Dating the Emerald Ash Borer

Emerald Ash Borer

Emerald Ash Borer (Agrilus planipennis, EAB), an invasive pest in North America was first detected in the Detroit, Michigan area in 2002 after numerous ash trees were observed to be dead or in decline. Emearld ash borer can live in an ash tree for several years before symptoms become severe. Entomologists have suspected that EAB was present well before 2002. A group of scientists* collected tree rings from ash trees in Michigan in order to determine when the EAB was first present and map its early spread. They were able to determine the year of death for each tree killed by EAB. They found the earliest killed trees near the community of Canton. They also noted that the population had spread far beyond the area of initial infestation by the time it was discovered. They suggest that EAB was present in the area at least by the early 1990s and maybe as early as the late 1980s.

For entomologists trying to slow the spread of this pest, it suggests that efforts to quarantine the pest should encompass a more extensive area to be certain it is contained within the quarantine zone. The lack of good attractants and early detection methods have limited the ability to intervene in a timely manner.

*Siegert, Nathan W.; McCullough, Deborah G.; Liebhold, Andrew M.; Telewski, Frank W. 2014. Dendrochronological reconstruction of the epicentre and early spread of emerald ash borer in North America. Diversity and Distributions
http://dx.doi.org/10.1111/ddi.12212