Replication of Nonoccluded Baculovirus Associated with the ParasitoidMicroplitis croceipes(Hymenoptera: Braconidae) inHeliothis virescens(Lepidoptera: Noctuidae)

Replication ofMicroplitis croceipesnonoccluded baculovirus (McNOBV) inHeliothis virescens(F.) larvae was detected by double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), transmission electron microscopy (TEM), and bioassay. Five-day-old (early third instar)H. virescenslarvae were inoculated intrahemocoelically with 0 (control), 3, or 30 ng virus/larva, subjected to ELISA, and verified by TEM, at various hours after inoculation. The ELISA results showed increases of the absorbance values and the amount of virus particles produced in some inoculated larvae. McNOBV infection was observed in 16.7–33.3 and 66.7–83.3% of larvae inoculated with 3 and 30 ng virus, respectively, 24–96 h post inoculation. Virus particles were detected in hemolymph, fat body, and midgut epithelial cells of infected larvae. In bioassay, when McNOBV-infected larvae were exposed to healthy, premated, femaleM. croceipes(Cresson) for oviposition, 10.6% of theM. croceipesfemales became infected with the virus. Examination ofM. croceipesoffspring indicated significant decreases (control vs. infected) in larval emergence (75.0 to 39.6%), cocoon formation (68.8 to 31.3%), and adult eclosion (68.1 to 22.2%). McNOBV was detected by ELISA in 25.9% of dead larvae, 45.2% of dead pupae, and 37.3% of the surviving adults ofM. croceipes.These results demonstrate that McNOBV replication inH. virescenslarvae and transmission of McNOBV from infectedH. virescenslarvae to ovipositingM. croceipesfemales and their offspring can occur.