Interception and Eradication of Lymantria Moths in British Columbia, Canada: 50-Year History of a Thwarted Invasion

The spongy moth ( Lymantria dispar dispar ) and several of its close relatives (subspecies L . d . asiatica and L . d . japonica , and the species L . umbrosa and L . albescens ) are defoliators that pose an invasion threat in Canada and around the world. Members of this group can disperse far beyond their native ranges on vehicles and freight, and they can attack a wide array of deciduous and coniferous plant species globally. Occasional population outbreaks can also defoliate large geographic areas over multiple years, resulting in widespread tree decline or mortality and a variety of other ecological impacts. As a result, these moths pose a serious threat to natural and urban forests. We summarize the history of Lymantria moth incursions into the province of British Columbia, Canada, since the start of regular surveillance and eradication began in that region near the end of the 1970s. Proactive public policy and a science-based management approach have contributed to a successful partnership between the federal and BC provincial governments to thwart a Lymantria moth invasion for nearly 50 years. Information © The Authors 2025