Transmission of Nuclear Polyhedrosis Virus Prior to Death of Infected Loblolly Pine Sawfly, Neodiprion taedae linearis Ross, on Loblolly Pine

Nuclear polyhedrosis virus (NPV) was transmitted by infected loblolly pine sawfly, Neodiprion taedae linearis Ross, larvae prior to death on loblolly, pine. Third instars reared on pine foliage previously fed upon for 24 h by NPV-infected larvae at densities of 4 and 16 per terminal resulted in up to 69.9 and 93.1% mortality, respectively, in previously unexposed cohorts. Third instars reared on pine foliage wetted with washings from frass of infected larvae also resulted in a high level of mortality. Results suggest that a high level of secondary transmission of NPV occurs before death of primary-infected larvae. This transmission appears to be the result of NPV in the digestive tract released either through regurgitation or in the feces.