Biological Control of Dutch Elm Disease - Atlantic Forestry Centre

Biological Control of Dutch Elm Disease - Atlantic Forestry Centre: "The condition is caused by a fungus, Ophiostoma ulmi, whose spores are carried by small beetles that have bred beneath the bark of diseased elms, to healthy trees where the insects feed and over-winter. The fungus spreads via the water-conducting system of the tree and causes wilting and yellowing of the leaves and, ultimately, death of the tree."