The Lymantria dispar dispar (LDD) moth is native to Europe. It was introduced to Massachusetts in the 1860’s, and quickly escaped into nature. The moth is a non-native invasive insect that was first found in Ontario in 1969. The first serious outbreak in Ontario was documented in 1981 in the Kemptville area.

This insect is a defoliator, meaning it eats leaves, of many tree species in Ontario. In southern Ontario, host species include sugar maple (Acer saccharum), American beech (Fagus grandifolia), eastern white pine (Pinus strobus), balsam fir (Abies balsamea), Colorado blue spruce (Picea pungens), but their preferred host are oak (Quercus sp.) species.

Outbreaks normally last 2-3 years and population collapse is caused by natural factors such as cool wet weather, cold winter temperatures (below -20 to -25 Celcius), starvation due to lack of food, biocontrols such as nuclear polyhedrosis virus (NPV) and Entomophaga maimaiga fungus, egg parasitoids, ground beetles, and larval parasitoids.

Photo: www.ontario.ca