Dutch elm disease

Disease of elm trees Ulmus, principally Dutch, English, and American elm, caused by the fungus Certocystis ulmi. The fungus is usually spread from tree to tree by the elm-bark beetle, which lays its eggs beneath the bark. The disease has no cure, and control methods involve injecting insecticide into the trees annually to prevent infection, or the destruction of all elms in a broad band around an infected area, to keep the beetles out.

The disease was first described in the Netherlands and by the early 1930s had spread across Britain and continental Europe, as well as North America.

The disease killed 80 million elms in the USA 1930–96.