Dutch elm disease

A disease of elm trees caused by the fungus Ceratocystis ulmi, spread by the European elm bark beetle Scolytus multistriatus and by the contact of the roots of healthy elms with those of infected trees. It produces brown streaks in the wood and results in the eventual death of the tree. No cure has been discovered, but prevention methods include the injection of insecticide into healthy trees and the destruction of all elms in infected areas.