Application of balsam fir sawfly nucleopolyhedrovirus against its natural host Neodiprion abietis (Hymenoptera Diprionidae

Abstract -Fifty-hectare blocks of balsam fir forest, in western Newfoundland Canada, were treated with 1 -3 x 10 9 occlusion bodies/hectare of Neodiprion abietis nucleopolyhedrovirus (NeabNPV) in 2.5 L 20% aqueous molasses using Cessna 188 'Ag Truck' airplanes equipped with Micronaire AU 4000 rotary atomizers. In the weeks following application, there was higher balsam fir sawfly larval mortality in the spray blocks than in the control. In the subsequent year, there was lower percentage egg hatch and higher larval mortality in samples collected from the spray blocks compared to those from the control block. Balsam fir sawfly pupae with white as opposed to brown pupal cases were significantly more like to harbour NeabNPV infection. These results suggest that aerial applications of NeabNPV can suppress outbreaking balsam fir sawfly populations