B. J. Cooke, J. Régnière
Natural Resources Canada, Canadian Forest Service
SERG Project #1999/05
Year of Project: 2004
Report Received: 2006
This project was designed to test whether high-density populations of spruce budworm moths exhibit local-scale diffusive patterns of movement back into spray blocks after foliage has been protected from larval feeding by B.t. spray. Spray treatments were highly effective at reducing population densities within all three treatment blocks; however population densities collapsed in the surrounding untreated buffer areas as well - presumably as a result of natural enemies, and possibly in combination with delayed phenology associated with cold summer weather. Despite intensive branch sampling, extremely low numbers of pupae and eggs were encountered both inside and outside the spray blocks, making it impossible to get a precise estimate of the ratio of eggs to moths. Thus we were unable to detect any reinvasion events, and we were unable to estimate the amount of moth movement over various distances into the spray blocks.