It’s another busy season for the Forest Pest Management group (FPMG) at the Department of Energy and Resource Development (ERD). Our staff once again is taking to the roads and woods of NB to set up 300 pheromone traps across 100 sites throughout the province. These traps aid in the early detection of spruce budworm population growth and movement, and in some cases, can help identify large-scale dispersal events if and when they occur (you can find out more on that here.
Detecting Budworm Defoliation
In late June, we will start to map signs of spruce defoliation from the air during our annual aerial survey. A small team from FPMG will survey from a small aircraft in sweeping transects of northern NB in search of the characteristic red needles left behind by budworm feeding. At the same time ground crews will drive the vast network of forest roads looking for more subtle signs of budworm defoliation that our aerial crews might not be able to detect, all told ~10,000km to be traveled in three short weeks!
This annual work helps to indicate the areas where populations might be established and rising even when our other methods don’t find any insects. In 2016, these surveys revealed several small pockets of trace-to-light defoliation, localized near the borders of Quebec. A positive sign that budworm have not yet established large feeding populations in NB.
Estimating the Budworm Population
Mid-August marks the time to start collecting our pheromone traps. At this time, moth activities are almost complete for the season and the L2 (2nd Instar Larvae) survey is set to begin. To make for a more efficient task, pheromone traps are collected during the L2 survey and moths are counted back at the lab. In 2015 and in 2016, northern NB had the highest number of moths caught, while almost all areas monitored in southern NB had low numbers of moths.
The 2016 L2 survey involved the collection and analysis of ~1600 sites, which works out to almost 4800 branches. These branches were collected by partners in the Healthy Forest Partnership including the FPMG, industry partners and this year, ERD staff joined the efforts. Although the keen eye will think these numbers are a reduced effort from last year, they don’t account for the ~1000 branches that were processed in the brand new CFS lab facilities that would typically also have gone through the FPMG lab.
All this work takes several months to complete and the work doesn’t stop once the surveys are done. As soon as the data is entered, members of the ERD use it in combination with information about the forest composition and other important factors develop the models that prioritize budworm treatment areas for the following season.