Infestation Patterns and Climate-Based Projections for European Spongy Moth (Lymantria dispar) in Whirlpool Forest, Ontario, Canada

This study investigates spongy moth (<i>Lymantria dispar</i>) infestation patterns in Whirlpool Forest, Ontario, offering a region-specific perspective while largely corroborating existing findings. We analyzed egg mass distribution across 43 sampling plots, relating it to tree characteristics. Results revealed a preference for red oak species, with significant egg-laying above one meter. Positive correlations were found between tree diameter and egg mass quantity (<i>ρ</i> = 0.458, <i>p</i> < 0.001 above 1 m; <i>ρ</i> = 0.218, <i>p</i> = 0.006 below 1 m). Tree health was significantly associated with egg mass presence (<i>χ²</i> = 6.08, <i>p</i> = 0.014). A climate-based regression model (<i>R²</i> = 0.714, <i>p</i> < 0.05) projected substantial increases in outbreak area by 2100, with the most severe scenario predicting 9,927,378.49 hectares at risk. Sensitivity analysis showed a 1 °C temperature increase could expand the outbreak area by 814,100 hectares. These findings underscore complex infestation dynamics, challenging simplified models and emphasizing the need for tailored, adaptive forest management strategies in response to changing environmental conditions and pest behaviors.