ARS | Publication request: YIELDS OF OCCLUSION BODIES FROM HELIOTHIS VIRESCENS AND HELIOTHIS ZEA LARVAE FED WILD OR RECOMBINANT STRAINS OF HZSNPV AND ACMNPV

Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 21, 2000
Publication Date: N/A

Interpretive Summary: Naturally occurring viruses that kill insect pests can be used as safe, effective biopesticides. The effectiveness of these viruses can be further enhanced by genetically modifying them to kill the insect pest more quickly. Initial observation, however, indicated that some of these genetically modified strains produced less virus than the native strain. Our efforts were to determine the extent of this production loss. We foun that virus production from the genetically modified viral strains was approximately 2- to 10-fold lower than that of the native strains. Commercial producers might anticipate lower yields from genetically modified viruses and consider the possible impact of this reduction on product cost and effectiveness.

Technical Abstract: Larvae of Helicoverpa zea and Heliothis virescens fed recombinant strains (Rc) of two nucleopolyhedroviruses (AcMNPV, HzSNPV), genetically engineered to express insect specific scorpion toxin, produced significantly lower numbers (1.6 to 10.3-fold lower) of occlusion bodies (OB) than larvae infected with the wild strain (Wt) of these viruses. Lower yields of OB was a manifestation of early larval paralysis of all toxin-expressing Rc strains.