new strains of the NPVs of H. armigera. The DNA fragment profiles of HearNPV‐PO were distinct from those of the HearNPV‐SP1 and HearNPV‐SP2, with all the enzymes used, while they were identical to the Mamestra brassicae NPV strain present in the commercial product MAMESTRIN®. Bioassays in third‐instar H. armigera larvae showed that the LD50 value obtained for HearNPV‐SP1 (68 occlusion bodies/larva) was about two‐ and six‐times lower than those of HearNPV‐SP2 and a Russian isolate, HearNPV‐RU, respectively. The corresponding LT50 values were not found to differ significantly between these three virus isolates at comparable doses.