Spruce budworm has more or less completed its feeding for this year in Atlantic Canada and has shifted into the adult moth stage to mate and lay eggs for the next generation. Migration of adult moths during this stage is often prolific and considerable research has been dedicated to understanding how these migratory events influence outbreaks. However, less is known of the migratory activity of spruce budworm as populations rise. In particular, it remains uncertain what conditions prompt moths to migrate away from (or to) a particular area, the importance of male vs. female migration, or how much these migratory activities contribute to the spread and rise of spruce budworm outbreaks.
Trapping of spruce budworm moths across broad regions is often used to provide evidence for large-scale migratory events. The most common trap used is the pheromone trap (aka Multi-pher trap), which employs a synthetic version of the female’s sex pheromone to attract and capture spruce budworm males. Other options for adult trapping are the light trap, which attracts and traps a variety of moth species, and the malaise trap, which passively captures spruce budworm moths (as well as other insects) as they fly through the forest canopy.
In the context of our ongoing Early-intervention strategy project, we are currently using these trapping methods to monitor regional patterns of spruce budworm moth activity. These traps are being used to monitor moths throughout New Brunswick and south-eastern Quebec, to examine migration (or reinvasion) of moths into our Mimic-treated blocks and throughout the region. A side benefit of these traps is that there are often also other insects captured that may be used to provide evidence of non-target impacts of treatments on other moth species and parasitoids.
Moth activity can be somewhat protracted due to regional differences in the emergence of moths, so it is quite likely that this moth monitoring will continue until at least mid-August. During this period eggs will probably begin hatching and the next phase of the spruce budworm life cycle will begin, as will the next phase of our project.