From Backyard Escape to Century-Long Forest Pest
An 1869 backyard silkworm breeding experiment by Étienne Trouvelot led to a wind-dispersed escape of gypsy moth caterpillars. By 1889 a 360-square-mile outbreak near Medford, Massachusetts revealed how a slow-burn invasion can take decades to bloom, eventually spreading across North America to strip millions of acres in bad years and cost roughly $868 million annually in damages. The moth’s spread was aided by few natural predators and wind-assisted dispersal, with a fungal pathogen arriving in 1989 helping curb some outbreaks. Even after more than a century, containment remains a costly, ongoing effort, illustrating how a small careless moment can trigger a long tail of ecological impact.
