A natural biological control of Dutch elm disease

Abstract

Since its arrival in the late 1960s, the aggressive strain of Ceratocystis ulmi, the fungus that causes Dutch elm disease, has destroyed over 20 million elms in Britain and subsequently inflicted similar heavy losses across much of continental Europe^1,2. Successful control of the disease has been achieved only locally, using intensive sanitation and fungicide injection programmes^3,4. However, it has recently become apparent that disease spread may also be limited naturally. I present here evidence of a biological control of Dutch elm disease which could be exerting an important effect in some parts of Britain. This control process acts by preventing successful breeding of scolytid beetles which are the vectors of C. ulmi.