Detection, characterization and virulence analysis of nucleopolyhedrovirus isolated from the cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

Abstract Background In the present study, detection, characterization and virulence analysis of a field collected nucleopolyhedrovirus isolated from cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) was carried out. The obtained isolate, named SpliNPV-YW, diseased S. larvae in El-Menoufia governorate, Egypt. Results Transmission electron microscopy showed presence typical occlusion bodies with average size (1.06 × 1.19 µm). Upon digestion using two different endonucleases, Ps tI Sc aI, no clear difference detected isolate (SpliNPV-YW) DNA genome pattern compared to reference strain SpliNPV-AN1956. evolutionary polyhedrin gene's partial nucleotide sequence revealed that SpliNPV-YW closed had genetic origin NPV SpliMNPV-A26-5 belongs group II NPVs identity 99.7%. median lethal concentration (LC 50 ) time (LT values were estimated for second fourth larval instars . LC 2.8 10 4 OB/ml instar 5.2 5 after days treatment. Regarding speed killing viral results LT value = 5.5 days) lower than 6.2 at concentrations 4.3 (ob/ml) 1.2 11 larvae, respectively. Conclusions Host specificity characteristics make good potential be utilized as candidate biopesticide control population