Last week while working in our 2016 treatment blocks we took this picture of a balsam fir branch that helps to nicely illustrate the effectiveness of the bacterial insecticide Btk (Bacillus thuringiensis kurstaki) against spruce budworm. This particular branch was collected from an experimental site in the midst of ‘hot spot’ identified in 2014. While feeding wasn’t altogether halted in 2015 populations in the area were suppressed significantly for the next year, resulting in clean new growth for 2016 (see above picture). Of course, the Early Intervention Strategy doesn’t aim to suppress current season defoliation, by instead aims to diminishing populations in the following years. What we see in the picture above is what we should expect if our goal is to limit potential sources of moths that might otherwise seed new populations and thereby slow the southward spread of budworm through New Brunswick.
Emily Owens and Bernard Daigle