PPDL Picture of the Week for
November 26, 2012

As if Emerald Ash Borer wasn't enough...

Tom Creswell, PPDL Director, Purdue University

While homeowners across the Midwest and much of the northern Atlantic region watch our ash trees succumb to Emerald Ash Borer (EAB) our friends in Europe are facing an equally devastating but different threat to ash. In Europe, the ash trees are dying from a fungal disease rather than an insect attack. The pathogen is the fungus Chalara fraxinea, and the disease is known as Ash Dieback. It was first discovered in Poland in 1992 and has since steadily moved across Europe to 21 countries, including Great Britain. This fungal disease of ash has not yet been confirmed in the United States.

The fungus causes bleeding cankers and damage to young stems. When several cankers attack a young tree it is girdled and may die within one season. Older trees survive longer but suffer severe dieback and must be removed after several years of attack. The fungal spores are thought to spread mainly by wind transport but long distance spread by importing infected young ash trees from infested areas has been shown to speed the movement across borders. While we may not be dealing with the same problem as our European neighbors we can certainly sympathize and hopefully use this news as a reminder to be vigilant. There are many invasive insects and diseases capable of causing widespread damage to our forests, landscapes and crops if introduced into the US. Please support efforts to prevent the entry and spread of invasive species.

More information on Ash Dieback in Europe: http://www.bbc.co.uk/news/science-environment-20128172

Visit the USDA National Invasive Species Information Center (http://www.invasivespeciesinfo.gov/) for more information and to find out what you can do to help prevent the spread of invasive species.

Stop The Spread, Indiana Department of Natural Resources: http://www.in.gov/dnr/3123.htm

Beetle Busters, USDA: http://beetlebusters.info/

Click image to enlarge

Canker on ash

Photo by Great Britain Forestry Commission / Thomas Kirisits

Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service