April and May of 2014 have been busy months as we prepare for the upcoming spruce budworm studies in northern New Brunswick, about 60 km north of Edmundston (aka Hornes Gultch). This is the first region in New Brunswick where provincial surveys have detected more than a few overwintering spruce budworm larvae. The apparent rise of spruce budworm in this region is perhaps an indication of where the New Brunswick outbreaks might begin.
Although it was clear that spruce budworm had risen somewhat in the area, we were still uncertain how large and widespread the population was. To carry out some additional surveys, our field crew braved the snow, sleet, and cold in early April on snowmobiles and snowshoes (Picture 1). In total, we sampled 180 branches using pole pruners (Picture 2) and found 121 spruce budworm larvae. In the context of a full-on spruce budworm outbreak this density is still quite low – we would struggle to even detect defoliation at these population densities. To put this number in more perspective, some of the “high density” spruce budworm sites in Quebec have been known to have as many as 100-300 larvae on a single branch! Even still, the numbers in Hornes Gultch are much higher than what we have seen at any time in New Brunswick during the past 35 years (i.e., since the last spruce budworm outbreak). The central theme of our research is to determine if managing such low density populations before they reach epidemic levels could allow us to slow the spread of the outbreak (Research Overview).
The next step will commence in early June and will involve sampling of middle-aged spruce budworm larvae (as well as other insects) in our study sites.