Factors to predict spongy moth reservoirs between outbreaks - historic outbreak severity and forest composition

-Dr. Emma Despland, Carly Ziter, Noa Davidai (Concordia University)

The spongy moth (Lymantria dispar dispar) is an invasive pest that can destroy trees by eating their leaves.  This moth is native to Europe but is now unfortunately found across Canada.  Outbreaks of this pest are cyclical, typically occurring about every seven to ten years. The most recent outbreak that peaked in 2021 was the largest on record in Ontario and Quebec.  During severe outbreaks, trees and shrubs are completely defoliated over large areas; despite the trees’ ability to produce a new crop of leaves over the summer, the damage causes substantial growth loss. Defoliation also makes trees more susceptible to secondary pests, drought, and poor growing conditions.  Combined with compounding stressors such as climate change, defoliation can be a significant stressor on trees and forest health.

Following the most recent outbreak of spongy moths, this project is investigating possible factors that may help predict spongy moth reservoirs between outbreaks.  The goal of the project is to determine if forest composition data (specifically the presence of oak trees) and historical spongy moth density data can help to predict locations of spongy moth reservoirs between outbreaks.

Stay tuned for results